Ignore:
Timestamp:
14/06/14 11:20:37 (8 years ago)
Author:
julian.reschke@…
Message:

update to latest version of rfc2629.xslt, regen all HTML

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1 edited

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  • draft-ietf-httpbis/15/p2-semantics.html

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    397400      <link rel="Appendix" title="B Collected ABNF" href="#rfc.section.B">
    398401      <link rel="Appendix" title="C Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.C">
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    400403      <link rel="schema.dct" href="http://purl.org/dc/terms/">
    401404      <meta name="dct.creator" content="Fielding, R.">
     
    426429            </tr>
    427430            <tr>
    428                <td class="left">Obsoletes: <a href="http://tools.ietf.org/html/rfc2616">2616</a> (if approved)
     431               <td class="left">Obsoletes: <a href="https://tools.ietf.org/html/rfc2616">2616</a> (if approved)
    429432               </td>
    430433               <td class="right">J. Gettys</td>
    431434            </tr>
    432435            <tr>
    433                <td class="left">Updates: <a href="http://tools.ietf.org/html/rfc2817">2817</a> (if approved)
     436               <td class="left">Updates: <a href="https://tools.ietf.org/html/rfc2817">2817</a> (if approved)
    434437               </td>
    435438               <td class="right">Alcatel-Lucent</td>
     
    498501      </table>
    499502      <p class="title">HTTP/1.1, part 2: Message Semantics<br><span class="filename">draft-ietf-httpbis-p2-semantics-15</span></p>
    500       <h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1> 
     503      <h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1>
    501504      <p>The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information
    502505         systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 2 of the
     
    504507         2 defines the semantics of HTTP messages as expressed by request methods, request header fields, response status codes, and
    505508         response header fields.
    506       </p> 
    507       <h1 id="rfc.note.1"><a href="#rfc.note.1">Editorial Note (To be removed by RFC Editor)</a></h1> 
     509      </p>
     510      <h1 id="rfc.note.1"><a href="#rfc.note.1">Editorial Note (To be removed by RFC Editor)</a></h1>
    508511      <p>Discussion of this draft should take place on the HTTPBIS working group mailing list (ietf-http-wg@w3.org), which is archived
    509512         at &lt;<a href="http://lists.w3.org/Archives/Public/ietf-http-wg/">http://lists.w3.org/Archives/Public/ietf-http-wg/</a>&gt;.
    510       </p> 
     513      </p>
    511514      <p>The current issues list is at &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/report/3">http://tools.ietf.org/wg/httpbis/trac/report/3</a>&gt; and related documents (including fancy diffs) can be found at &lt;<a href="http://tools.ietf.org/wg/httpbis/">http://tools.ietf.org/wg/httpbis/</a>&gt;.
    512       </p> 
     515      </p>
    513516      <p>The changes in this draft are summarized in <a href="#changes.since.14" title="Since draft-ietf-httpbis-p2-semantics-14">Appendix&nbsp;C.16</a>.
    514       </p>
    515       <h1><a id="rfc.status" href="#rfc.status">Status of This Memo</a></h1>
    516       <p>This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.</p>
    517       <p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute
    518          working documents as Internet-Drafts. The list of current Internet-Drafts is at <a href="http://datatracker.ietf.org/drafts/current/">http://datatracker.ietf.org/drafts/current/</a>.
    519517      </p>
    520       <p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other
    521          documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work
    522          in progress”.
    523       </p>
    524       <p>This Internet-Draft will expire on January 12, 2012.</p>
    525       <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1>
    526       <p>Copyright © 2011 IETF Trust and the persons identified as the document authors. All rights reserved.</p>
    527       <p>This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights
    528          and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License
    529          text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified
    530          BSD License.
    531       </p>
    532       <p>This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November
    533          10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to
    534          allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s)
    535          controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative
    536          works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate
    537          it into languages other than English.
    538       </p>
     518      <div id="rfc.status">
     519         <h1><a href="#rfc.status">Status of This Memo</a></h1>
     520         <p>This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.</p>
     521         <p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute
     522            working documents as Internet-Drafts. The list of current Internet-Drafts is at <a href="http://datatracker.ietf.org/drafts/current/">http://datatracker.ietf.org/drafts/current/</a>.
     523         </p>
     524         <p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other
     525            documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work
     526            in progress”.
     527         </p>
     528         <p>This Internet-Draft will expire on January 12, 2012.</p>
     529      </div>
     530      <div id="rfc.copyrightnotice">
     531         <h1><a href="#rfc.copyrightnotice">Copyright Notice</a></h1>
     532         <p>Copyright © 2011 IETF Trust and the persons identified as the document authors. All rights reserved.</p>
     533         <p>This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights
     534            and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License
     535            text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified
     536            BSD License.
     537         </p>
     538         <p>This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November
     539            10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to
     540            allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s)
     541            controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative
     542            works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate
     543            it into languages other than English.
     544         </p>
     545      </div>
    539546      <hr class="noprint">
    540547      <h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1>
    541548      <ul class="toc">
    542          <li>1.&nbsp;&nbsp;&nbsp;<a href="#introduction">Introduction</a><ul>
    543                <li>1.1&nbsp;&nbsp;&nbsp;<a href="#intro.requirements">Requirements</a></li>
    544                <li>1.2&nbsp;&nbsp;&nbsp;<a href="#notation">Syntax Notation</a><ul>
    545                      <li>1.2.1&nbsp;&nbsp;&nbsp;<a href="#core.rules">Core Rules</a></li>
    546                      <li>1.2.2&nbsp;&nbsp;&nbsp;<a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></li>
     549         <li><a href="#rfc.section.1">1.</a>&nbsp;&nbsp;&nbsp;<a href="#introduction">Introduction</a><ul>
     550               <li><a href="#rfc.section.1.1">1.1</a>&nbsp;&nbsp;&nbsp;<a href="#intro.requirements">Requirements</a></li>
     551               <li><a href="#rfc.section.1.2">1.2</a>&nbsp;&nbsp;&nbsp;<a href="#notation">Syntax Notation</a><ul>
     552                     <li><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;&nbsp;&nbsp;<a href="#core.rules">Core Rules</a></li>
     553                     <li><a href="#rfc.section.1.2.2">1.2.2</a>&nbsp;&nbsp;&nbsp;<a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></li>
    547554                  </ul>
    548555               </li>
    549556            </ul>
    550557         </li>
    551          <li>2.&nbsp;&nbsp;&nbsp;<a href="#method">Method</a><ul>
    552                <li>2.1&nbsp;&nbsp;&nbsp;<a href="#overview.of.methods">Overview of Methods</a></li>
    553                <li>2.2&nbsp;&nbsp;&nbsp;<a href="#method.registry">Method Registry</a><ul>
    554                      <li>2.2.1&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.methods">Considerations for New Methods</a></li>
     558         <li><a href="#rfc.section.2">2.</a>&nbsp;&nbsp;&nbsp;<a href="#method">Method</a><ul>
     559               <li><a href="#rfc.section.2.1">2.1</a>&nbsp;&nbsp;&nbsp;<a href="#overview.of.methods">Overview of Methods</a></li>
     560               <li><a href="#rfc.section.2.2">2.2</a>&nbsp;&nbsp;&nbsp;<a href="#method.registry">Method Registry</a><ul>
     561                     <li><a href="#rfc.section.2.2.1">2.2.1</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.methods">Considerations for New Methods</a></li>
    555562                  </ul>
    556563               </li>
    557564            </ul>
    558565         </li>
    559          <li>3.&nbsp;&nbsp;&nbsp;<a href="#request.header.fields">Request Header Fields</a></li>
    560          <li>4.&nbsp;&nbsp;&nbsp;<a href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a><ul>
    561                <li>4.1&nbsp;&nbsp;&nbsp;<a href="#overview.of.status.codes">Overview of Status Codes</a></li>
    562                <li>4.2&nbsp;&nbsp;&nbsp;<a href="#status.code.registry">Status Code Registry</a><ul>
    563                      <li>4.2.1&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></li>
     566         <li><a href="#rfc.section.3">3.</a>&nbsp;&nbsp;&nbsp;<a href="#request.header.fields">Request Header Fields</a></li>
     567         <li><a href="#rfc.section.4">4.</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a><ul>
     568               <li><a href="#rfc.section.4.1">4.1</a>&nbsp;&nbsp;&nbsp;<a href="#overview.of.status.codes">Overview of Status Codes</a></li>
     569               <li><a href="#rfc.section.4.2">4.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.registry">Status Code Registry</a><ul>
     570                     <li><a href="#rfc.section.4.2.1">4.2.1</a>&nbsp;&nbsp;&nbsp;<a href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></li>
    564571                  </ul>
    565572               </li>
    566573            </ul>
    567574         </li>
    568          <li>5.&nbsp;&nbsp;&nbsp;<a href="#response.header.fields">Response Header Fields</a></li>
    569          <li>6.&nbsp;&nbsp;&nbsp;<a href="#representation">Representation</a><ul>
    570                <li>6.1&nbsp;&nbsp;&nbsp;<a href="#identifying.response.associated.with.representation">Identifying the Resource Associated with a Representation</a></li>
     575         <li><a href="#rfc.section.5">5.</a>&nbsp;&nbsp;&nbsp;<a href="#response.header.fields">Response Header Fields</a></li>
     576         <li><a href="#rfc.section.6">6.</a>&nbsp;&nbsp;&nbsp;<a href="#representation">Representation</a><ul>
     577               <li><a href="#rfc.section.6.1">6.1</a>&nbsp;&nbsp;&nbsp;<a href="#identifying.response.associated.with.representation">Identifying the Resource Associated with a Representation</a></li>
    571578            </ul>
    572579         </li>
    573          <li>7.&nbsp;&nbsp;&nbsp;<a href="#method.definitions">Method Definitions</a><ul>
    574                <li>7.1&nbsp;&nbsp;&nbsp;<a href="#safe.and.idempotent">Safe and Idempotent Methods</a><ul>
    575                      <li>7.1.1&nbsp;&nbsp;&nbsp;<a href="#safe.methods">Safe Methods</a></li>
    576                      <li>7.1.2&nbsp;&nbsp;&nbsp;<a href="#idempotent.methods">Idempotent Methods</a></li>
     580         <li><a href="#rfc.section.7">7.</a>&nbsp;&nbsp;&nbsp;<a href="#method.definitions">Method Definitions</a><ul>
     581               <li><a href="#rfc.section.7.1">7.1</a>&nbsp;&nbsp;&nbsp;<a href="#safe.and.idempotent">Safe and Idempotent Methods</a><ul>
     582                     <li><a href="#rfc.section.7.1.1">7.1.1</a>&nbsp;&nbsp;&nbsp;<a href="#safe.methods">Safe Methods</a></li>
     583                     <li><a href="#rfc.section.7.1.2">7.1.2</a>&nbsp;&nbsp;&nbsp;<a href="#idempotent.methods">Idempotent Methods</a></li>
    577584                  </ul>
    578585               </li>
    579                <li>7.2&nbsp;&nbsp;&nbsp;<a href="#OPTIONS">OPTIONS</a></li>
    580                <li>7.3&nbsp;&nbsp;&nbsp;<a href="#GET">GET</a></li>
    581                <li>7.4&nbsp;&nbsp;&nbsp;<a href="#HEAD">HEAD</a></li>
    582                <li>7.5&nbsp;&nbsp;&nbsp;<a href="#POST">POST</a></li>
    583                <li>7.6&nbsp;&nbsp;&nbsp;<a href="#PUT">PUT</a></li>
    584                <li>7.7&nbsp;&nbsp;&nbsp;<a href="#DELETE">DELETE</a></li>
    585                <li>7.8&nbsp;&nbsp;&nbsp;<a href="#TRACE">TRACE</a></li>
    586                <li>7.9&nbsp;&nbsp;&nbsp;<a href="#CONNECT">CONNECT</a><ul>
    587                      <li>7.9.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.7.9.1">Establishing a Tunnel with CONNECT</a></li>
     586               <li><a href="#rfc.section.7.2">7.2</a>&nbsp;&nbsp;&nbsp;<a href="#OPTIONS">OPTIONS</a></li>
     587               <li><a href="#rfc.section.7.3">7.3</a>&nbsp;&nbsp;&nbsp;<a href="#GET">GET</a></li>
     588               <li><a href="#rfc.section.7.4">7.4</a>&nbsp;&nbsp;&nbsp;<a href="#HEAD">HEAD</a></li>
     589               <li><a href="#rfc.section.7.5">7.5</a>&nbsp;&nbsp;&nbsp;<a href="#POST">POST</a></li>
     590               <li><a href="#rfc.section.7.6">7.6</a>&nbsp;&nbsp;&nbsp;<a href="#PUT">PUT</a></li>
     591               <li><a href="#rfc.section.7.7">7.7</a>&nbsp;&nbsp;&nbsp;<a href="#DELETE">DELETE</a></li>
     592               <li><a href="#rfc.section.7.8">7.8</a>&nbsp;&nbsp;&nbsp;<a href="#TRACE">TRACE</a></li>
     593               <li><a href="#rfc.section.7.9">7.9</a>&nbsp;&nbsp;&nbsp;<a href="#CONNECT">CONNECT</a><ul>
     594                     <li><a href="#rfc.section.7.9.1">7.9.1</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.7.9.1">Establishing a Tunnel with CONNECT</a></li>
    588595                  </ul>
    589596               </li>
    590597            </ul>
    591598         </li>
    592          <li>8.&nbsp;&nbsp;&nbsp;<a href="#status.codes">Status Code Definitions</a><ul>
    593                <li>8.1&nbsp;&nbsp;&nbsp;<a href="#status.1xx">Informational 1xx</a><ul>
    594                      <li>8.1.1&nbsp;&nbsp;&nbsp;<a href="#status.100">100 Continue</a></li>
    595                      <li>8.1.2&nbsp;&nbsp;&nbsp;<a href="#status.101">101 Switching Protocols</a></li>
     599         <li><a href="#rfc.section.8">8.</a>&nbsp;&nbsp;&nbsp;<a href="#status.codes">Status Code Definitions</a><ul>
     600               <li><a href="#rfc.section.8.1">8.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.1xx">Informational 1xx</a><ul>
     601                     <li><a href="#rfc.section.8.1.1">8.1.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.100">100 Continue</a></li>
     602                     <li><a href="#rfc.section.8.1.2">8.1.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.101">101 Switching Protocols</a></li>
    596603                  </ul>
    597604               </li>
    598                <li>8.2&nbsp;&nbsp;&nbsp;<a href="#status.2xx">Successful 2xx</a><ul>
    599                      <li>8.2.1&nbsp;&nbsp;&nbsp;<a href="#status.200">200 OK</a></li>
    600                      <li>8.2.2&nbsp;&nbsp;&nbsp;<a href="#status.201">201 Created</a></li>
    601                      <li>8.2.3&nbsp;&nbsp;&nbsp;<a href="#status.202">202 Accepted</a></li>
    602                      <li>8.2.4&nbsp;&nbsp;&nbsp;<a href="#status.203">203 Non-Authoritative Information</a></li>
    603                      <li>8.2.5&nbsp;&nbsp;&nbsp;<a href="#status.204">204 No Content</a></li>
    604                      <li>8.2.6&nbsp;&nbsp;&nbsp;<a href="#status.205">205 Reset Content</a></li>
    605                      <li>8.2.7&nbsp;&nbsp;&nbsp;<a href="#status.206">206 Partial Content</a></li>
     605               <li><a href="#rfc.section.8.2">8.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.2xx">Successful 2xx</a><ul>
     606                     <li><a href="#rfc.section.8.2.1">8.2.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.200">200 OK</a></li>
     607                     <li><a href="#rfc.section.8.2.2">8.2.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.201">201 Created</a></li>
     608                     <li><a href="#rfc.section.8.2.3">8.2.3</a>&nbsp;&nbsp;&nbsp;<a href="#status.202">202 Accepted</a></li>
     609                     <li><a href="#rfc.section.8.2.4">8.2.4</a>&nbsp;&nbsp;&nbsp;<a href="#status.203">203 Non-Authoritative Information</a></li>
     610                     <li><a href="#rfc.section.8.2.5">8.2.5</a>&nbsp;&nbsp;&nbsp;<a href="#status.204">204 No Content</a></li>
     611                     <li><a href="#rfc.section.8.2.6">8.2.6</a>&nbsp;&nbsp;&nbsp;<a href="#status.205">205 Reset Content</a></li>
     612                     <li><a href="#rfc.section.8.2.7">8.2.7</a>&nbsp;&nbsp;&nbsp;<a href="#status.206">206 Partial Content</a></li>
    606613                  </ul>
    607614               </li>
    608                <li>8.3&nbsp;&nbsp;&nbsp;<a href="#status.3xx">Redirection 3xx</a><ul>
    609                      <li>8.3.1&nbsp;&nbsp;&nbsp;<a href="#status.300">300 Multiple Choices</a></li>
    610                      <li>8.3.2&nbsp;&nbsp;&nbsp;<a href="#status.301">301 Moved Permanently</a></li>
    611                      <li>8.3.3&nbsp;&nbsp;&nbsp;<a href="#status.302">302 Found</a></li>
    612                      <li>8.3.4&nbsp;&nbsp;&nbsp;<a href="#status.303">303 See Other</a></li>
    613                      <li>8.3.5&nbsp;&nbsp;&nbsp;<a href="#status.304">304 Not Modified</a></li>
    614                      <li>8.3.6&nbsp;&nbsp;&nbsp;<a href="#status.305">305 Use Proxy</a></li>
    615                      <li>8.3.7&nbsp;&nbsp;&nbsp;<a href="#status.306">306 (Unused)</a></li>
    616                      <li>8.3.8&nbsp;&nbsp;&nbsp;<a href="#status.307">307 Temporary Redirect</a></li>
     615               <li><a href="#rfc.section.8.3">8.3</a>&nbsp;&nbsp;&nbsp;<a href="#status.3xx">Redirection 3xx</a><ul>
     616                     <li><a href="#rfc.section.8.3.1">8.3.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.300">300 Multiple Choices</a></li>
     617                     <li><a href="#rfc.section.8.3.2">8.3.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.301">301 Moved Permanently</a></li>
     618                     <li><a href="#rfc.section.8.3.3">8.3.3</a>&nbsp;&nbsp;&nbsp;<a href="#status.302">302 Found</a></li>
     619                     <li><a href="#rfc.section.8.3.4">8.3.4</a>&nbsp;&nbsp;&nbsp;<a href="#status.303">303 See Other</a></li>
     620                     <li><a href="#rfc.section.8.3.5">8.3.5</a>&nbsp;&nbsp;&nbsp;<a href="#status.304">304 Not Modified</a></li>
     621                     <li><a href="#rfc.section.8.3.6">8.3.6</a>&nbsp;&nbsp;&nbsp;<a href="#status.305">305 Use Proxy</a></li>
     622                     <li><a href="#rfc.section.8.3.7">8.3.7</a>&nbsp;&nbsp;&nbsp;<a href="#status.306">306 (Unused)</a></li>
     623                     <li><a href="#rfc.section.8.3.8">8.3.8</a>&nbsp;&nbsp;&nbsp;<a href="#status.307">307 Temporary Redirect</a></li>
    617624                  </ul>
    618625               </li>
    619                <li>8.4&nbsp;&nbsp;&nbsp;<a href="#status.4xx">Client Error 4xx</a><ul>
    620                      <li>8.4.1&nbsp;&nbsp;&nbsp;<a href="#status.400">400 Bad Request</a></li>
    621                      <li>8.4.2&nbsp;&nbsp;&nbsp;<a href="#status.401">401 Unauthorized</a></li>
    622                      <li>8.4.3&nbsp;&nbsp;&nbsp;<a href="#status.402">402 Payment Required</a></li>
    623                      <li>8.4.4&nbsp;&nbsp;&nbsp;<a href="#status.403">403 Forbidden</a></li>
    624                      <li>8.4.5&nbsp;&nbsp;&nbsp;<a href="#status.404">404 Not Found</a></li>
    625                      <li>8.4.6&nbsp;&nbsp;&nbsp;<a href="#status.405">405 Method Not Allowed</a></li>
    626                      <li>8.4.7&nbsp;&nbsp;&nbsp;<a href="#status.406">406 Not Acceptable</a></li>
    627                      <li>8.4.8&nbsp;&nbsp;&nbsp;<a href="#status.407">407 Proxy Authentication Required</a></li>
    628                      <li>8.4.9&nbsp;&nbsp;&nbsp;<a href="#status.408">408 Request Timeout</a></li>
    629                      <li>8.4.10&nbsp;&nbsp;&nbsp;<a href="#status.409">409 Conflict</a></li>
    630                      <li>8.4.11&nbsp;&nbsp;&nbsp;<a href="#status.410">410 Gone</a></li>
    631                      <li>8.4.12&nbsp;&nbsp;&nbsp;<a href="#status.411">411 Length Required</a></li>
    632                      <li>8.4.13&nbsp;&nbsp;&nbsp;<a href="#status.412">412 Precondition Failed</a></li>
    633                      <li>8.4.14&nbsp;&nbsp;&nbsp;<a href="#status.413">413 Request Representation Too Large</a></li>
    634                      <li>8.4.15&nbsp;&nbsp;&nbsp;<a href="#status.414">414 URI Too Long</a></li>
    635                      <li>8.4.16&nbsp;&nbsp;&nbsp;<a href="#status.415">415 Unsupported Media Type</a></li>
    636                      <li>8.4.17&nbsp;&nbsp;&nbsp;<a href="#status.416">416 Requested Range Not Satisfiable</a></li>
    637                      <li>8.4.18&nbsp;&nbsp;&nbsp;<a href="#status.417">417 Expectation Failed</a></li>
    638                      <li>8.4.19&nbsp;&nbsp;&nbsp;<a href="#status.426">426 Upgrade Required</a></li>
     626               <li><a href="#rfc.section.8.4">8.4</a>&nbsp;&nbsp;&nbsp;<a href="#status.4xx">Client Error 4xx</a><ul>
     627                     <li><a href="#rfc.section.8.4.1">8.4.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.400">400 Bad Request</a></li>
     628                     <li><a href="#rfc.section.8.4.2">8.4.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.401">401 Unauthorized</a></li>
     629                     <li><a href="#rfc.section.8.4.3">8.4.3</a>&nbsp;&nbsp;&nbsp;<a href="#status.402">402 Payment Required</a></li>
     630                     <li><a href="#rfc.section.8.4.4">8.4.4</a>&nbsp;&nbsp;&nbsp;<a href="#status.403">403 Forbidden</a></li>
     631                     <li><a href="#rfc.section.8.4.5">8.4.5</a>&nbsp;&nbsp;&nbsp;<a href="#status.404">404 Not Found</a></li>
     632                     <li><a href="#rfc.section.8.4.6">8.4.6</a>&nbsp;&nbsp;&nbsp;<a href="#status.405">405 Method Not Allowed</a></li>
     633                     <li><a href="#rfc.section.8.4.7">8.4.7</a>&nbsp;&nbsp;&nbsp;<a href="#status.406">406 Not Acceptable</a></li>
     634                     <li><a href="#rfc.section.8.4.8">8.4.8</a>&nbsp;&nbsp;&nbsp;<a href="#status.407">407 Proxy Authentication Required</a></li>
     635                     <li><a href="#rfc.section.8.4.9">8.4.9</a>&nbsp;&nbsp;&nbsp;<a href="#status.408">408 Request Timeout</a></li>
     636                     <li><a href="#rfc.section.8.4.10">8.4.10</a>&nbsp;&nbsp;&nbsp;<a href="#status.409">409 Conflict</a></li>
     637                     <li><a href="#rfc.section.8.4.11">8.4.11</a>&nbsp;&nbsp;&nbsp;<a href="#status.410">410 Gone</a></li>
     638                     <li><a href="#rfc.section.8.4.12">8.4.12</a>&nbsp;&nbsp;&nbsp;<a href="#status.411">411 Length Required</a></li>
     639                     <li><a href="#rfc.section.8.4.13">8.4.13</a>&nbsp;&nbsp;&nbsp;<a href="#status.412">412 Precondition Failed</a></li>
     640                     <li><a href="#rfc.section.8.4.14">8.4.14</a>&nbsp;&nbsp;&nbsp;<a href="#status.413">413 Request Representation Too Large</a></li>
     641                     <li><a href="#rfc.section.8.4.15">8.4.15</a>&nbsp;&nbsp;&nbsp;<a href="#status.414">414 URI Too Long</a></li>
     642                     <li><a href="#rfc.section.8.4.16">8.4.16</a>&nbsp;&nbsp;&nbsp;<a href="#status.415">415 Unsupported Media Type</a></li>
     643                     <li><a href="#rfc.section.8.4.17">8.4.17</a>&nbsp;&nbsp;&nbsp;<a href="#status.416">416 Requested Range Not Satisfiable</a></li>
     644                     <li><a href="#rfc.section.8.4.18">8.4.18</a>&nbsp;&nbsp;&nbsp;<a href="#status.417">417 Expectation Failed</a></li>
     645                     <li><a href="#rfc.section.8.4.19">8.4.19</a>&nbsp;&nbsp;&nbsp;<a href="#status.426">426 Upgrade Required</a></li>
    639646                  </ul>
    640647               </li>
    641                <li>8.5&nbsp;&nbsp;&nbsp;<a href="#status.5xx">Server Error 5xx</a><ul>
    642                      <li>8.5.1&nbsp;&nbsp;&nbsp;<a href="#status.500">500 Internal Server Error</a></li>
    643                      <li>8.5.2&nbsp;&nbsp;&nbsp;<a href="#status.501">501 Not Implemented</a></li>
    644                      <li>8.5.3&nbsp;&nbsp;&nbsp;<a href="#status.502">502 Bad Gateway</a></li>
    645                      <li>8.5.4&nbsp;&nbsp;&nbsp;<a href="#status.503">503 Service Unavailable</a></li>
    646                      <li>8.5.5&nbsp;&nbsp;&nbsp;<a href="#status.504">504 Gateway Timeout</a></li>
    647                      <li>8.5.6&nbsp;&nbsp;&nbsp;<a href="#status.505">505 HTTP Version Not Supported</a></li>
     648               <li><a href="#rfc.section.8.5">8.5</a>&nbsp;&nbsp;&nbsp;<a href="#status.5xx">Server Error 5xx</a><ul>
     649                     <li><a href="#rfc.section.8.5.1">8.5.1</a>&nbsp;&nbsp;&nbsp;<a href="#status.500">500 Internal Server Error</a></li>
     650                     <li><a href="#rfc.section.8.5.2">8.5.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.501">501 Not Implemented</a></li>
     651                     <li><a href="#rfc.section.8.5.3">8.5.3</a>&nbsp;&nbsp;&nbsp;<a href="#status.502">502 Bad Gateway</a></li>
     652                     <li><a href="#rfc.section.8.5.4">8.5.4</a>&nbsp;&nbsp;&nbsp;<a href="#status.503">503 Service Unavailable</a></li>
     653                     <li><a href="#rfc.section.8.5.5">8.5.5</a>&nbsp;&nbsp;&nbsp;<a href="#status.504">504 Gateway Timeout</a></li>
     654                     <li><a href="#rfc.section.8.5.6">8.5.6</a>&nbsp;&nbsp;&nbsp;<a href="#status.505">505 HTTP Version Not Supported</a></li>
    648655                  </ul>
    649656               </li>
    650657            </ul>
    651658         </li>
    652          <li>9.&nbsp;&nbsp;&nbsp;<a href="#header.fields">Header Field Definitions</a><ul>
    653                <li>9.1&nbsp;&nbsp;&nbsp;<a href="#header.allow">Allow</a></li>
    654                <li>9.2&nbsp;&nbsp;&nbsp;<a href="#header.expect">Expect</a></li>
    655                <li>9.3&nbsp;&nbsp;&nbsp;<a href="#header.from">From</a></li>
    656                <li>9.4&nbsp;&nbsp;&nbsp;<a href="#header.location">Location</a></li>
    657                <li>9.5&nbsp;&nbsp;&nbsp;<a href="#header.max-forwards">Max-Forwards</a></li>
    658                <li>9.6&nbsp;&nbsp;&nbsp;<a href="#header.referer">Referer</a></li>
    659                <li>9.7&nbsp;&nbsp;&nbsp;<a href="#header.retry-after">Retry-After</a></li>
    660                <li>9.8&nbsp;&nbsp;&nbsp;<a href="#header.server">Server</a></li>
    661                <li>9.9&nbsp;&nbsp;&nbsp;<a href="#header.user-agent">User-Agent</a></li>
     659         <li><a href="#rfc.section.9">9.</a>&nbsp;&nbsp;&nbsp;<a href="#header.fields">Header Field Definitions</a><ul>
     660               <li><a href="#rfc.section.9.1">9.1</a>&nbsp;&nbsp;&nbsp;<a href="#header.allow">Allow</a></li>
     661               <li><a href="#rfc.section.9.2">9.2</a>&nbsp;&nbsp;&nbsp;<a href="#header.expect">Expect</a></li>
     662               <li><a href="#rfc.section.9.3">9.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.from">From</a></li>
     663               <li><a href="#rfc.section.9.4">9.4</a>&nbsp;&nbsp;&nbsp;<a href="#header.location">Location</a></li>
     664               <li><a href="#rfc.section.9.5">9.5</a>&nbsp;&nbsp;&nbsp;<a href="#header.max-forwards">Max-Forwards</a></li>
     665               <li><a href="#rfc.section.9.6">9.6</a>&nbsp;&nbsp;&nbsp;<a href="#header.referer">Referer</a></li>
     666               <li><a href="#rfc.section.9.7">9.7</a>&nbsp;&nbsp;&nbsp;<a href="#header.retry-after">Retry-After</a></li>
     667               <li><a href="#rfc.section.9.8">9.8</a>&nbsp;&nbsp;&nbsp;<a href="#header.server">Server</a></li>
     668               <li><a href="#rfc.section.9.9">9.9</a>&nbsp;&nbsp;&nbsp;<a href="#header.user-agent">User-Agent</a></li>
    662669            </ul>
    663670         </li>
    664          <li>10.&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
    665                <li>10.1&nbsp;&nbsp;&nbsp;<a href="#method.registration">Method Registry</a></li>
    666                <li>10.2&nbsp;&nbsp;&nbsp;<a href="#status.code.registration">Status Code Registry</a></li>
    667                <li>10.3&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Header Field Registration</a></li>
     671         <li><a href="#rfc.section.10">10.</a>&nbsp;&nbsp;&nbsp;<a href="#IANA.considerations">IANA Considerations</a><ul>
     672               <li><a href="#rfc.section.10.1">10.1</a>&nbsp;&nbsp;&nbsp;<a href="#method.registration">Method Registry</a></li>
     673               <li><a href="#rfc.section.10.2">10.2</a>&nbsp;&nbsp;&nbsp;<a href="#status.code.registration">Status Code Registry</a></li>
     674               <li><a href="#rfc.section.10.3">10.3</a>&nbsp;&nbsp;&nbsp;<a href="#header.field.registration">Header Field Registration</a></li>
    668675            </ul>
    669676         </li>
    670          <li>11.&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul>
    671                <li>11.1&nbsp;&nbsp;&nbsp;<a href="#security.sensitive">Transfer of Sensitive Information</a></li>
    672                <li>11.2&nbsp;&nbsp;&nbsp;<a href="#encoding.sensitive.information.in.uris">Encoding Sensitive Information in URIs</a></li>
    673                <li>11.3&nbsp;&nbsp;&nbsp;<a href="#location.spoofing">Location Headers and Spoofing</a></li>
    674                <li>11.4&nbsp;&nbsp;&nbsp;<a href="#rfc.section.11.4">Security Considerations for CONNECT</a></li>
     677         <li><a href="#rfc.section.11">11.</a>&nbsp;&nbsp;&nbsp;<a href="#security.considerations">Security Considerations</a><ul>
     678               <li><a href="#rfc.section.11.1">11.1</a>&nbsp;&nbsp;&nbsp;<a href="#security.sensitive">Transfer of Sensitive Information</a></li>
     679               <li><a href="#rfc.section.11.2">11.2</a>&nbsp;&nbsp;&nbsp;<a href="#encoding.sensitive.information.in.uris">Encoding Sensitive Information in URIs</a></li>
     680               <li><a href="#rfc.section.11.3">11.3</a>&nbsp;&nbsp;&nbsp;<a href="#location.spoofing">Location Headers and Spoofing</a></li>
     681               <li><a href="#rfc.section.11.4">11.4</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.11.4">Security Considerations for CONNECT</a></li>
    675682            </ul>
    676683         </li>
    677          <li>12.&nbsp;&nbsp;&nbsp;<a href="#ack">Acknowledgments</a></li>
    678          <li>13.&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
    679                <li>13.1&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
    680                <li>13.2&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
     684         <li><a href="#rfc.section.12">12.</a>&nbsp;&nbsp;&nbsp;<a href="#ack">Acknowledgments</a></li>
     685         <li><a href="#rfc.section.13">13.</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references">References</a><ul>
     686               <li><a href="#rfc.section.13.1">13.1</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.1">Normative References</a></li>
     687               <li><a href="#rfc.section.13.2">13.2</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.references.2">Informative References</a></li>
    681688            </ul>
    682689         </li>
    683          <li><a href="#rfc.authors">Authors' Addresses</a></li>
    684          <li>A.&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616">Changes from RFC 2616</a></li>
    685          <li>B.&nbsp;&nbsp;&nbsp;<a href="#collected.abnf">Collected ABNF</a></li>
    686          <li>C.&nbsp;&nbsp;&nbsp;<a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul>
    687                <li>C.1&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.1">Since RFC 2616</a></li>
    688                <li>C.2&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.2">Since draft-ietf-httpbis-p2-semantics-00</a></li>
    689                <li>C.3&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.3">Since draft-ietf-httpbis-p2-semantics-01</a></li>
    690                <li>C.4&nbsp;&nbsp;&nbsp;<a href="#changes.since.02">Since draft-ietf-httpbis-p2-semantics-02</a></li>
    691                <li>C.5&nbsp;&nbsp;&nbsp;<a href="#changes.since.03">Since draft-ietf-httpbis-p2-semantics-03</a></li>
    692                <li>C.6&nbsp;&nbsp;&nbsp;<a href="#changes.since.04">Since draft-ietf-httpbis-p2-semantics-04</a></li>
    693                <li>C.7&nbsp;&nbsp;&nbsp;<a href="#changes.since.05">Since draft-ietf-httpbis-p2-semantics-05</a></li>
    694                <li>C.8&nbsp;&nbsp;&nbsp;<a href="#changes.since.06">Since draft-ietf-httpbis-p2-semantics-06</a></li>
    695                <li>C.9&nbsp;&nbsp;&nbsp;<a href="#changes.since.07">Since draft-ietf-httpbis-p2-semantics-07</a></li>
    696                <li>C.10&nbsp;&nbsp;&nbsp;<a href="#changes.since.08">Since draft-ietf-httpbis-p2-semantics-08</a></li>
    697                <li>C.11&nbsp;&nbsp;&nbsp;<a href="#changes.since.09">Since draft-ietf-httpbis-p2-semantics-09</a></li>
    698                <li>C.12&nbsp;&nbsp;&nbsp;<a href="#changes.since.10">Since draft-ietf-httpbis-p2-semantics-10</a></li>
    699                <li>C.13&nbsp;&nbsp;&nbsp;<a href="#changes.since.11">Since draft-ietf-httpbis-p2-semantics-11</a></li>
    700                <li>C.14&nbsp;&nbsp;&nbsp;<a href="#changes.since.12">Since draft-ietf-httpbis-p2-semantics-12</a></li>
    701                <li>C.15&nbsp;&nbsp;&nbsp;<a href="#changes.since.13">Since draft-ietf-httpbis-p2-semantics-13</a></li>
    702                <li>C.16&nbsp;&nbsp;&nbsp;<a href="#changes.since.14">Since draft-ietf-httpbis-p2-semantics-14</a></li>
     690         <li><a href="#rfc.section.A">A.</a>&nbsp;&nbsp;&nbsp;<a href="#changes.from.rfc.2616">Changes from RFC 2616</a></li>
     691         <li><a href="#rfc.section.B">B.</a>&nbsp;&nbsp;&nbsp;<a href="#collected.abnf">Collected ABNF</a></li>
     692         <li><a href="#rfc.section.C">C.</a>&nbsp;&nbsp;&nbsp;<a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul>
     693               <li><a href="#rfc.section.C.1">C.1</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.1">Since RFC 2616</a></li>
     694               <li><a href="#rfc.section.C.2">C.2</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.2">Since draft-ietf-httpbis-p2-semantics-00</a></li>
     695               <li><a href="#rfc.section.C.3">C.3</a>&nbsp;&nbsp;&nbsp;<a href="#rfc.section.C.3">Since draft-ietf-httpbis-p2-semantics-01</a></li>
     696               <li><a href="#rfc.section.C.4">C.4</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.02">Since draft-ietf-httpbis-p2-semantics-02</a></li>
     697               <li><a href="#rfc.section.C.5">C.5</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.03">Since draft-ietf-httpbis-p2-semantics-03</a></li>
     698               <li><a href="#rfc.section.C.6">C.6</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.04">Since draft-ietf-httpbis-p2-semantics-04</a></li>
     699               <li><a href="#rfc.section.C.7">C.7</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.05">Since draft-ietf-httpbis-p2-semantics-05</a></li>
     700               <li><a href="#rfc.section.C.8">C.8</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.06">Since draft-ietf-httpbis-p2-semantics-06</a></li>
     701               <li><a href="#rfc.section.C.9">C.9</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.07">Since draft-ietf-httpbis-p2-semantics-07</a></li>
     702               <li><a href="#rfc.section.C.10">C.10</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.08">Since draft-ietf-httpbis-p2-semantics-08</a></li>
     703               <li><a href="#rfc.section.C.11">C.11</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.09">Since draft-ietf-httpbis-p2-semantics-09</a></li>
     704               <li><a href="#rfc.section.C.12">C.12</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.10">Since draft-ietf-httpbis-p2-semantics-10</a></li>
     705               <li><a href="#rfc.section.C.13">C.13</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.11">Since draft-ietf-httpbis-p2-semantics-11</a></li>
     706               <li><a href="#rfc.section.C.14">C.14</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.12">Since draft-ietf-httpbis-p2-semantics-12</a></li>
     707               <li><a href="#rfc.section.C.15">C.15</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.13">Since draft-ietf-httpbis-p2-semantics-13</a></li>
     708               <li><a href="#rfc.section.C.16">C.16</a>&nbsp;&nbsp;&nbsp;<a href="#changes.since.14">Since draft-ietf-httpbis-p2-semantics-14</a></li>
    703709            </ul>
    704710         </li>
    705711         <li><a href="#rfc.index">Index</a></li>
     712         <li><a href="#rfc.authors">Authors' Addresses</a></li>
    706713      </ul>
    707       <h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a>&nbsp;<a id="introduction" href="#introduction">Introduction</a></h1>
    708       <p id="rfc.section.1.p.1">This document defines HTTP/1.1 request and response semantics. Each HTTP message, as defined in <a href="#Part1" id="rfc.xref.Part1.1"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, is in the form of either a request or a response. An HTTP server listens on a connection for HTTP requests and responds
    709          to each request, in the order received on that connection, with one or more HTTP response messages. This document defines
    710          the commonly agreed upon semantics of the HTTP uniform interface, the intentions defined by each request method, and the various
    711          response messages that might be expected as a result of applying that method to the target resource.
    712       </p>
    713       <p id="rfc.section.1.p.2">This document is currently disorganized in order to minimize the changes between drafts and enable reviewers to see the smaller
    714          errata changes. A future draft will reorganize the sections to better reflect the content. In particular, the sections will
    715          be ordered according to the typical processing of an HTTP request message (after message parsing): resource mapping, methods,
    716          request modifying header fields, response status, status modifying header fields, and resource metadata. The current mess
    717          reflects how widely dispersed these topics and associated requirements had become in <a href="#RFC2616" id="rfc.xref.RFC2616.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
    718       </p>
    719       <h2 id="rfc.section.1.1"><a href="#rfc.section.1.1">1.1</a>&nbsp;<a id="intro.requirements" href="#intro.requirements">Requirements</a></h2>
    720       <p id="rfc.section.1.1.p.1">The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
    721          in this document are to be interpreted as described in <a href="#RFC2119" id="rfc.xref.RFC2119.1"><cite title="Key words for use in RFCs to Indicate Requirement Levels">[RFC2119]</cite></a>.
    722       </p>
    723       <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the "MUST" or "REQUIRED" level requirements for the
    724          protocols it implements. An implementation that satisfies all the "MUST" or "REQUIRED" level and all the "SHOULD" level requirements
    725          for its protocols is said to be "unconditionally compliant"; one that satisfies all the "MUST" level requirements but not
    726          all the "SHOULD" level requirements for its protocols is said to be "conditionally compliant".
    727       </p>
    728       <h2 id="rfc.section.1.2"><a href="#rfc.section.1.2">1.2</a>&nbsp;<a id="notation" href="#notation">Syntax Notation</a></h2>
    729       <p id="rfc.section.1.2.p.1">This specification uses the ABNF syntax defined in <a href="p1-messaging.html#notation" title="Syntax Notation">Section 1.2</a> of <a href="#Part1" id="rfc.xref.Part1.2"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> (which extends the syntax defined in <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> with a list rule). <a href="#collected.abnf" title="Collected ABNF">Appendix&nbsp;B</a> shows the collected ABNF, with the list rule expanded.
    730       </p>
    731       <p id="rfc.section.1.2.p.2">The following core rules are included by reference, as defined in <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, <a href="http://tools.ietf.org/html/rfc5234#appendix-B.1">Appendix B.1</a>: ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote), HEXDIG
    732          (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit sequence of data), SP (space), VCHAR (any visible USASCII character),
    733          and WSP (whitespace).
    734       </p>
    735       <h3 id="rfc.section.1.2.1"><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;<a id="core.rules" href="#core.rules">Core Rules</a></h3>
    736       <p id="rfc.section.1.2.1.p.1">The core rules below are defined in <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.3"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>:
    737       </p>
    738       <div id="rfc.figure.u.1"></div><pre class="inline">  <a href="#core.rules" class="smpl">quoted-string</a> = &lt;quoted-string, defined in <a href="#Part1" id="rfc.xref.Part1.4"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
     714      <div id="introduction">
     715         <h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a>&nbsp;<a href="#introduction">Introduction</a></h1>
     716         <p id="rfc.section.1.p.1">This document defines HTTP/1.1 request and response semantics. Each HTTP message, as defined in <a href="#Part1" id="rfc.xref.Part1.1"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, is in the form of either a request or a response. An HTTP server listens on a connection for HTTP requests and responds
     717            to each request, in the order received on that connection, with one or more HTTP response messages. This document defines
     718            the commonly agreed upon semantics of the HTTP uniform interface, the intentions defined by each request method, and the various
     719            response messages that might be expected as a result of applying that method to the target resource.
     720         </p>
     721         <p id="rfc.section.1.p.2">This document is currently disorganized in order to minimize the changes between drafts and enable reviewers to see the smaller
     722            errata changes. A future draft will reorganize the sections to better reflect the content. In particular, the sections will
     723            be ordered according to the typical processing of an HTTP request message (after message parsing): resource mapping, methods,
     724            request modifying header fields, response status, status modifying header fields, and resource metadata. The current mess
     725            reflects how widely dispersed these topics and associated requirements had become in <a href="#RFC2616" id="rfc.xref.RFC2616.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>.
     726         </p>
     727         <div id="intro.requirements">
     728            <h2 id="rfc.section.1.1"><a href="#rfc.section.1.1">1.1</a>&nbsp;<a href="#intro.requirements">Requirements</a></h2>
     729            <p id="rfc.section.1.1.p.1">The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL"
     730               in this document are to be interpreted as described in <a href="#RFC2119" id="rfc.xref.RFC2119.1"><cite title="Key words for use in RFCs to Indicate Requirement Levels">[RFC2119]</cite></a>.
     731            </p>
     732            <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the "MUST" or "REQUIRED" level requirements for the
     733               protocols it implements. An implementation that satisfies all the "MUST" or "REQUIRED" level and all the "SHOULD" level requirements
     734               for its protocols is said to be "unconditionally compliant"; one that satisfies all the "MUST" level requirements but not
     735               all the "SHOULD" level requirements for its protocols is said to be "conditionally compliant".
     736            </p>
     737         </div>
     738         <div id="notation">
     739            <h2 id="rfc.section.1.2"><a href="#rfc.section.1.2">1.2</a>&nbsp;<a href="#notation">Syntax Notation</a></h2>
     740            <p id="rfc.section.1.2.p.1">This specification uses the ABNF syntax defined in <a href="p1-messaging.html#notation" title="Syntax Notation">Section 1.2</a> of <a href="#Part1" id="rfc.xref.Part1.2"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> (which extends the syntax defined in <a href="#RFC5234" id="rfc.xref.RFC5234.1"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a> with a list rule). <a href="#collected.abnf" title="Collected ABNF">Appendix&nbsp;B</a> shows the collected ABNF, with the list rule expanded.
     741            </p>
     742            <p id="rfc.section.1.2.p.2">The following core rules are included by reference, as defined in <a href="#RFC5234" id="rfc.xref.RFC5234.2"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>, <a href="https://tools.ietf.org/html/rfc5234#appendix-B.1">Appendix B.1</a>: ALPHA (letters), CR (carriage return), CRLF (CR LF), CTL (controls), DIGIT (decimal 0-9), DQUOTE (double quote), HEXDIG
     743               (hexadecimal 0-9/A-F/a-f), LF (line feed), OCTET (any 8-bit sequence of data), SP (space), VCHAR (any visible USASCII character),
     744               and WSP (whitespace).
     745            </p>
     746            <div id="core.rules">
     747               <h3 id="rfc.section.1.2.1"><a href="#rfc.section.1.2.1">1.2.1</a>&nbsp;<a href="#core.rules">Core Rules</a></h3>
     748               <p id="rfc.section.1.2.1.p.1">The core rules below are defined in <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a> of <a href="#Part1" id="rfc.xref.Part1.3"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>:
     749               </p>
     750               <div id="rfc.figure.u.1"></div><pre class="inline">  <a href="#core.rules" class="smpl">quoted-string</a> = &lt;quoted-string, defined in <a href="#Part1" id="rfc.xref.Part1.4"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
    739751  <a href="#core.rules" class="smpl">token</a>         = &lt;token, defined in <a href="#Part1" id="rfc.xref.Part1.5"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
    740752  <a href="#core.rules" class="smpl">OWS</a>           = &lt;OWS, defined in <a href="#Part1" id="rfc.xref.Part1.6"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
    741753  <a href="#core.rules" class="smpl">RWS</a>           = &lt;RWS, defined in <a href="#Part1" id="rfc.xref.Part1.7"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
    742754  <a href="#core.rules" class="smpl">obs-text</a>      = &lt;obs-text, defined in <a href="#Part1" id="rfc.xref.Part1.8"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 1.2.2</a>&gt;
    743 </pre><h3 id="rfc.section.1.2.2"><a href="#rfc.section.1.2.2">1.2.2</a>&nbsp;<a id="abnf.dependencies" href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></h3>
    744       <p id="rfc.section.1.2.2.p.1">The ABNF rules below are defined in other parts:</p>
    745       <div id="rfc.figure.u.2"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">absolute-URI</a>  = &lt;absolute-URI, defined in <a href="#Part1" id="rfc.xref.Part1.9"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#uri" title="Uniform Resource Identifiers">Section 2.7</a>&gt;
     755</pre></div>
     756            <div id="abnf.dependencies">
     757               <h3 id="rfc.section.1.2.2"><a href="#rfc.section.1.2.2">1.2.2</a>&nbsp;<a href="#abnf.dependencies">ABNF Rules defined in other Parts of the Specification</a></h3>
     758               <p id="rfc.section.1.2.2.p.1">The ABNF rules below are defined in other parts:</p>
     759               <div id="rfc.figure.u.2"></div><pre class="inline">  <a href="#abnf.dependencies" class="smpl">absolute-URI</a>  = &lt;absolute-URI, defined in <a href="#Part1" id="rfc.xref.Part1.9"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#uri" title="Uniform Resource Identifiers">Section 2.7</a>&gt;
    746760  <a href="#abnf.dependencies" class="smpl">comment</a>       = &lt;comment, defined in <a href="#Part1" id="rfc.xref.Part1.10"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a>&gt;
    747761  <a href="#abnf.dependencies" class="smpl">HTTP-date</a>     = &lt;HTTP-date, defined in <a href="#Part1" id="rfc.xref.Part1.11"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#date.time.formats.full.date" title="Date/Time Formats: Full Date">Section 6.1</a>&gt;
     
    749763  <a href="#abnf.dependencies" class="smpl">product</a>       = &lt;product, defined in <a href="#Part1" id="rfc.xref.Part1.13"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#product.tokens" title="Product Tokens">Section 6.3</a>&gt;
    750764  <a href="#abnf.dependencies" class="smpl">URI-reference</a> = &lt;URI-reference, defined in <a href="#Part1" id="rfc.xref.Part1.14"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#uri" title="Uniform Resource Identifiers">Section 2.7</a>&gt;
    751 </pre><h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a id="method" href="#method">Method</a></h1>
    752       <p id="rfc.section.2.p.1">The Method token indicates the request method to be performed on the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.15"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). The method is case-sensitive.
    753       </p>
    754       <div id="rfc.figure.u.3"></div><pre class="inline"><span id="rfc.iref.g.1"></span>  <a href="#method" class="smpl">Method</a>         = <a href="#core.rules" class="smpl">token</a>
     765</pre></div>
     766         </div>
     767      </div>
     768      <div id="method">
     769         <h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a>&nbsp;<a href="#method">Method</a></h1>
     770         <p id="rfc.section.2.p.1">The Method token indicates the request method to be performed on the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.15"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). The method is case-sensitive.
     771         </p>
     772         <div id="rfc.figure.u.3"></div><pre class="inline"><span id="rfc.iref.g.1"></span>  <a href="#method" class="smpl">Method</a>         = <a href="#core.rules" class="smpl">token</a>
    755773</pre><p id="rfc.section.2.p.3">The list of methods allowed by a resource can be specified in an Allow header field (<a href="#header.allow" id="rfc.xref.header.allow.1" title="Allow">Section&nbsp;9.1</a>). The status code of the response always notifies the client whether a method is currently allowed on a resource, since the
    756          set of allowed methods can change dynamically. An origin server <em class="bcp14">SHOULD</em> respond with the status code 405 (Method Not Allowed) if the method is known by the origin server but not allowed for the
    757          resource, and 501 (Not Implemented) if the method is unrecognized or not implemented by the origin server. The methods GET
    758          and HEAD <em class="bcp14">MUST</em> be supported by all general-purpose servers. All other methods are <em class="bcp14">OPTIONAL</em>; however, if the above methods are implemented, they <em class="bcp14">MUST</em> be implemented with the same semantics as those specified in <a href="#method.definitions" title="Method Definitions">Section&nbsp;7</a>.
    759       </p>
    760       <h2 id="rfc.section.2.1"><a href="#rfc.section.2.1">2.1</a>&nbsp;<a id="overview.of.methods" href="#overview.of.methods">Overview of Methods</a></h2>
    761       <p id="rfc.section.2.1.p.1">The methods listed below are defined in <a href="#method.definitions" title="Method Definitions">Section&nbsp;7</a>.
    762       </p>
    763       <div id="rfc.table.u.1">
    764          <table class="tt full left" cellpadding="3" cellspacing="0">
    765             <thead>
    766                <tr>
    767                   <th>Method Name</th>
    768                   <th>Defined in...</th>
    769                </tr>
    770             </thead>
    771             <tbody>
    772                <tr>
    773                   <td class="left">OPTIONS</td>
    774                   <td class="left"><a href="#OPTIONS" id="rfc.xref.OPTIONS.1" title="OPTIONS">Section&nbsp;7.2</a></td>
    775                </tr>
    776                <tr>
    777                   <td class="left">GET</td>
    778                   <td class="left"><a href="#GET" id="rfc.xref.GET.1" title="GET">Section&nbsp;7.3</a></td>
    779                </tr>
    780                <tr>
    781                   <td class="left">HEAD</td>
    782                   <td class="left"><a href="#HEAD" id="rfc.xref.HEAD.1" title="HEAD">Section&nbsp;7.4</a></td>
    783                </tr>
    784                <tr>
    785                   <td class="left">POST</td>
    786                   <td class="left"><a href="#POST" id="rfc.xref.POST.1" title="POST">Section&nbsp;7.5</a></td>
    787                </tr>
    788                <tr>
    789                   <td class="left">PUT</td>
    790                   <td class="left"><a href="#PUT" id="rfc.xref.PUT.1" title="PUT">Section&nbsp;7.6</a></td>
    791                </tr>
    792                <tr>
    793                   <td class="left">DELETE</td>
    794                   <td class="left"><a href="#DELETE" id="rfc.xref.DELETE.1" title="DELETE">Section&nbsp;7.7</a></td>
    795                </tr>
    796                <tr>
    797                   <td class="left">TRACE</td>
    798                   <td class="left"><a href="#TRACE" id="rfc.xref.TRACE.1" title="TRACE">Section&nbsp;7.8</a></td>
    799                </tr>
    800                <tr>
    801                   <td class="left">CONNECT</td>
    802                   <td class="left"><a href="#CONNECT" id="rfc.xref.CONNECT.1" title="CONNECT">Section&nbsp;7.9</a></td>
    803                </tr>
    804             </tbody>
    805          </table>
     774            set of allowed methods can change dynamically. An origin server <em class="bcp14">SHOULD</em> respond with the status code 405 (Method Not Allowed) if the method is known by the origin server but not allowed for the
     775            resource, and 501 (Not Implemented) if the method is unrecognized or not implemented by the origin server. The methods GET
     776            and HEAD <em class="bcp14">MUST</em> be supported by all general-purpose servers. All other methods are <em class="bcp14">OPTIONAL</em>; however, if the above methods are implemented, they <em class="bcp14">MUST</em> be implemented with the same semantics as those specified in <a href="#method.definitions" title="Method Definitions">Section&nbsp;7</a>.
     777         </p>
     778         <div id="overview.of.methods">
     779            <h2 id="rfc.section.2.1"><a href="#rfc.section.2.1">2.1</a>&nbsp;<a href="#overview.of.methods">Overview of Methods</a></h2>
     780            <p id="rfc.section.2.1.p.1">The methods listed below are defined in <a href="#method.definitions" title="Method Definitions">Section&nbsp;7</a>.
     781            </p>
     782            <div id="rfc.table.u.1">
     783               <table class="tt full left" cellpadding="3" cellspacing="0">
     784                  <thead>
     785                     <tr>
     786                        <th>Method Name</th>
     787                        <th>Defined in...</th>
     788                     </tr>
     789                  </thead>
     790                  <tbody>
     791                     <tr>
     792                        <td class="left">OPTIONS</td>
     793                        <td class="left"><a href="#OPTIONS" id="rfc.xref.OPTIONS.1" title="OPTIONS">Section&nbsp;7.2</a></td>
     794                     </tr>
     795                     <tr>
     796                        <td class="left">GET</td>
     797                        <td class="left"><a href="#GET" id="rfc.xref.GET.1" title="GET">Section&nbsp;7.3</a></td>
     798                     </tr>
     799                     <tr>
     800                        <td class="left">HEAD</td>
     801                        <td class="left"><a href="#HEAD" id="rfc.xref.HEAD.1" title="HEAD">Section&nbsp;7.4</a></td>
     802                     </tr>
     803                     <tr>
     804                        <td class="left">POST</td>
     805                        <td class="left"><a href="#POST" id="rfc.xref.POST.1" title="POST">Section&nbsp;7.5</a></td>
     806                     </tr>
     807                     <tr>
     808                        <td class="left">PUT</td>
     809                        <td class="left"><a href="#PUT" id="rfc.xref.PUT.1" title="PUT">Section&nbsp;7.6</a></td>
     810                     </tr>
     811                     <tr>
     812                        <td class="left">DELETE</td>
     813                        <td class="left"><a href="#DELETE" id="rfc.xref.DELETE.1" title="DELETE">Section&nbsp;7.7</a></td>
     814                     </tr>
     815                     <tr>
     816                        <td class="left">TRACE</td>
     817                        <td class="left"><a href="#TRACE" id="rfc.xref.TRACE.1" title="TRACE">Section&nbsp;7.8</a></td>
     818                     </tr>
     819                     <tr>
     820                        <td class="left">CONNECT</td>
     821                        <td class="left"><a href="#CONNECT" id="rfc.xref.CONNECT.1" title="CONNECT">Section&nbsp;7.9</a></td>
     822                     </tr>
     823                  </tbody>
     824               </table>
     825            </div>
     826            <p id="rfc.section.2.1.p.2">Note that this list is not exhaustive — it does not include request methods defined in other specifications.</p>
     827         </div>
     828         <div id="method.registry">
     829            <h2 id="rfc.section.2.2"><a href="#rfc.section.2.2">2.2</a>&nbsp;<a href="#method.registry">Method Registry</a></h2>
     830            <p id="rfc.section.2.2.p.1">The HTTP Method Registry defines the name space for the Method token in the Request line of an HTTP request.</p>
     831            <p id="rfc.section.2.2.p.2">Registrations <em class="bcp14">MUST</em> include the following fields:
     832            </p>
     833            <ul>
     834               <li>Method Name (see <a href="#method" title="Method">Section&nbsp;2</a>)
     835               </li>
     836               <li>Safe ("yes" or "no", see <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>)
     837               </li>
     838               <li>Pointer to specification text</li>
     839            </ul>
     840            <p id="rfc.section.2.2.p.3">Values to be added to this name space are subject to IETF review (<a href="#RFC5226" id="rfc.xref.RFC5226.1"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="https://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
     841            </p>
     842            <p id="rfc.section.2.2.p.4">The registry itself is maintained at &lt;<a href="http://www.iana.org/assignments/http-methods">http://www.iana.org/assignments/http-methods</a>&gt;.
     843            </p>
     844            <div id="considerations.for.new.methods">
     845               <h3 id="rfc.section.2.2.1"><a href="#rfc.section.2.2.1">2.2.1</a>&nbsp;<a href="#considerations.for.new.methods">Considerations for New Methods</a></h3>
     846               <p id="rfc.section.2.2.1.p.1">When it is necessary to express new semantics for a HTTP request that aren't specific to a single application or media type,
     847                  and currently defined methods are inadequate, it may be appropriate to register a new method.
     848               </p>
     849               <p id="rfc.section.2.2.1.p.2">HTTP methods are generic; that is, they are potentially applicable to any resource, not just one particular media type, "type"
     850                  of resource, or application. As such, it is preferred that new HTTP methods be registered in a document that isn't specific
     851                  to a single application, so that this is clear.
     852               </p>
     853               <p id="rfc.section.2.2.1.p.3">Due to the parsing rules defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.16"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, definitions of HTTP methods cannot prohibit the presence of a message-body on either the request or the response message
     854                  (with responses to HEAD requests being the single exception). Definitions of new methods cannot change this rule, but they
     855                  can specify that only zero-length bodies (as opposed to absent bodies) are allowed.
     856               </p>
     857               <p id="rfc.section.2.2.1.p.4">New method definitions need to indicate whether they are safe (<a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>), what semantics (if any) the request body has, and whether they are idempotent (<a href="#idempotent.methods" title="Idempotent Methods">Section&nbsp;7.1.2</a>). They also need to state whether they can be cached (<a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>); in particular what conditions a cache may store the response, and under what conditions such a stored response may be used
     858                  to satisfy a subsequent request.
     859               </p>
     860            </div>
     861         </div>
    806862      </div>
    807       <p id="rfc.section.2.1.p.2">Note that this list is not exhaustive — it does not include request methods defined in other specifications.</p>
    808       <h2 id="rfc.section.2.2"><a href="#rfc.section.2.2">2.2</a>&nbsp;<a id="method.registry" href="#method.registry">Method Registry</a></h2>
    809       <p id="rfc.section.2.2.p.1">The HTTP Method Registry defines the name space for the Method token in the Request line of an HTTP request.</p>
    810       <p id="rfc.section.2.2.p.2">Registrations <em class="bcp14">MUST</em> include the following fields:
    811       </p>
    812       <ul>
    813          <li>Method Name (see <a href="#method" title="Method">Section&nbsp;2</a>)
    814          </li>
    815          <li>Safe ("yes" or "no", see <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>)
    816          </li>
    817          <li>Pointer to specification text</li>
    818       </ul>
    819       <p id="rfc.section.2.2.p.3">Values to be added to this name space are subject to IETF review (<a href="#RFC5226" id="rfc.xref.RFC5226.1"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
    820       </p>
    821       <p id="rfc.section.2.2.p.4">The registry itself is maintained at &lt;<a href="http://www.iana.org/assignments/http-methods">http://www.iana.org/assignments/http-methods</a>&gt;.
    822       </p>
    823       <h3 id="rfc.section.2.2.1"><a href="#rfc.section.2.2.1">2.2.1</a>&nbsp;<a id="considerations.for.new.methods" href="#considerations.for.new.methods">Considerations for New Methods</a></h3>
    824       <p id="rfc.section.2.2.1.p.1">When it is necessary to express new semantics for a HTTP request that aren't specific to a single application or media type,
    825          and currently defined methods are inadequate, it may be appropriate to register a new method.
    826       </p>
    827       <p id="rfc.section.2.2.1.p.2">HTTP methods are generic; that is, they are potentially applicable to any resource, not just one particular media type, "type"
    828          of resource, or application. As such, it is preferred that new HTTP methods be registered in a document that isn't specific
    829          to a single application, so that this is clear.
    830       </p>
    831       <p id="rfc.section.2.2.1.p.3">Due to the parsing rules defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.16"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, definitions of HTTP methods cannot prohibit the presence of a message-body on either the request or the response message
    832          (with responses to HEAD requests being the single exception). Definitions of new methods cannot change this rule, but they
    833          can specify that only zero-length bodies (as opposed to absent bodies) are allowed.
    834       </p>
    835       <p id="rfc.section.2.2.1.p.4">New method definitions need to indicate whether they are safe (<a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>), what semantics (if any) the request body has, and whether they are idempotent (<a href="#idempotent.methods" title="Idempotent Methods">Section&nbsp;7.1.2</a>). They also need to state whether they can be cached (<a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>); in particular what conditions a cache may store the response, and under what conditions such a stored response may be used
    836          to satisfy a subsequent request.
    837       </p>
    838       <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a>&nbsp;<a id="request.header.fields" href="#request.header.fields">Request Header Fields</a></h1>
    839       <p id="rfc.section.3.p.1">The request header fields allow the client to pass additional information about the request, and about the client itself,
    840          to the server. These fields act as request modifiers, with semantics equivalent to the parameters on a programming language
    841          method invocation.
    842       </p>
    843       <div id="rfc.table.u.2">
    844          <table class="tt full left" cellpadding="3" cellspacing="0">
    845             <thead>
    846                <tr>
    847                   <th>Header Field Name</th>
    848                   <th>Defined in...</th>
    849                </tr>
    850             </thead>
    851             <tbody>
    852                <tr>
    853                   <td class="left">Accept</td>
    854                   <td class="left"><a href="p3-payload.html#header.accept" title="Accept">Section 6.1</a> of <a href="#Part3" id="rfc.xref.Part3.1"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
    855                </tr>
    856                <tr>
    857                   <td class="left">Accept-Charset</td>
    858                   <td class="left"><a href="p3-payload.html#header.accept-charset" title="Accept-Charset">Section 6.2</a> of <a href="#Part3" id="rfc.xref.Part3.2"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
    859                </tr>
    860                <tr>
    861                   <td class="left">Accept-Encoding</td>
    862                   <td class="left"><a href="p3-payload.html#header.accept-encoding" title="Accept-Encoding">Section 6.3</a> of <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
    863                </tr>
    864                <tr>
    865                   <td class="left">Accept-Language</td>
    866                   <td class="left"><a href="p3-payload.html#header.accept-language" title="Accept-Language">Section 6.4</a> of <a href="#Part3" id="rfc.xref.Part3.4"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
    867                </tr>
    868                <tr>
    869                   <td class="left">Authorization</td>
    870                   <td class="left"><a href="p7-auth.html#header.authorization" title="Authorization">Section 4.1</a> of <a href="#Part7" id="rfc.xref.Part7.1"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
    871                </tr>
    872                <tr>
    873                   <td class="left">Expect</td>
    874                   <td class="left"><a href="#header.expect" id="rfc.xref.header.expect.1" title="Expect">Section&nbsp;9.2</a></td>
    875                </tr>
    876                <tr>
    877                   <td class="left">From</td>
    878                   <td class="left"><a href="#header.from" id="rfc.xref.header.from.1" title="From">Section&nbsp;9.3</a></td>
    879                </tr>
    880                <tr>
    881                   <td class="left">Host</td>
    882                   <td class="left"><a href="p1-messaging.html#header.host" title="Host">Section 9.4</a> of <a href="#Part1" id="rfc.xref.Part1.17"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a></td>
    883                </tr>
    884                <tr>
    885                   <td class="left">If-Match</td>
    886                   <td class="left"><a href="p4-conditional.html#header.if-match" title="If-Match">Section 3.1</a> of <a href="#Part4" id="rfc.xref.Part4.1"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
    887                </tr>
    888                <tr>
    889                   <td class="left">If-Modified-Since</td>
    890                   <td class="left"><a href="p4-conditional.html#header.if-modified-since" title="If-Modified-Since">Section 3.3</a> of <a href="#Part4" id="rfc.xref.Part4.2"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
    891                </tr>
    892                <tr>
    893                   <td class="left">If-None-Match</td>
    894                   <td class="left"><a href="p4-conditional.html#header.if-none-match" title="If-None-Match">Section 3.2</a> of <a href="#Part4" id="rfc.xref.Part4.3"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
    895                </tr>
    896                <tr>
    897                   <td class="left">If-Range</td>
    898                   <td class="left"><a href="p5-range.html#header.if-range" title="If-Range">Section 5.3</a> of <a href="#Part5" id="rfc.xref.Part5.1"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
    899                </tr>
    900                <tr>
    901                   <td class="left">If-Unmodified-Since</td>
    902                   <td class="left"><a href="p4-conditional.html#header.if-unmodified-since" title="If-Unmodified-Since">Section 3.4</a> of <a href="#Part4" id="rfc.xref.Part4.4"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
    903                </tr>
    904                <tr>
    905                   <td class="left">Max-Forwards</td>
    906                   <td class="left"><a href="#header.max-forwards" id="rfc.xref.header.max-forwards.1" title="Max-Forwards">Section&nbsp;9.5</a></td>
    907                </tr>
    908                <tr>
    909                   <td class="left">Proxy-Authorization</td>
    910                   <td class="left"><a href="p7-auth.html#header.proxy-authorization" title="Proxy-Authorization">Section 4.3</a> of <a href="#Part7" id="rfc.xref.Part7.2"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
    911                </tr>
    912                <tr>
    913                   <td class="left">Range</td>
    914                   <td class="left"><a href="p5-range.html#header.range" title="Range">Section 5.4</a> of <a href="#Part5" id="rfc.xref.Part5.2"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
    915                </tr>
    916                <tr>
    917                   <td class="left">Referer</td>
    918                   <td class="left"><a href="#header.referer" id="rfc.xref.header.referer.1" title="Referer">Section&nbsp;9.6</a></td>
    919                </tr>
    920                <tr>
    921                   <td class="left">TE</td>
    922                   <td class="left"><a href="p1-messaging.html#header.te" title="TE">Section 9.5</a> of <a href="#Part1" id="rfc.xref.Part1.18"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a></td>
    923                </tr>
    924                <tr>
    925                   <td class="left">User-Agent</td>
    926                   <td class="left"><a href="#header.user-agent" id="rfc.xref.header.user-agent.1" title="User-Agent">Section&nbsp;9.9</a></td>
    927                </tr>
    928             </tbody>
    929          </table>
     863      <div id="request.header.fields">
     864         <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a>&nbsp;<a href="#request.header.fields">Request Header Fields</a></h1>
     865         <p id="rfc.section.3.p.1">The request header fields allow the client to pass additional information about the request, and about the client itself,
     866            to the server. These fields act as request modifiers, with semantics equivalent to the parameters on a programming language
     867            method invocation.
     868         </p>
     869         <div id="rfc.table.u.2">
     870            <table class="tt full left" cellpadding="3" cellspacing="0">
     871               <thead>
     872                  <tr>
     873                     <th>Header Field Name</th>
     874                     <th>Defined in...</th>
     875                  </tr>
     876               </thead>
     877               <tbody>
     878                  <tr>
     879                     <td class="left">Accept</td>
     880                     <td class="left"><a href="p3-payload.html#header.accept" title="Accept">Section 6.1</a> of <a href="#Part3" id="rfc.xref.Part3.1"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
     881                  </tr>
     882                  <tr>
     883                     <td class="left">Accept-Charset</td>
     884                     <td class="left"><a href="p3-payload.html#header.accept-charset" title="Accept-Charset">Section 6.2</a> of <a href="#Part3" id="rfc.xref.Part3.2"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
     885                  </tr>
     886                  <tr>
     887                     <td class="left">Accept-Encoding</td>
     888                     <td class="left"><a href="p3-payload.html#header.accept-encoding" title="Accept-Encoding">Section 6.3</a> of <a href="#Part3" id="rfc.xref.Part3.3"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
     889                  </tr>
     890                  <tr>
     891                     <td class="left">Accept-Language</td>
     892                     <td class="left"><a href="p3-payload.html#header.accept-language" title="Accept-Language">Section 6.4</a> of <a href="#Part3" id="rfc.xref.Part3.4"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a></td>
     893                  </tr>
     894                  <tr>
     895                     <td class="left">Authorization</td>
     896                     <td class="left"><a href="p7-auth.html#header.authorization" title="Authorization">Section 4.1</a> of <a href="#Part7" id="rfc.xref.Part7.1"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
     897                  </tr>
     898                  <tr>
     899                     <td class="left">Expect</td>
     900                     <td class="left"><a href="#header.expect" id="rfc.xref.header.expect.1" title="Expect">Section&nbsp;9.2</a></td>
     901                  </tr>
     902                  <tr>
     903                     <td class="left">From</td>
     904                     <td class="left"><a href="#header.from" id="rfc.xref.header.from.1" title="From">Section&nbsp;9.3</a></td>
     905                  </tr>
     906                  <tr>
     907                     <td class="left">Host</td>
     908                     <td class="left"><a href="p1-messaging.html#header.host" title="Host">Section 9.4</a> of <a href="#Part1" id="rfc.xref.Part1.17"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a></td>
     909                  </tr>
     910                  <tr>
     911                     <td class="left">If-Match</td>
     912                     <td class="left"><a href="p4-conditional.html#header.if-match" title="If-Match">Section 3.1</a> of <a href="#Part4" id="rfc.xref.Part4.1"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
     913                  </tr>
     914                  <tr>
     915                     <td class="left">If-Modified-Since</td>
     916                     <td class="left"><a href="p4-conditional.html#header.if-modified-since" title="If-Modified-Since">Section 3.3</a> of <a href="#Part4" id="rfc.xref.Part4.2"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
     917                  </tr>
     918                  <tr>
     919                     <td class="left">If-None-Match</td>
     920                     <td class="left"><a href="p4-conditional.html#header.if-none-match" title="If-None-Match">Section 3.2</a> of <a href="#Part4" id="rfc.xref.Part4.3"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
     921                  </tr>
     922                  <tr>
     923                     <td class="left">If-Range</td>
     924                     <td class="left"><a href="p5-range.html#header.if-range" title="If-Range">Section 5.3</a> of <a href="#Part5" id="rfc.xref.Part5.1"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
     925                  </tr>
     926                  <tr>
     927                     <td class="left">If-Unmodified-Since</td>
     928                     <td class="left"><a href="p4-conditional.html#header.if-unmodified-since" title="If-Unmodified-Since">Section 3.4</a> of <a href="#Part4" id="rfc.xref.Part4.4"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
     929                  </tr>
     930                  <tr>
     931                     <td class="left">Max-Forwards</td>
     932                     <td class="left"><a href="#header.max-forwards" id="rfc.xref.header.max-forwards.1" title="Max-Forwards">Section&nbsp;9.5</a></td>
     933                  </tr>
     934                  <tr>
     935                     <td class="left">Proxy-Authorization</td>
     936                     <td class="left"><a href="p7-auth.html#header.proxy-authorization" title="Proxy-Authorization">Section 4.3</a> of <a href="#Part7" id="rfc.xref.Part7.2"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
     937                  </tr>
     938                  <tr>
     939                     <td class="left">Range</td>
     940                     <td class="left"><a href="p5-range.html#header.range" title="Range">Section 5.4</a> of <a href="#Part5" id="rfc.xref.Part5.2"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
     941                  </tr>
     942                  <tr>
     943                     <td class="left">Referer</td>
     944                     <td class="left"><a href="#header.referer" id="rfc.xref.header.referer.1" title="Referer">Section&nbsp;9.6</a></td>
     945                  </tr>
     946                  <tr>
     947                     <td class="left">TE</td>
     948                     <td class="left"><a href="p1-messaging.html#header.te" title="TE">Section 9.5</a> of <a href="#Part1" id="rfc.xref.Part1.18"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a></td>
     949                  </tr>
     950                  <tr>
     951                     <td class="left">User-Agent</td>
     952                     <td class="left"><a href="#header.user-agent" id="rfc.xref.header.user-agent.1" title="User-Agent">Section&nbsp;9.9</a></td>
     953                  </tr>
     954               </tbody>
     955            </table>
     956         </div>
    930957      </div>
    931       <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a id="status.code.and.reason.phrase" href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h1>
    932       <p id="rfc.section.4.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request.</p>
    933       <p id="rfc.section.4.p.2">The Reason-Phrase is intended to give a short textual description of the Status-Code and is intended for a human user. The
    934          client does not need to examine or display the Reason-Phrase.
    935       </p>
    936       <div id="rfc.figure.u.4"></div><pre class="inline"><span id="rfc.iref.g.2"></span><span id="rfc.iref.g.3"></span><span id="rfc.iref.g.4"></span>  <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a>    = 3<a href="#notation" class="smpl">DIGIT</a>
     958      <div id="status.code.and.reason.phrase">
     959         <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a>&nbsp;<a href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h1>
     960         <p id="rfc.section.4.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request.</p>
     961         <p id="rfc.section.4.p.2">The Reason-Phrase is intended to give a short textual description of the Status-Code and is intended for a human user. The
     962            client does not need to examine or display the Reason-Phrase.
     963         </p>
     964         <div id="rfc.figure.u.4"></div><pre class="inline"><span id="rfc.iref.g.2"></span><span id="rfc.iref.g.3"></span><span id="rfc.iref.g.4"></span>  <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a>    = 3<a href="#notation" class="smpl">DIGIT</a>
    937965  <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a>  = *( <a href="#notation" class="smpl">WSP</a> / <a href="#notation" class="smpl">VCHAR</a> / <a href="#core.rules" class="smpl">obs-text</a> )
    938966</pre><p id="rfc.section.4.p.4">HTTP status codes are extensible. HTTP applications are not required to understand the meaning of all registered status codes,
    939          though such understanding is obviously desirable. However, applications <em class="bcp14">MUST</em> understand the class of any status code, as indicated by the first digit, and treat any unrecognized response as being equivalent
    940          to the x00 status code of that class, with the exception that an unrecognized response <em class="bcp14">MUST NOT</em> be cached. For example, if an unrecognized status code of 431 is received by the client, it can safely assume that there was
    941          something wrong with its request and treat the response as if it had received a 400 status code. In such cases, user agents <em class="bcp14">SHOULD</em> present to the user the representation enclosed with the response, since that representation is likely to include human-readable
    942          information which will explain the unusual status.
    943       </p>
    944       <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a id="overview.of.status.codes" href="#overview.of.status.codes">Overview of Status Codes</a></h2>
    945       <p id="rfc.section.4.1.p.1">The status codes listed below are defined in <a href="#status.codes" title="Status Code Definitions">Section&nbsp;8</a> of this specification, <a href="p4-conditional.html#status.code.definitions" title="Status Code Definitions">Section 4</a> of <a href="#Part4" id="rfc.xref.Part4.5"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>, <a href="p5-range.html#status.code.definitions" title="Status Code Definitions">Section 3</a> of <a href="#Part5" id="rfc.xref.Part5.3"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>, and <a href="p7-auth.html#status.code.definitions" title="Status Code Definitions">Section 3</a> of <a href="#Part7" id="rfc.xref.Part7.3"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a>. The reason phrases listed here are only recommendations — they can be replaced by local equivalents without affecting the
    946          protocol.
    947       </p>
    948       <div id="rfc.table.u.3">
    949          <table class="tt full left" cellpadding="3" cellspacing="0">
    950             <thead>
    951                <tr>
    952                   <th>Status-Code</th>
    953                   <th>Reason-Phrase</th>
    954                   <th>Defined in...</th>
    955                </tr>
    956             </thead>
    957             <tbody>
    958                <tr>
    959                   <td class="left">100</td>
    960                   <td class="left">Continue</td>
    961                   <td class="left"><a href="#status.100" id="rfc.xref.status.100.1" title="100 Continue">Section&nbsp;8.1.1</a></td>
    962                </tr>
    963                <tr>
    964                   <td class="left">101</td>
    965                   <td class="left">Switching Protocols</td>
    966                   <td class="left"><a href="#status.101" id="rfc.xref.status.101.1" title="101 Switching Protocols">Section&nbsp;8.1.2</a></td>
    967                </tr>
    968                <tr>
    969                   <td class="left">200</td>
    970                   <td class="left">OK</td>
    971                   <td class="left"><a href="#status.200" id="rfc.xref.status.200.1" title="200 OK">Section&nbsp;8.2.1</a></td>
    972                </tr>
    973                <tr>
    974                   <td class="left">201</td>
    975                   <td class="left">Created</td>
    976                   <td class="left"><a href="#status.201" id="rfc.xref.status.201.1" title="201 Created">Section&nbsp;8.2.2</a></td>
    977                </tr>
    978                <tr>
    979                   <td class="left">202</td>
    980                   <td class="left">Accepted</td>
    981                   <td class="left"><a href="#status.202" id="rfc.xref.status.202.1" title="202 Accepted">Section&nbsp;8.2.3</a></td>
    982                </tr>
    983                <tr>
    984                   <td class="left">203</td>
    985                   <td class="left">Non-Authoritative Information</td>
    986                   <td class="left"><a href="#status.203" id="rfc.xref.status.203.1" title="203 Non-Authoritative Information">Section&nbsp;8.2.4</a></td>
    987                </tr>
    988                <tr>
    989                   <td class="left">204</td>
    990                   <td class="left">No Content</td>
    991                   <td class="left"><a href="#status.204" id="rfc.xref.status.204.1" title="204 No Content">Section&nbsp;8.2.5</a></td>
    992                </tr>
    993                <tr>
    994                   <td class="left">205</td>
    995                   <td class="left">Reset Content</td>
    996                   <td class="left"><a href="#status.205" id="rfc.xref.status.205.1" title="205 Reset Content">Section&nbsp;8.2.6</a></td>
    997                </tr>
    998                <tr>
    999                   <td class="left">206</td>
    1000                   <td class="left">Partial Content</td>
    1001                   <td class="left"><a href="p5-range.html#status.206" title="206 Partial Content">Section 3.1</a> of <a href="#Part5" id="rfc.xref.Part5.4"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
    1002                </tr>
    1003                <tr>
    1004                   <td class="left">300</td>
    1005                   <td class="left">Multiple Choices</td>
    1006                   <td class="left"><a href="#status.300" id="rfc.xref.status.300.1" title="300 Multiple Choices">Section&nbsp;8.3.1</a></td>
    1007                </tr>
    1008                <tr>
    1009                   <td class="left">301</td>
    1010                   <td class="left">Moved Permanently</td>
    1011                   <td class="left"><a href="#status.301" id="rfc.xref.status.301.1" title="301 Moved Permanently">Section&nbsp;8.3.2</a></td>
    1012                </tr>
    1013                <tr>
    1014                   <td class="left">302</td>
    1015                   <td class="left">Found</td>
    1016                   <td class="left"><a href="#status.302" id="rfc.xref.status.302.1" title="302 Found">Section&nbsp;8.3.3</a></td>
    1017                </tr>
    1018                <tr>
    1019                   <td class="left">303</td>
    1020                   <td class="left">See Other</td>
    1021                   <td class="left"><a href="#status.303" id="rfc.xref.status.303.1" title="303 See Other">Section&nbsp;8.3.4</a></td>
    1022                </tr>
    1023                <tr>
    1024                   <td class="left">304</td>
    1025                   <td class="left">Not Modified</td>
    1026                   <td class="left"><a href="p4-conditional.html#status.304" title="304 Not Modified">Section 4.1</a> of <a href="#Part4" id="rfc.xref.Part4.6"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
    1027                </tr>
    1028                <tr>
    1029                   <td class="left">305</td>
    1030                   <td class="left">Use Proxy</td>
    1031                   <td class="left"><a href="#status.305" id="rfc.xref.status.305.1" title="305 Use Proxy">Section&nbsp;8.3.6</a></td>
    1032                </tr>
    1033                <tr>
    1034                   <td class="left">307</td>
    1035                   <td class="left">Temporary Redirect</td>
    1036                   <td class="left"><a href="#status.307" id="rfc.xref.status.307.1" title="307 Temporary Redirect">Section&nbsp;8.3.8</a></td>
    1037                </tr>
    1038                <tr>
    1039                   <td class="left">400</td>
    1040                   <td class="left">Bad Request</td>
    1041                   <td class="left"><a href="#status.400" id="rfc.xref.status.400.1" title="400 Bad Request">Section&nbsp;8.4.1</a></td>
    1042                </tr>
    1043                <tr>
    1044                   <td class="left">401</td>
    1045                   <td class="left">Unauthorized</td>
    1046                   <td class="left"><a href="p7-auth.html#status.401" title="401 Unauthorized">Section 3.1</a> of <a href="#Part7" id="rfc.xref.Part7.4"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
    1047                </tr>
    1048                <tr>
    1049                   <td class="left">402</td>
    1050                   <td class="left">Payment Required</td>
    1051                   <td class="left"><a href="#status.402" id="rfc.xref.status.402.1" title="402 Payment Required">Section&nbsp;8.4.3</a></td>
    1052                </tr>
    1053                <tr>
    1054                   <td class="left">403</td>
    1055                   <td class="left">Forbidden</td>
    1056                   <td class="left"><a href="#status.403" id="rfc.xref.status.403.1" title="403 Forbidden">Section&nbsp;8.4.4</a></td>
    1057                </tr>
    1058                <tr>
    1059                   <td class="left">404</td>
    1060                   <td class="left">Not Found</td>
    1061                   <td class="left"><a href="#status.404" id="rfc.xref.status.404.1" title="404 Not Found">Section&nbsp;8.4.5</a></td>
    1062                </tr>
    1063                <tr>
    1064                   <td class="left">405</td>
    1065                   <td class="left">Method Not Allowed</td>
    1066                   <td class="left"><a href="#status.405" id="rfc.xref.status.405.1" title="405 Method Not Allowed">Section&nbsp;8.4.6</a></td>
    1067                </tr>
    1068                <tr>
    1069                   <td class="left">406</td>
    1070                   <td class="left">Not Acceptable</td>
    1071                   <td class="left"><a href="#status.406" id="rfc.xref.status.406.1" title="406 Not Acceptable">Section&nbsp;8.4.7</a></td>
    1072                </tr>
    1073                <tr>
    1074                   <td class="left">407</td>
    1075                   <td class="left">Proxy Authentication Required</td>
    1076                   <td class="left"><a href="p7-auth.html#status.407" title="407 Proxy Authentication Required">Section 3.2</a> of <a href="#Part7" id="rfc.xref.Part7.5"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
    1077                </tr>
    1078                <tr>
    1079                   <td class="left">408</td>
    1080                   <td class="left">Request Time-out</td>
    1081                   <td class="left"><a href="#status.408" id="rfc.xref.status.408.1" title="408 Request Timeout">Section&nbsp;8.4.9</a></td>
    1082                </tr>
    1083                <tr>
    1084                   <td class="left">409</td>
    1085                   <td class="left">Conflict</td>
    1086                   <td class="left"><a href="#status.409" id="rfc.xref.status.409.1" title="409 Conflict">Section&nbsp;8.4.10</a></td>
    1087                </tr>
    1088                <tr>
    1089                   <td class="left">410</td>
    1090                   <td class="left">Gone</td>
    1091                   <td class="left"><a href="#status.410" id="rfc.xref.status.410.1" title="410 Gone">Section&nbsp;8.4.11</a></td>
    1092                </tr>
    1093                <tr>
    1094                   <td class="left">411</td>
    1095                   <td class="left">Length Required</td>
    1096                   <td class="left"><a href="#status.411" id="rfc.xref.status.411.1" title="411 Length Required">Section&nbsp;8.4.12</a></td>
    1097                </tr>
    1098                <tr>
    1099                   <td class="left">412</td>
    1100                   <td class="left">Precondition Failed</td>
    1101                   <td class="left"><a href="p4-conditional.html#status.412" title="412 Precondition Failed">Section 4.2</a> of <a href="#Part4" id="rfc.xref.Part4.7"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
    1102                </tr>
    1103                <tr>
    1104                   <td class="left">413</td>
    1105                   <td class="left">Request Representation Too Large</td>
    1106                   <td class="left"><a href="#status.413" id="rfc.xref.status.413.1" title="413 Request Representation Too Large">Section&nbsp;8.4.14</a></td>
    1107                </tr>
    1108                <tr>
    1109                   <td class="left">414</td>
    1110                   <td class="left">URI Too Long</td>
    1111                   <td class="left"><a href="#status.414" id="rfc.xref.status.414.1" title="414 URI Too Long">Section&nbsp;8.4.15</a></td>
    1112                </tr>
    1113                <tr>
    1114                   <td class="left">415</td>
    1115                   <td class="left">Unsupported Media Type</td>
    1116                   <td class="left"><a href="#status.415" id="rfc.xref.status.415.1" title="415 Unsupported Media Type">Section&nbsp;8.4.16</a></td>
    1117                </tr>
    1118                <tr>
    1119                   <td class="left">416</td>
    1120                   <td class="left">Requested range not satisfiable</td>
    1121                   <td class="left"><a href="p5-range.html#status.416" title="416 Requested Range Not Satisfiable">Section 3.2</a> of <a href="#Part5" id="rfc.xref.Part5.5"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
    1122                </tr>
    1123                <tr>
    1124                   <td class="left">417</td>
    1125                   <td class="left">Expectation Failed</td>
    1126                   <td class="left"><a href="#status.417" id="rfc.xref.status.417.1" title="417 Expectation Failed">Section&nbsp;8.4.18</a></td>
    1127                </tr>
    1128                <tr>
    1129                   <td class="left">426</td>
    1130                   <td class="left">Upgrade Required</td>
    1131                   <td class="left"><a href="#status.426" id="rfc.xref.status.426.1" title="426 Upgrade Required">Section&nbsp;8.4.19</a></td>
    1132                </tr>
    1133                <tr>
    1134                   <td class="left">500</td>
    1135                   <td class="left">Internal Server Error</td>
    1136                   <td class="left"><a href="#status.500" id="rfc.xref.status.500.1" title="500 Internal Server Error">Section&nbsp;8.5.1</a></td>
    1137                </tr>
    1138                <tr>
    1139                   <td class="left">501</td>
    1140                   <td class="left">Not Implemented</td>
    1141                   <td class="left"><a href="#status.501" id="rfc.xref.status.501.1" title="501 Not Implemented">Section&nbsp;8.5.2</a></td>
    1142                </tr>
    1143                <tr>
    1144                   <td class="left">502</td>
    1145                   <td class="left">Bad Gateway</td>
    1146                   <td class="left"><a href="#status.502" id="rfc.xref.status.502.1" title="502 Bad Gateway">Section&nbsp;8.5.3</a></td>
    1147                </tr>
    1148                <tr>
    1149                   <td class="left">503</td>
    1150                   <td class="left">Service Unavailable</td>
    1151                   <td class="left"><a href="#status.503" id="rfc.xref.status.503.1" title="503 Service Unavailable">Section&nbsp;8.5.4</a></td>
    1152                </tr>
    1153                <tr>
    1154                   <td class="left">504</td>
    1155                   <td class="left">Gateway Time-out</td>
    1156                   <td class="left"><a href="#status.504" id="rfc.xref.status.504.1" title="504 Gateway Timeout">Section&nbsp;8.5.5</a></td>
    1157                </tr>
    1158                <tr>
    1159                   <td class="left">505</td>
    1160                   <td class="left">HTTP Version not supported</td>
    1161                   <td class="left"><a href="#status.505" id="rfc.xref.status.505.1" title="505 HTTP Version Not Supported">Section&nbsp;8.5.6</a></td>
    1162                </tr>
    1163             </tbody>
    1164          </table>
     967            though such understanding is obviously desirable. However, applications <em class="bcp14">MUST</em> understand the class of any status code, as indicated by the first digit, and treat any unrecognized response as being equivalent
     968            to the x00 status code of that class, with the exception that an unrecognized response <em class="bcp14">MUST NOT</em> be cached. For example, if an unrecognized status code of 431 is received by the client, it can safely assume that there was
     969            something wrong with its request and treat the response as if it had received a 400 status code. In such cases, user agents <em class="bcp14">SHOULD</em> present to the user the representation enclosed with the response, since that representation is likely to include human-readable
     970            information which will explain the unusual status.
     971         </p>
     972         <div id="overview.of.status.codes">
     973            <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a>&nbsp;<a href="#overview.of.status.codes">Overview of Status Codes</a></h2>
     974            <p id="rfc.section.4.1.p.1">The status codes listed below are defined in <a href="#status.codes" title="Status Code Definitions">Section&nbsp;8</a> of this specification, <a href="p4-conditional.html#status.code.definitions" title="Status Code Definitions">Section 4</a> of <a href="#Part4" id="rfc.xref.Part4.5"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>, <a href="p5-range.html#status.code.definitions" title="Status Code Definitions">Section 3</a> of <a href="#Part5" id="rfc.xref.Part5.3"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>, and <a href="p7-auth.html#status.code.definitions" title="Status Code Definitions">Section 3</a> of <a href="#Part7" id="rfc.xref.Part7.3"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a>. The reason phrases listed here are only recommendations — they can be replaced by local equivalents without affecting the
     975               protocol.
     976            </p>
     977            <div id="rfc.table.u.3">
     978               <table class="tt full left" cellpadding="3" cellspacing="0">
     979                  <thead>
     980                     <tr>
     981                        <th>Status-Code</th>
     982                        <th>Reason-Phrase</th>
     983                        <th>Defined in...</th>
     984                     </tr>
     985                  </thead>
     986                  <tbody>
     987                     <tr>
     988                        <td class="left">100</td>
     989                        <td class="left">Continue</td>
     990                        <td class="left"><a href="#status.100" id="rfc.xref.status.100.1" title="100 Continue">Section&nbsp;8.1.1</a></td>
     991                     </tr>
     992                     <tr>
     993                        <td class="left">101</td>
     994                        <td class="left">Switching Protocols</td>
     995                        <td class="left"><a href="#status.101" id="rfc.xref.status.101.1" title="101 Switching Protocols">Section&nbsp;8.1.2</a></td>
     996                     </tr>
     997                     <tr>
     998                        <td class="left">200</td>
     999                        <td class="left">OK</td>
     1000                        <td class="left"><a href="#status.200" id="rfc.xref.status.200.1" title="200 OK">Section&nbsp;8.2.1</a></td>
     1001                     </tr>
     1002                     <tr>
     1003                        <td class="left">201</td>
     1004                        <td class="left">Created</td>
     1005                        <td class="left"><a href="#status.201" id="rfc.xref.status.201.1" title="201 Created">Section&nbsp;8.2.2</a></td>
     1006                     </tr>
     1007                     <tr>
     1008                        <td class="left">202</td>
     1009                        <td class="left">Accepted</td>
     1010                        <td class="left"><a href="#status.202" id="rfc.xref.status.202.1" title="202 Accepted">Section&nbsp;8.2.3</a></td>
     1011                     </tr>
     1012                     <tr>
     1013                        <td class="left">203</td>
     1014                        <td class="left">Non-Authoritative Information</td>
     1015                        <td class="left"><a href="#status.203" id="rfc.xref.status.203.1" title="203 Non-Authoritative Information">Section&nbsp;8.2.4</a></td>
     1016                     </tr>
     1017                     <tr>
     1018                        <td class="left">204</td>
     1019                        <td class="left">No Content</td>
     1020                        <td class="left"><a href="#status.204" id="rfc.xref.status.204.1" title="204 No Content">Section&nbsp;8.2.5</a></td>
     1021                     </tr>
     1022                     <tr>
     1023                        <td class="left">205</td>
     1024                        <td class="left">Reset Content</td>
     1025                        <td class="left"><a href="#status.205" id="rfc.xref.status.205.1" title="205 Reset Content">Section&nbsp;8.2.6</a></td>
     1026                     </tr>
     1027                     <tr>
     1028                        <td class="left">206</td>
     1029                        <td class="left">Partial Content</td>
     1030                        <td class="left"><a href="p5-range.html#status.206" title="206 Partial Content">Section 3.1</a> of <a href="#Part5" id="rfc.xref.Part5.4"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
     1031                     </tr>
     1032                     <tr>
     1033                        <td class="left">300</td>
     1034                        <td class="left">Multiple Choices</td>
     1035                        <td class="left"><a href="#status.300" id="rfc.xref.status.300.1" title="300 Multiple Choices">Section&nbsp;8.3.1</a></td>
     1036                     </tr>
     1037                     <tr>
     1038                        <td class="left">301</td>
     1039                        <td class="left">Moved Permanently</td>
     1040                        <td class="left"><a href="#status.301" id="rfc.xref.status.301.1" title="301 Moved Permanently">Section&nbsp;8.3.2</a></td>
     1041                     </tr>
     1042                     <tr>
     1043                        <td class="left">302</td>
     1044                        <td class="left">Found</td>
     1045                        <td class="left"><a href="#status.302" id="rfc.xref.status.302.1" title="302 Found">Section&nbsp;8.3.3</a></td>
     1046                     </tr>
     1047                     <tr>
     1048                        <td class="left">303</td>
     1049                        <td class="left">See Other</td>
     1050                        <td class="left"><a href="#status.303" id="rfc.xref.status.303.1" title="303 See Other">Section&nbsp;8.3.4</a></td>
     1051                     </tr>
     1052                     <tr>
     1053                        <td class="left">304</td>
     1054                        <td class="left">Not Modified</td>
     1055                        <td class="left"><a href="p4-conditional.html#status.304" title="304 Not Modified">Section 4.1</a> of <a href="#Part4" id="rfc.xref.Part4.6"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
     1056                     </tr>
     1057                     <tr>
     1058                        <td class="left">305</td>
     1059                        <td class="left">Use Proxy</td>
     1060                        <td class="left"><a href="#status.305" id="rfc.xref.status.305.1" title="305 Use Proxy">Section&nbsp;8.3.6</a></td>
     1061                     </tr>
     1062                     <tr>
     1063                        <td class="left">307</td>
     1064                        <td class="left">Temporary Redirect</td>
     1065                        <td class="left"><a href="#status.307" id="rfc.xref.status.307.1" title="307 Temporary Redirect">Section&nbsp;8.3.8</a></td>
     1066                     </tr>
     1067                     <tr>
     1068                        <td class="left">400</td>
     1069                        <td class="left">Bad Request</td>
     1070                        <td class="left"><a href="#status.400" id="rfc.xref.status.400.1" title="400 Bad Request">Section&nbsp;8.4.1</a></td>
     1071                     </tr>
     1072                     <tr>
     1073                        <td class="left">401</td>
     1074                        <td class="left">Unauthorized</td>
     1075                        <td class="left"><a href="p7-auth.html#status.401" title="401 Unauthorized">Section 3.1</a> of <a href="#Part7" id="rfc.xref.Part7.4"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
     1076                     </tr>
     1077                     <tr>
     1078                        <td class="left">402</td>
     1079                        <td class="left">Payment Required</td>
     1080                        <td class="left"><a href="#status.402" id="rfc.xref.status.402.1" title="402 Payment Required">Section&nbsp;8.4.3</a></td>
     1081                     </tr>
     1082                     <tr>
     1083                        <td class="left">403</td>
     1084                        <td class="left">Forbidden</td>
     1085                        <td class="left"><a href="#status.403" id="rfc.xref.status.403.1" title="403 Forbidden">Section&nbsp;8.4.4</a></td>
     1086                     </tr>
     1087                     <tr>
     1088                        <td class="left">404</td>
     1089                        <td class="left">Not Found</td>
     1090                        <td class="left"><a href="#status.404" id="rfc.xref.status.404.1" title="404 Not Found">Section&nbsp;8.4.5</a></td>
     1091                     </tr>
     1092                     <tr>
     1093                        <td class="left">405</td>
     1094                        <td class="left">Method Not Allowed</td>
     1095                        <td class="left"><a href="#status.405" id="rfc.xref.status.405.1" title="405 Method Not Allowed">Section&nbsp;8.4.6</a></td>
     1096                     </tr>
     1097                     <tr>
     1098                        <td class="left">406</td>
     1099                        <td class="left">Not Acceptable</td>
     1100                        <td class="left"><a href="#status.406" id="rfc.xref.status.406.1" title="406 Not Acceptable">Section&nbsp;8.4.7</a></td>
     1101                     </tr>
     1102                     <tr>
     1103                        <td class="left">407</td>
     1104                        <td class="left">Proxy Authentication Required</td>
     1105                        <td class="left"><a href="p7-auth.html#status.407" title="407 Proxy Authentication Required">Section 3.2</a> of <a href="#Part7" id="rfc.xref.Part7.5"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
     1106                     </tr>
     1107                     <tr>
     1108                        <td class="left">408</td>
     1109                        <td class="left">Request Time-out</td>
     1110                        <td class="left"><a href="#status.408" id="rfc.xref.status.408.1" title="408 Request Timeout">Section&nbsp;8.4.9</a></td>
     1111                     </tr>
     1112                     <tr>
     1113                        <td class="left">409</td>
     1114                        <td class="left">Conflict</td>
     1115                        <td class="left"><a href="#status.409" id="rfc.xref.status.409.1" title="409 Conflict">Section&nbsp;8.4.10</a></td>
     1116                     </tr>
     1117                     <tr>
     1118                        <td class="left">410</td>
     1119                        <td class="left">Gone</td>
     1120                        <td class="left"><a href="#status.410" id="rfc.xref.status.410.1" title="410 Gone">Section&nbsp;8.4.11</a></td>
     1121                     </tr>
     1122                     <tr>
     1123                        <td class="left">411</td>
     1124                        <td class="left">Length Required</td>
     1125                        <td class="left"><a href="#status.411" id="rfc.xref.status.411.1" title="411 Length Required">Section&nbsp;8.4.12</a></td>
     1126                     </tr>
     1127                     <tr>
     1128                        <td class="left">412</td>
     1129                        <td class="left">Precondition Failed</td>
     1130                        <td class="left"><a href="p4-conditional.html#status.412" title="412 Precondition Failed">Section 4.2</a> of <a href="#Part4" id="rfc.xref.Part4.7"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
     1131                     </tr>
     1132                     <tr>
     1133                        <td class="left">413</td>
     1134                        <td class="left">Request Representation Too Large</td>
     1135                        <td class="left"><a href="#status.413" id="rfc.xref.status.413.1" title="413 Request Representation Too Large">Section&nbsp;8.4.14</a></td>
     1136                     </tr>
     1137                     <tr>
     1138                        <td class="left">414</td>
     1139                        <td class="left">URI Too Long</td>
     1140                        <td class="left"><a href="#status.414" id="rfc.xref.status.414.1" title="414 URI Too Long">Section&nbsp;8.4.15</a></td>
     1141                     </tr>
     1142                     <tr>
     1143                        <td class="left">415</td>
     1144                        <td class="left">Unsupported Media Type</td>
     1145                        <td class="left"><a href="#status.415" id="rfc.xref.status.415.1" title="415 Unsupported Media Type">Section&nbsp;8.4.16</a></td>
     1146                     </tr>
     1147                     <tr>
     1148                        <td class="left">416</td>
     1149                        <td class="left">Requested range not satisfiable</td>
     1150                        <td class="left"><a href="p5-range.html#status.416" title="416 Requested Range Not Satisfiable">Section 3.2</a> of <a href="#Part5" id="rfc.xref.Part5.5"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
     1151                     </tr>
     1152                     <tr>
     1153                        <td class="left">417</td>
     1154                        <td class="left">Expectation Failed</td>
     1155                        <td class="left"><a href="#status.417" id="rfc.xref.status.417.1" title="417 Expectation Failed">Section&nbsp;8.4.18</a></td>
     1156                     </tr>
     1157                     <tr>
     1158                        <td class="left">426</td>
     1159                        <td class="left">Upgrade Required</td>
     1160                        <td class="left"><a href="#status.426" id="rfc.xref.status.426.1" title="426 Upgrade Required">Section&nbsp;8.4.19</a></td>
     1161                     </tr>
     1162                     <tr>
     1163                        <td class="left">500</td>
     1164                        <td class="left">Internal Server Error</td>
     1165                        <td class="left"><a href="#status.500" id="rfc.xref.status.500.1" title="500 Internal Server Error">Section&nbsp;8.5.1</a></td>
     1166                     </tr>
     1167                     <tr>
     1168                        <td class="left">501</td>
     1169                        <td class="left">Not Implemented</td>
     1170                        <td class="left"><a href="#status.501" id="rfc.xref.status.501.1" title="501 Not Implemented">Section&nbsp;8.5.2</a></td>
     1171                     </tr>
     1172                     <tr>
     1173                        <td class="left">502</td>
     1174                        <td class="left">Bad Gateway</td>
     1175                        <td class="left"><a href="#status.502" id="rfc.xref.status.502.1" title="502 Bad Gateway">Section&nbsp;8.5.3</a></td>
     1176                     </tr>
     1177                     <tr>
     1178                        <td class="left">503</td>
     1179                        <td class="left">Service Unavailable</td>
     1180                        <td class="left"><a href="#status.503" id="rfc.xref.status.503.1" title="503 Service Unavailable">Section&nbsp;8.5.4</a></td>
     1181                     </tr>
     1182                     <tr>
     1183                        <td class="left">504</td>
     1184                        <td class="left">Gateway Time-out</td>
     1185                        <td class="left"><a href="#status.504" id="rfc.xref.status.504.1" title="504 Gateway Timeout">Section&nbsp;8.5.5</a></td>
     1186                     </tr>
     1187                     <tr>
     1188                        <td class="left">505</td>
     1189                        <td class="left">HTTP Version not supported</td>
     1190                        <td class="left"><a href="#status.505" id="rfc.xref.status.505.1" title="505 HTTP Version Not Supported">Section&nbsp;8.5.6</a></td>
     1191                     </tr>
     1192                  </tbody>
     1193               </table>
     1194            </div>
     1195            <p id="rfc.section.4.1.p.2">Note that this list is not exhaustive — it does not include extension status codes defined in other specifications.</p>
     1196         </div>
     1197         <div id="status.code.registry">
     1198            <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a>&nbsp;<a href="#status.code.registry">Status Code Registry</a></h2>
     1199            <p id="rfc.section.4.2.p.1">The HTTP Status Code Registry defines the name space for the Status-Code token in the Status-Line of an HTTP response.</p>
     1200            <p id="rfc.section.4.2.p.2">Values to be added to this name space are subject to IETF review (<a href="#RFC5226" id="rfc.xref.RFC5226.2"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="https://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
     1201            </p>
     1202            <p id="rfc.section.4.2.p.3">The registry itself is maintained at &lt;<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>&gt;.
     1203            </p>
     1204            <div id="considerations.for.new.status.codes">
     1205               <h3 id="rfc.section.4.2.1"><a href="#rfc.section.4.2.1">4.2.1</a>&nbsp;<a href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></h3>
     1206               <p id="rfc.section.4.2.1.p.1">When it is necessary to express new semantics for a HTTP response that aren't specific to a single application or media type,
     1207                  and currently defined status codes are inadequate, a new status code can be registered.
     1208               </p>
     1209               <p id="rfc.section.4.2.1.p.2">HTTP status codes are generic; that is, they are potentially applicable to any resource, not just one particular media type,
     1210                  "type" of resource, or application. As such, it is preferred that new HTTP status codes be registered in a document that isn't
     1211                  specific to a single application, so that this is clear.
     1212               </p>
     1213               <p id="rfc.section.4.2.1.p.3">Definitions of new HTTP status codes typically explain the request conditions that produce a response containing the status
     1214                  code (e.g., combinations of request headers and/or method(s)), along with any interactions with response headers (e.g., those
     1215                  that are required, those that modify the semantics of the response).
     1216               </p>
     1217               <p id="rfc.section.4.2.1.p.4">New HTTP status codes are required to fall under one of the categories defined in <a href="#status.codes" title="Status Code Definitions">Section&nbsp;8</a>. To allow existing parsers to properly handle them, new status codes cannot disallow a response body, although they can mandate
     1218                  a zero-length response body. They can require the presence of one or more particular HTTP response header(s).
     1219               </p>
     1220               <p id="rfc.section.4.2.1.p.5">Likewise, their definitions can specify that caches are allowed to use heuristics to determine their freshness (see <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>; by default, it is not allowed), and can define how to determine the resource which they carry a representation for (see <a href="#identifying.response.associated.with.representation" title="Identifying the Resource Associated with a Representation">Section&nbsp;6.1</a>; by default, it is anonymous).
     1221               </p>
     1222            </div>
     1223         </div>
    11651224      </div>
    1166       <p id="rfc.section.4.1.p.2">Note that this list is not exhaustive — it does not include extension status codes defined in other specifications.</p>
    1167       <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a>&nbsp;<a id="status.code.registry" href="#status.code.registry">Status Code Registry</a></h2>
    1168       <p id="rfc.section.4.2.p.1">The HTTP Status Code Registry defines the name space for the Status-Code token in the Status-Line of an HTTP response.</p>
    1169       <p id="rfc.section.4.2.p.2">Values to be added to this name space are subject to IETF review (<a href="#RFC5226" id="rfc.xref.RFC5226.2"><cite title="Guidelines for Writing an IANA Considerations Section in RFCs">[RFC5226]</cite></a>, <a href="http://tools.ietf.org/html/rfc5226#section-4.1">Section 4.1</a>).
    1170       </p>
    1171       <p id="rfc.section.4.2.p.3">The registry itself is maintained at &lt;<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>&gt;.
    1172       </p>
    1173       <h3 id="rfc.section.4.2.1"><a href="#rfc.section.4.2.1">4.2.1</a>&nbsp;<a id="considerations.for.new.status.codes" href="#considerations.for.new.status.codes">Considerations for New Status Codes</a></h3>
    1174       <p id="rfc.section.4.2.1.p.1">When it is necessary to express new semantics for a HTTP response that aren't specific to a single application or media type,
    1175          and currently defined status codes are inadequate, a new status code can be registered.
    1176       </p>
    1177       <p id="rfc.section.4.2.1.p.2">HTTP status codes are generic; that is, they are potentially applicable to any resource, not just one particular media type,
    1178          "type" of resource, or application. As such, it is preferred that new HTTP status codes be registered in a document that isn't
    1179          specific to a single application, so that this is clear.
    1180       </p>
    1181       <p id="rfc.section.4.2.1.p.3">Definitions of new HTTP status codes typically explain the request conditions that produce a response containing the status
    1182          code (e.g., combinations of request headers and/or method(s)), along with any interactions with response headers (e.g., those
    1183          that are required, those that modify the semantics of the response).
    1184       </p>
    1185       <p id="rfc.section.4.2.1.p.4">New HTTP status codes are required to fall under one of the categories defined in <a href="#status.codes" title="Status Code Definitions">Section&nbsp;8</a>. To allow existing parsers to properly handle them, new status codes cannot disallow a response body, although they can mandate
    1186          a zero-length response body. They can require the presence of one or more particular HTTP response header(s).
    1187       </p>
    1188       <p id="rfc.section.4.2.1.p.5">Likewise, their definitions can specify that caches are allowed to use heuristics to determine their freshness (see <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>; by default, it is not allowed), and can define how to determine the resource which they carry a representation for (see <a href="#identifying.response.associated.with.representation" title="Identifying the Resource Associated with a Representation">Section&nbsp;6.1</a>; by default, it is anonymous).
    1189       </p>
    1190       <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a id="response.header.fields" href="#response.header.fields">Response Header Fields</a></h1>
    1191       <p id="rfc.section.5.p.1">The response header fields allow the server to pass additional information about the response which cannot be placed in the
    1192          Status-Line. These header fields give information about the server and about further access to the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.19"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>).
    1193       </p>
    1194       <div id="rfc.table.u.4">
    1195          <table class="tt full left" cellpadding="3" cellspacing="0">
    1196             <thead>
    1197                <tr>
    1198                   <th>Header Field Name</th>
    1199                   <th>Defined in...</th>
    1200                </tr>
    1201             </thead>
    1202             <tbody>
    1203                <tr>
    1204                   <td class="left">Accept-Ranges</td>
    1205                   <td class="left"><a href="p5-range.html#header.accept-ranges" title="Accept-Ranges">Section 5.1</a> of <a href="#Part5" id="rfc.xref.Part5.6"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
    1206                </tr>
    1207                <tr>
    1208                   <td class="left">Age</td>
    1209                   <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 3.1</a> of <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
    1210                </tr>
    1211                <tr>
    1212                   <td class="left">Allow</td>
    1213                   <td class="left"><a href="#header.allow" id="rfc.xref.header.allow.2" title="Allow">Section&nbsp;9.1</a></td>
    1214                </tr>
    1215                <tr>
    1216                   <td class="left">ETag</td>
    1217                   <td class="left"><a href="p4-conditional.html#header.etag" title="ETag">Section 2.2</a> of <a href="#Part4" id="rfc.xref.Part4.8"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
    1218                </tr>
    1219                <tr>
    1220                   <td class="left">Location</td>
    1221                   <td class="left"><a href="#header.location" id="rfc.xref.header.location.1" title="Location">Section&nbsp;9.4</a></td>
    1222                </tr>
    1223                <tr>
    1224                   <td class="left">Proxy-Authenticate</td>
    1225                   <td class="left"><a href="p7-auth.html#header.proxy-authenticate" title="Proxy-Authenticate">Section 4.2</a> of <a href="#Part7" id="rfc.xref.Part7.6"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
    1226                </tr>
    1227                <tr>
    1228                   <td class="left">Retry-After</td>
    1229                   <td class="left"><a href="#header.retry-after" id="rfc.xref.header.retry-after.1" title="Retry-After">Section&nbsp;9.7</a></td>
    1230                </tr>
    1231                <tr>
    1232                   <td class="left">Server</td>
    1233                   <td class="left"><a href="#header.server" id="rfc.xref.header.server.1" title="Server">Section&nbsp;9.8</a></td>
    1234                </tr>
    1235                <tr>
    1236                   <td class="left">Vary</td>
    1237                   <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 3.5</a> of <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
    1238                </tr>
    1239                <tr>
    1240                   <td class="left">WWW-Authenticate</td>
    1241                   <td class="left"><a href="p7-auth.html#header.www-authenticate" title="WWW-Authenticate">Section 4.4</a> of <a href="#Part7" id="rfc.xref.Part7.7"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
    1242                </tr>
    1243             </tbody>
    1244          </table>
     1225      <div id="response.header.fields">
     1226         <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a>&nbsp;<a href="#response.header.fields">Response Header Fields</a></h1>
     1227         <p id="rfc.section.5.p.1">The response header fields allow the server to pass additional information about the response which cannot be placed in the
     1228            Status-Line. These header fields give information about the server and about further access to the target resource (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.19"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>).
     1229         </p>
     1230         <div id="rfc.table.u.4">
     1231            <table class="tt full left" cellpadding="3" cellspacing="0">
     1232               <thead>
     1233                  <tr>
     1234                     <th>Header Field Name</th>
     1235                     <th>Defined in...</th>
     1236                  </tr>
     1237               </thead>
     1238               <tbody>
     1239                  <tr>
     1240                     <td class="left">Accept-Ranges</td>
     1241                     <td class="left"><a href="p5-range.html#header.accept-ranges" title="Accept-Ranges">Section 5.1</a> of <a href="#Part5" id="rfc.xref.Part5.6"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a></td>
     1242                  </tr>
     1243                  <tr>
     1244                     <td class="left">Age</td>
     1245                     <td class="left"><a href="p6-cache.html#header.age" title="Age">Section 3.1</a> of <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
     1246                  </tr>
     1247                  <tr>
     1248                     <td class="left">Allow</td>
     1249                     <td class="left"><a href="#header.allow" id="rfc.xref.header.allow.2" title="Allow">Section&nbsp;9.1</a></td>
     1250                  </tr>
     1251                  <tr>
     1252                     <td class="left">ETag</td>
     1253                     <td class="left"><a href="p4-conditional.html#header.etag" title="ETag">Section 2.2</a> of <a href="#Part4" id="rfc.xref.Part4.8"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a></td>
     1254                  </tr>
     1255                  <tr>
     1256                     <td class="left">Location</td>
     1257                     <td class="left"><a href="#header.location" id="rfc.xref.header.location.1" title="Location">Section&nbsp;9.4</a></td>
     1258                  </tr>
     1259                  <tr>
     1260                     <td class="left">Proxy-Authenticate</td>
     1261                     <td class="left"><a href="p7-auth.html#header.proxy-authenticate" title="Proxy-Authenticate">Section 4.2</a> of <a href="#Part7" id="rfc.xref.Part7.6"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
     1262                  </tr>
     1263                  <tr>
     1264                     <td class="left">Retry-After</td>
     1265                     <td class="left"><a href="#header.retry-after" id="rfc.xref.header.retry-after.1" title="Retry-After">Section&nbsp;9.7</a></td>
     1266                  </tr>
     1267                  <tr>
     1268                     <td class="left">Server</td>
     1269                     <td class="left"><a href="#header.server" id="rfc.xref.header.server.1" title="Server">Section&nbsp;9.8</a></td>
     1270                  </tr>
     1271                  <tr>
     1272                     <td class="left">Vary</td>
     1273                     <td class="left"><a href="p6-cache.html#header.vary" title="Vary">Section 3.5</a> of <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a></td>
     1274                  </tr>
     1275                  <tr>
     1276                     <td class="left">WWW-Authenticate</td>
     1277                     <td class="left"><a href="p7-auth.html#header.www-authenticate" title="WWW-Authenticate">Section 4.4</a> of <a href="#Part7" id="rfc.xref.Part7.7"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a></td>
     1278                  </tr>
     1279               </tbody>
     1280            </table>
     1281         </div>
    12451282      </div>
    1246       <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a id="representation" href="#representation">Representation</a></h1>
    1247       <p id="rfc.section.6.p.1">Request and Response messages <em class="bcp14">MAY</em> transfer a representation if not otherwise restricted by the request method or response status code. A representation consists
    1248          of metadata (representation header fields) and data (representation body). When a complete or partial representation is enclosed
    1249          in an HTTP message, it is referred to as the payload of the message. HTTP representations are defined in <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.
    1250       </p>
    1251       <p id="rfc.section.6.p.2">A representation body is only present in a message when a message-body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.20"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. The representation body is obtained from the message-body by decoding any Transfer-Encoding that might have been applied
    1252          to ensure safe and proper transfer of the message.
    1253       </p>
    1254       <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a id="identifying.response.associated.with.representation" href="#identifying.response.associated.with.representation">Identifying the Resource Associated with a Representation</a></h2>
    1255       <p id="rfc.section.6.1.p.1">It is sometimes necessary to determine an identifier for the resource associated with a representation.</p>
    1256       <p id="rfc.section.6.1.p.2">An HTTP request representation, when present, is always associated with an anonymous (i.e., unidentified) resource.</p>
    1257       <p id="rfc.section.6.1.p.3">In the common case, an HTTP response is a representation of the target resource (see <a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.21"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). However, this is not always the case. To determine the URI of the resource a response is associated with, the following
    1258          rules are used (with the first applicable one being selected):
    1259       </p>
    1260       <ol>
    1261          <li>If the response status code is 200 or 203 and the request method was GET, the response payload is a representation of the
    1262             target resource.
    1263          </li>
    1264          <li>If the response status code is 204, 206, or 304 and the request method was GET or HEAD, the response payload is a partial
    1265             representation of the target resource (see <a href="p6-cache.html#combining.responses" title="Combining Responses">Section 2.8</a> of <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    1266          </li>
    1267          <li>If the response has a Content-Location header field, and that URI is the same as the effective request URI, the response payload
    1268             is a representation of the target resource.
    1269          </li>
    1270          <li>If the response has a Content-Location header field, and that URI is not the same as the effective request URI, then the response
    1271             asserts that its payload is a representation of the resource identified by the Content-Location URI. However, such an assertion
    1272             cannot be trusted unless it can be verified by other means (not defined by HTTP).
    1273          </li>
    1274          <li>Otherwise, the response is a representation of an anonymous (i.e., unidentified) resource.</li>
    1275       </ol>
    1276       <p id="rfc.section.6.1.p.5"> <span class="comment" id="TODO-req-uri">[<a href="#TODO-req-uri" class="smpl">TODO-req-uri</a>: The comparison function is going to have to be defined somewhere, because we already need to compare URIs for things like
    1277             cache invalidation.]</span>
    1278       </p>
    1279       <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a id="method.definitions" href="#method.definitions">Method Definitions</a></h1>
    1280       <p id="rfc.section.7.p.1">The set of common request methods for HTTP/1.1 is defined below. Although this set can be expanded, additional methods cannot
    1281          be assumed to share the same semantics for separately extended clients and servers.
    1282       </p>
    1283       <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a id="safe.and.idempotent" href="#safe.and.idempotent">Safe and Idempotent Methods</a></h2>
    1284       <div id="rfc.iref.s.1"></div>
    1285       <h3 id="rfc.section.7.1.1"><a href="#rfc.section.7.1.1">7.1.1</a>&nbsp;<a id="safe.methods" href="#safe.methods">Safe Methods</a></h3>
    1286       <p id="rfc.section.7.1.1.p.1">Implementors need to be aware that the software represents the user in their interactions over the Internet, and need to allow
    1287          the user to be aware of any actions they take which might have an unexpected significance to themselves or others.
    1288       </p>
    1289       <p id="rfc.section.7.1.1.p.2">In particular, the convention has been established that the GET, HEAD, OPTIONS, and TRACE request methods <em class="bcp14">SHOULD NOT</em> have the significance of taking an action other than retrieval. These request methods ought to be considered "<dfn id="safe">safe</dfn>". This allows user agents to represent other methods, such as POST, PUT and DELETE, in a special way, so that the user is
    1290          made aware of the fact that a possibly unsafe action is being requested.
    1291       </p>
    1292       <p id="rfc.section.7.1.1.p.3">Naturally, it is not possible to ensure that the server does not generate side-effects as a result of performing a GET request;
    1293          in fact, some dynamic resources consider that a feature. The important distinction here is that the user did not request the
    1294          side-effects, so therefore cannot be held accountable for them.
    1295       </p>
    1296       <div id="rfc.iref.i.1"></div>
    1297       <h3 id="rfc.section.7.1.2"><a href="#rfc.section.7.1.2">7.1.2</a>&nbsp;<a id="idempotent.methods" href="#idempotent.methods">Idempotent Methods</a></h3>
    1298       <p id="rfc.section.7.1.2.p.1">Request methods can also have the property of "idempotence" in that, aside from error or expiration issues, the intended effect
    1299          of multiple identical requests is the same as for a single request. PUT, DELETE, and all safe request methods are idempotent.
    1300          It is important to note that idempotence refers only to changes requested by the client: a server is free to change its state
    1301          due to multiple requests for the purpose of tracking those requests, versioning of results, etc.
    1302       </p>
    1303       <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a>&nbsp;<a id="OPTIONS" href="#OPTIONS">OPTIONS</a></h2>
    1304       <div id="rfc.iref.o.1"></div>
    1305       <div id="rfc.iref.m.1"></div>
    1306       <p id="rfc.section.7.2.p.1">The OPTIONS method requests information about the communication options available on the request/response chain identified
    1307          by the effective request URI. This method allows a client to determine the options and/or requirements associated with a resource,
    1308          or the capabilities of a server, without implying a resource action or initiating a resource retrieval.
    1309       </p>
    1310       <p id="rfc.section.7.2.p.2">Responses to the OPTIONS method are not cacheable.</p>
    1311       <p id="rfc.section.7.2.p.3">If the OPTIONS request includes a message-body (as indicated by the presence of Content-Length or Transfer-Encoding), then
    1312          the media type <em class="bcp14">MUST</em> be indicated by a Content-Type field. Although this specification does not define any use for such a body, future extensions
    1313          to HTTP might use the OPTIONS body to make more detailed queries on the server.
    1314       </p>
    1315       <p id="rfc.section.7.2.p.4">If the request-target is an asterisk ("*"), the OPTIONS request is intended to apply to the server in general rather than
    1316          to a specific resource. Since a server's communication options typically depend on the resource, the "*" request is only useful
    1317          as a "ping" or "no-op" type of method; it does nothing beyond allowing the client to test the capabilities of the server.
    1318          For example, this can be used to test a proxy for HTTP/1.1 compliance (or lack thereof).
    1319       </p>
    1320       <p id="rfc.section.7.2.p.5">If the request-target is not an asterisk, the OPTIONS request applies only to the options that are available when communicating
    1321          with that resource.
    1322       </p>
    1323       <p id="rfc.section.7.2.p.6">A 200 response <em class="bcp14">SHOULD</em> include any header fields that indicate optional features implemented by the server and applicable to that resource (e.g.,
    1324          Allow), possibly including extensions not defined by this specification. The response body, if any, <em class="bcp14">SHOULD</em> also include information about the communication options. The format for such a body is not defined by this specification,
    1325          but might be defined by future extensions to HTTP. Content negotiation <em class="bcp14">MAY</em> be used to select the appropriate response format. If no response body is included, the response <em class="bcp14">MUST</em> include a Content-Length field with a field-value of "0".
    1326       </p>
    1327       <p id="rfc.section.7.2.p.7">The Max-Forwards header field <em class="bcp14">MAY</em> be used to target a specific proxy in the request chain (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.2" title="Max-Forwards">Section&nbsp;9.5</a>). If no Max-Forwards field is present in the request, then the forwarded request <em class="bcp14">MUST NOT</em> include a Max-Forwards field.
    1328       </p>
    1329       <h2 id="rfc.section.7.3"><a href="#rfc.section.7.3">7.3</a>&nbsp;<a id="GET" href="#GET">GET</a></h2>
    1330       <div id="rfc.iref.g.5"></div>
    1331       <div id="rfc.iref.m.2"></div>
    1332       <p id="rfc.section.7.3.p.1">The GET method requests transfer of a current representation of the target resource.</p>
    1333       <p id="rfc.section.7.3.p.2">If the target resource is a data-producing process, it is the produced data which shall be returned as the representation
    1334          in the response and not the source text of the process, unless that text happens to be the output of the process.
    1335       </p>
    1336       <p id="rfc.section.7.3.p.3">The semantics of the GET method change to a "conditional GET" if the request message includes an If-Modified-Since, If-Unmodified-Since,
    1337          If-Match, If-None-Match, or If-Range header field. A conditional GET requests that the representation be transferred only
    1338          under the circumstances described by the conditional header field(s). The conditional GET request is intended to reduce unnecessary
    1339          network usage by allowing cached representations to be refreshed without requiring multiple requests or transferring data
    1340          already held by the client.
    1341       </p>
    1342       <p id="rfc.section.7.3.p.4">The semantics of the GET method change to a "partial GET" if the request message includes a Range header field. A partial
    1343          GET requests that only part of the representation be transferred, as described in <a href="p5-range.html#header.range" title="Range">Section 5.4</a> of <a href="#Part5" id="rfc.xref.Part5.7"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>. The partial GET request is intended to reduce unnecessary network usage by allowing partially-retrieved representations
    1344          to be completed without transferring data already held by the client.
    1345       </p>
    1346       <p id="rfc.section.7.3.p.5">Bodies on GET requests have no defined semantics. Note that sending a body on a GET request might cause some existing implementations
    1347          to reject the request.
    1348       </p>
    1349       <p id="rfc.section.7.3.p.6">The response to a GET request is cacheable and <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests (see <a href="#Part6" id="rfc.xref.Part6.6"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    1350       </p>
    1351       <p id="rfc.section.7.3.p.7">See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;11.2</a> for security considerations when used for forms.
    1352       </p>
    1353       <h2 id="rfc.section.7.4"><a href="#rfc.section.7.4">7.4</a>&nbsp;<a id="HEAD" href="#HEAD">HEAD</a></h2>
    1354       <div id="rfc.iref.h.1"></div>
    1355       <div id="rfc.iref.m.3"></div>
    1356       <p id="rfc.section.7.4.p.1">The HEAD method is identical to GET except that the server <em class="bcp14">MUST NOT</em> return a message-body in the response. The metadata contained in the HTTP header fields in response to a HEAD request <em class="bcp14">SHOULD</em> be identical to the information sent in response to a GET request. This method can be used for obtaining metadata about the
    1357          representation implied by the request without transferring the representation body. This method is often used for testing
    1358          hypertext links for validity, accessibility, and recent modification.
    1359       </p>
    1360       <p id="rfc.section.7.4.p.2">The response to a HEAD request is cacheable and <em class="bcp14">MAY</em> be used to satisfy a subsequent HEAD request; see <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>. It also <em class="bcp14">MAY</em> be used to update a previously cached representation from that resource; if the new field values indicate that the cached
    1361          representation differs from the current representation (as would be indicated by a change in Content-Length, Content-MD5,
    1362          ETag or Last-Modified), then the cache <em class="bcp14">MUST</em> treat the cache entry as stale.
    1363       </p>
    1364       <p id="rfc.section.7.4.p.3">Bodies on HEAD requests have no defined semantics. Note that sending a body on a HEAD request might cause some existing implementations
    1365          to reject the request.
    1366       </p>
    1367       <div id="rfc.iref.p.1"></div>
    1368       <div id="rfc.iref.m.4"></div>
    1369       <h2 id="rfc.section.7.5"><a href="#rfc.section.7.5">7.5</a>&nbsp;<a id="POST" href="#POST">POST</a></h2>
    1370       <p id="rfc.section.7.5.p.1">The POST method requests that the origin server accept the representation enclosed in the request as data to be processed
    1371          by the target resource. POST is designed to allow a uniform method to cover the following functions:
    1372       </p>
    1373       <ul>
    1374          <li>Annotation of existing resources;</li>
    1375          <li>Posting a message to a bulletin board, newsgroup, mailing list, or similar group of articles;</li>
    1376          <li>Providing a block of data, such as the result of submitting a form, to a data-handling process;</li>
    1377          <li>Extending a database through an append operation.</li>
    1378       </ul>
    1379       <p id="rfc.section.7.5.p.2">The actual function performed by the POST method is determined by the server and is usually dependent on the effective request
    1380          URI.
    1381       </p>
    1382       <p id="rfc.section.7.5.p.3">The action performed by the POST method might not result in a resource that can be identified by a URI. In this case, either
    1383          200 (OK) or 204 (No Content) is the appropriate response status code, depending on whether or not the response includes a
    1384          representation that describes the result.
    1385       </p>
    1386       <p id="rfc.section.7.5.p.4">If a resource has been created on the origin server, the response <em class="bcp14">SHOULD</em> be 201 (Created) and contain a representation which describes the status of the request and refers to the new resource, and
    1387          a Location header field (see <a href="#header.location" id="rfc.xref.header.location.2" title="Location">Section&nbsp;9.4</a>).
    1388       </p>
    1389       <p id="rfc.section.7.5.p.5">Responses to POST requests are only cacheable when they include explicit freshness information (see <a href="p6-cache.html#calculating.freshness.lifetime" title="Calculating Freshness Lifetime">Section 2.3.1</a> of <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). A cached POST response with a Content-Location header field (see <a href="p3-payload.html#header.content-location" title="Content-Location">Section 6.7</a> of <a href="#Part3" id="rfc.xref.Part3.6"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests.
    1390       </p>
    1391       <p id="rfc.section.7.5.p.6">Note that POST caching is not widely implemented. However, the 303 (See Other) response can be used to direct the user agent
    1392          to retrieve a cacheable resource.
    1393       </p>
    1394       <div id="rfc.iref.p.2"></div>
    1395       <div id="rfc.iref.m.5"></div>
    1396       <h2 id="rfc.section.7.6"><a href="#rfc.section.7.6">7.6</a>&nbsp;<a id="PUT" href="#PUT">PUT</a></h2>
    1397       <p id="rfc.section.7.6.p.1">The PUT method requests that the state of the target resource be created or replaced with the state defined by the representation
    1398          enclosed in the request message payload. A successful PUT of a given representation would suggest that a subsequent GET on
    1399          that same target resource will result in an equivalent representation being returned in a 200 (OK) response. However, there
    1400          is no guarantee that such a state change will be observable, since the target resource might be acted upon by other user agents
    1401          in parallel, or might be subject to dynamic processing by the origin server, before any subsequent GET is received. A successful
    1402          response only implies that the user agent's intent was achieved at the time of its processing by the origin server.
    1403       </p>
    1404       <p id="rfc.section.7.6.p.2">If the target resource does not have a current representation and the PUT successfully creates one, then the origin server <em class="bcp14">MUST</em> inform the user agent by sending a 201 (Created) response. If the target resource does have a current representation and that
    1405          representation is successfully modified in accordance with the state of the enclosed representation, then either a 200 (OK)
    1406          or 204 (No Content) response <em class="bcp14">SHOULD</em> be sent to indicate successful completion of the request.
    1407       </p>
    1408       <p id="rfc.section.7.6.p.3">Unrecognized header fields <em class="bcp14">SHOULD</em> be ignored (i.e., not saved as part of the resource state).
    1409       </p>
    1410       <p id="rfc.section.7.6.p.4">An origin server <em class="bcp14">SHOULD</em> verify that the PUT representation is consistent with any constraints which the server has for the target resource that cannot
    1411          or will not be changed by the PUT. This is particularly important when the origin server uses internal configuration information
    1412          related to the URI in order to set the values for representation metadata on GET responses. When a PUT representation is inconsistent
    1413          with the target resource, the origin server <em class="bcp14">SHOULD</em> either make them consistent, by transforming the representation or changing the resource configuration, or respond with an
    1414          appropriate error message containing sufficient information to explain why the representation is unsuitable. The 409 (Conflict)
    1415          or 415 (Unsupported Media Type) status codes are suggested, with the latter being specific to constraints on Content-Type
    1416          values.
    1417       </p>
    1418       <p id="rfc.section.7.6.p.5">For example, if the target resource is configured to always have a Content-Type of "text/html" and the representation being
    1419          PUT has a Content-Type of "image/jpeg", then the origin server <em class="bcp14">SHOULD</em> do one of: (a) reconfigure the target resource to reflect the new media type; (b) transform the PUT representation to a format
    1420          consistent with that of the resource before saving it as the new resource state; or, (c) reject the request with a 415 response
    1421          indicating that the target resource is limited to "text/html", perhaps including a link to a different resource that would
    1422          be a suitable target for the new representation.
    1423       </p>
    1424       <p id="rfc.section.7.6.p.6">HTTP does not define exactly how a PUT method affects the state of an origin server beyond what can be expressed by the intent
    1425          of the user agent request and the semantics of the origin server response. It does not define what a resource might be, in
    1426          any sense of that word, beyond the interface provided via HTTP. It does not define how resource state is "stored", nor how
    1427          such storage might change as a result of a change in resource state, nor how the origin server translates resource state into
    1428          representations. Generally speaking, all implementation details behind the resource interface are intentionally hidden by
    1429          the server.
    1430       </p>
    1431       <p id="rfc.section.7.6.p.7">The fundamental difference between the POST and PUT methods is highlighted by the different intent for the target resource.
    1432          The target resource in a POST request is intended to handle the enclosed representation as a data-accepting process, such
    1433          as for a gateway to some other protocol or a document that accepts annotations. In contrast, the target resource in a PUT
    1434          request is intended to take the enclosed representation as a new or replacement value. Hence, the intent of PUT is idempotent
    1435          and visible to intermediaries, even though the exact effect is only known by the origin server.
    1436       </p>
    1437       <p id="rfc.section.7.6.p.8">Proper interpretation of a PUT request presumes that the user agent knows what target resource is desired. A service that
    1438          is intended to select a proper URI on behalf of the client, after receiving a state-changing request, <em class="bcp14">SHOULD</em> be implemented using the POST method rather than PUT. If the origin server will not make the requested PUT state change to
    1439          the target resource and instead wishes to have it applied to a different resource, such as when the resource has been moved
    1440          to a different URI, then the origin server <em class="bcp14">MUST</em> send a 301 (Moved Permanently) response; the user agent <em class="bcp14">MAY</em> then make its own decision regarding whether or not to redirect the request.
    1441       </p>
    1442       <p id="rfc.section.7.6.p.9">A PUT request applied to the target resource <em class="bcp14">MAY</em> have side-effects on other resources. For example, an article might have a URI for identifying "the current version" (a resource)
    1443          which is separate from the URIs identifying each particular version (different resources that at one point shared the same
    1444          state as the current version resource). A successful PUT request on "the current version" URI might therefore create a new
    1445          version resource in addition to changing the state of the target resource, and might also cause links to be added between
    1446          the related resources.
    1447       </p>
    1448       <p id="rfc.section.7.6.p.10">An origin server <em class="bcp14">SHOULD</em> reject any PUT request that contains a Content-Range header field, since it might be misinterpreted as partial content (or
    1449          might be partial content that is being mistakenly PUT as a full representation). Partial content updates are possible by targeting
    1450          a separately identified resource with state that overlaps a portion of the larger resource, or by using a different method
    1451          that has been specifically defined for partial updates (for example, the PATCH method defined in <a href="#RFC5789" id="rfc.xref.RFC5789.1"><cite title="PATCH Method for HTTP">[RFC5789]</cite></a>).
    1452       </p>
    1453       <p id="rfc.section.7.6.p.11">Responses to the PUT method are not cacheable. If a PUT request passes through a cache that has one or more stored responses
    1454          for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 2.5</a> of <a href="#Part6" id="rfc.xref.Part6.9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    1455       </p>
    1456       <div id="rfc.iref.d.1"></div>
    1457       <div id="rfc.iref.m.6"></div>
    1458       <h2 id="rfc.section.7.7"><a href="#rfc.section.7.7">7.7</a>&nbsp;<a id="DELETE" href="#DELETE">DELETE</a></h2>
    1459       <p id="rfc.section.7.7.p.1">The DELETE method requests that the origin server delete the target resource. This method <em class="bcp14">MAY</em> be overridden by human intervention (or other means) on the origin server. The client cannot be guaranteed that the operation
    1460          has been carried out, even if the status code returned from the origin server indicates that the action has been completed
    1461          successfully. However, the server <em class="bcp14">SHOULD NOT</em> indicate success unless, at the time the response is given, it intends to delete the resource or move it to an inaccessible
    1462          location.
    1463       </p>
    1464       <p id="rfc.section.7.7.p.2">A successful response <em class="bcp14">SHOULD</em> be 200 (OK) if the response includes an representation describing the status, 202 (Accepted) if the action has not yet been
    1465          enacted, or 204 (No Content) if the action has been enacted but the response does not include a representation.
    1466       </p>
    1467       <p id="rfc.section.7.7.p.3">Bodies on DELETE requests have no defined semantics. Note that sending a body on a DELETE request might cause some existing
    1468          implementations to reject the request.
    1469       </p>
    1470       <p id="rfc.section.7.7.p.4">Responses to the DELETE method are not cacheable. If a DELETE request passes through a cache that has one or more stored responses
    1471          for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 2.5</a> of <a href="#Part6" id="rfc.xref.Part6.10"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    1472       </p>
    1473       <h2 id="rfc.section.7.8"><a href="#rfc.section.7.8">7.8</a>&nbsp;<a id="TRACE" href="#TRACE">TRACE</a></h2>
    1474       <div id="rfc.iref.t.1"></div>
    1475       <div id="rfc.iref.m.7"></div>
    1476       <p id="rfc.section.7.8.p.1">The TRACE method requests a remote, application-layer loop-back of the request message. The final recipient of the request <em class="bcp14">SHOULD</em> reflect the message received back to the client as the message-body of a 200 (OK) response. The final recipient is either
    1477          the origin server or the first proxy to receive a Max-Forwards value of zero (0) in the request (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.3" title="Max-Forwards">Section&nbsp;9.5</a>). A TRACE request <em class="bcp14">MUST NOT</em> include a message-body.
    1478       </p>
    1479       <p id="rfc.section.7.8.p.2">TRACE allows the client to see what is being received at the other end of the request chain and use that data for testing
    1480          or diagnostic information. The value of the Via header field (<a href="p1-messaging.html#header.via" title="Via">Section 9.9</a> of <a href="#Part1" id="rfc.xref.Part1.22"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) is of particular interest, since it acts as a trace of the request chain. Use of the Max-Forwards header field allows the
    1481          client to limit the length of the request chain, which is useful for testing a chain of proxies forwarding messages in an
    1482          infinite loop.
    1483       </p>
    1484       <p id="rfc.section.7.8.p.3">If the request is valid, the response <em class="bcp14">SHOULD</em> have a Content-Type of "message/http" (see <a href="p1-messaging.html#internet.media.type.message.http" title="Internet Media Type message/http">Section 10.3.1</a> of <a href="#Part1" id="rfc.xref.Part1.23"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) and contain a message-body that encloses a copy of the entire request message. Responses to the TRACE method are not cacheable.
    1485       </p>
    1486       <div id="rfc.iref.c.1"></div>
    1487       <div id="rfc.iref.m.8"></div>
    1488       <h2 id="rfc.section.7.9"><a href="#rfc.section.7.9">7.9</a>&nbsp;<a id="CONNECT" href="#CONNECT">CONNECT</a></h2>
    1489       <p id="rfc.section.7.9.p.1">The CONNECT method requests that the proxy establish a tunnel to the request-target and then restrict its behavior to blind
    1490          forwarding of packets until the connection is closed.
    1491       </p>
    1492       <p id="rfc.section.7.9.p.2">When using CONNECT, the request-target <em class="bcp14">MUST</em> use the authority form (<a href="p1-messaging.html#request-target" title="request-target">Section 4.1.2</a> of <a href="#Part1" id="rfc.xref.Part1.24"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>); i.e., the request-target consists of only the host name and port number of the tunnel destination, separated by a colon.
    1493          For example,
    1494       </p>
    1495       <div id="rfc.figure.u.5"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
     1283      <div id="representation">
     1284         <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a>&nbsp;<a href="#representation">Representation</a></h1>
     1285         <p id="rfc.section.6.p.1">Request and Response messages <em class="bcp14">MAY</em> transfer a representation if not otherwise restricted by the request method or response status code. A representation consists
     1286            of metadata (representation header fields) and data (representation body). When a complete or partial representation is enclosed
     1287            in an HTTP message, it is referred to as the payload of the message. HTTP representations are defined in <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>.
     1288         </p>
     1289         <p id="rfc.section.6.p.2">A representation body is only present in a message when a message-body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.20"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. The representation body is obtained from the message-body by decoding any Transfer-Encoding that might have been applied
     1290            to ensure safe and proper transfer of the message.
     1291         </p>
     1292         <div id="identifying.response.associated.with.representation">
     1293            <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a>&nbsp;<a href="#identifying.response.associated.with.representation">Identifying the Resource Associated with a Representation</a></h2>
     1294            <p id="rfc.section.6.1.p.1">It is sometimes necessary to determine an identifier for the resource associated with a representation.</p>
     1295            <p id="rfc.section.6.1.p.2">An HTTP request representation, when present, is always associated with an anonymous (i.e., unidentified) resource.</p>
     1296            <p id="rfc.section.6.1.p.3">In the common case, an HTTP response is a representation of the target resource (see <a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.21"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). However, this is not always the case. To determine the URI of the resource a response is associated with, the following
     1297               rules are used (with the first applicable one being selected):
     1298            </p>
     1299            <ol>
     1300               <li>If the response status code is 200 or 203 and the request method was GET, the response payload is a representation of the
     1301                  target resource.
     1302               </li>
     1303               <li>If the response status code is 204, 206, or 304 and the request method was GET or HEAD, the response payload is a partial
     1304                  representation of the target resource (see <a href="p6-cache.html#combining.responses" title="Combining Responses">Section 2.8</a> of <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1305               </li>
     1306               <li>If the response has a Content-Location header field, and that URI is the same as the effective request URI, the response payload
     1307                  is a representation of the target resource.
     1308               </li>
     1309               <li>If the response has a Content-Location header field, and that URI is not the same as the effective request URI, then the response
     1310                  asserts that its payload is a representation of the resource identified by the Content-Location URI. However, such an assertion
     1311                  cannot be trusted unless it can be verified by other means (not defined by HTTP).
     1312               </li>
     1313               <li>Otherwise, the response is a representation of an anonymous (i.e., unidentified) resource.</li>
     1314            </ol>
     1315            <p id="rfc.section.6.1.p.5"><span class="comment" id="TODO-req-uri">[<a href="#TODO-req-uri" class="smpl">TODO-req-uri</a>: The comparison function is going to have to be defined somewhere, because we already need to compare URIs for things like
     1316                  cache invalidation.]</span>
     1317            </p>
     1318         </div>
     1319      </div>
     1320      <div id="method.definitions">
     1321         <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a>&nbsp;<a href="#method.definitions">Method Definitions</a></h1>
     1322         <p id="rfc.section.7.p.1">The set of common request methods for HTTP/1.1 is defined below. Although this set can be expanded, additional methods cannot
     1323            be assumed to share the same semantics for separately extended clients and servers.
     1324         </p>
     1325         <div id="safe.and.idempotent">
     1326            <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a>&nbsp;<a href="#safe.and.idempotent">Safe and Idempotent Methods</a></h2>
     1327            <div id="safe.methods">
     1328               <div id="rfc.iref.s.1"></div>
     1329               <h3 id="rfc.section.7.1.1"><a href="#rfc.section.7.1.1">7.1.1</a>&nbsp;<a href="#safe.methods">Safe Methods</a></h3>
     1330               <p id="rfc.section.7.1.1.p.1">Implementors need to be aware that the software represents the user in their interactions over the Internet, and need to allow
     1331                  the user to be aware of any actions they take which might have an unexpected significance to themselves or others.
     1332               </p>
     1333               <p id="rfc.section.7.1.1.p.2">In particular, the convention has been established that the GET, HEAD, OPTIONS, and TRACE request methods <em class="bcp14">SHOULD NOT</em> have the significance of taking an action other than retrieval. These request methods ought to be considered "<dfn id="safe">safe</dfn>". This allows user agents to represent other methods, such as POST, PUT and DELETE, in a special way, so that the user is
     1334                  made aware of the fact that a possibly unsafe action is being requested.
     1335               </p>
     1336               <p id="rfc.section.7.1.1.p.3">Naturally, it is not possible to ensure that the server does not generate side-effects as a result of performing a GET request;
     1337                  in fact, some dynamic resources consider that a feature. The important distinction here is that the user did not request the
     1338                  side-effects, so therefore cannot be held accountable for them.
     1339               </p>
     1340            </div>
     1341            <div id="idempotent.methods">
     1342               <div id="rfc.iref.i.1"></div>
     1343               <h3 id="rfc.section.7.1.2"><a href="#rfc.section.7.1.2">7.1.2</a>&nbsp;<a href="#idempotent.methods">Idempotent Methods</a></h3>
     1344               <p id="rfc.section.7.1.2.p.1">Request methods can also have the property of "idempotence" in that, aside from error or expiration issues, the intended effect
     1345                  of multiple identical requests is the same as for a single request. PUT, DELETE, and all safe request methods are idempotent.
     1346                  It is important to note that idempotence refers only to changes requested by the client: a server is free to change its state
     1347                  due to multiple requests for the purpose of tracking those requests, versioning of results, etc.
     1348               </p>
     1349            </div>
     1350         </div>
     1351         <div id="OPTIONS">
     1352            <h2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a>&nbsp;<a href="#OPTIONS">OPTIONS</a></h2>
     1353            <div id="rfc.iref.o.1"></div>
     1354            <div id="rfc.iref.m.1"></div>
     1355            <p id="rfc.section.7.2.p.1">The OPTIONS method requests information about the communication options available on the request/response chain identified
     1356               by the effective request URI. This method allows a client to determine the options and/or requirements associated with a resource,
     1357               or the capabilities of a server, without implying a resource action or initiating a resource retrieval.
     1358            </p>
     1359            <p id="rfc.section.7.2.p.2">Responses to the OPTIONS method are not cacheable.</p>
     1360            <p id="rfc.section.7.2.p.3">If the OPTIONS request includes a message-body (as indicated by the presence of Content-Length or Transfer-Encoding), then
     1361               the media type <em class="bcp14">MUST</em> be indicated by a Content-Type field. Although this specification does not define any use for such a body, future extensions
     1362               to HTTP might use the OPTIONS body to make more detailed queries on the server.
     1363            </p>
     1364            <p id="rfc.section.7.2.p.4">If the request-target is an asterisk ("*"), the OPTIONS request is intended to apply to the server in general rather than
     1365               to a specific resource. Since a server's communication options typically depend on the resource, the "*" request is only useful
     1366               as a "ping" or "no-op" type of method; it does nothing beyond allowing the client to test the capabilities of the server.
     1367               For example, this can be used to test a proxy for HTTP/1.1 compliance (or lack thereof).
     1368            </p>
     1369            <p id="rfc.section.7.2.p.5">If the request-target is not an asterisk, the OPTIONS request applies only to the options that are available when communicating
     1370               with that resource.
     1371            </p>
     1372            <p id="rfc.section.7.2.p.6">A 200 response <em class="bcp14">SHOULD</em> include any header fields that indicate optional features implemented by the server and applicable to that resource (e.g.,
     1373               Allow), possibly including extensions not defined by this specification. The response body, if any, <em class="bcp14">SHOULD</em> also include information about the communication options. The format for such a body is not defined by this specification,
     1374               but might be defined by future extensions to HTTP. Content negotiation <em class="bcp14">MAY</em> be used to select the appropriate response format. If no response body is included, the response <em class="bcp14">MUST</em> include a Content-Length field with a field-value of "0".
     1375            </p>
     1376            <p id="rfc.section.7.2.p.7">The Max-Forwards header field <em class="bcp14">MAY</em> be used to target a specific proxy in the request chain (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.2" title="Max-Forwards">Section&nbsp;9.5</a>). If no Max-Forwards field is present in the request, then the forwarded request <em class="bcp14">MUST NOT</em> include a Max-Forwards field.
     1377            </p>
     1378         </div>
     1379         <div id="GET">
     1380            <h2 id="rfc.section.7.3"><a href="#rfc.section.7.3">7.3</a>&nbsp;<a href="#GET">GET</a></h2>
     1381            <div id="rfc.iref.g.5"></div>
     1382            <div id="rfc.iref.m.2"></div>
     1383            <p id="rfc.section.7.3.p.1">The GET method requests transfer of a current representation of the target resource.</p>
     1384            <p id="rfc.section.7.3.p.2">If the target resource is a data-producing process, it is the produced data which shall be returned as the representation
     1385               in the response and not the source text of the process, unless that text happens to be the output of the process.
     1386            </p>
     1387            <p id="rfc.section.7.3.p.3">The semantics of the GET method change to a "conditional GET" if the request message includes an If-Modified-Since, If-Unmodified-Since,
     1388               If-Match, If-None-Match, or If-Range header field. A conditional GET requests that the representation be transferred only
     1389               under the circumstances described by the conditional header field(s). The conditional GET request is intended to reduce unnecessary
     1390               network usage by allowing cached representations to be refreshed without requiring multiple requests or transferring data
     1391               already held by the client.
     1392            </p>
     1393            <p id="rfc.section.7.3.p.4">The semantics of the GET method change to a "partial GET" if the request message includes a Range header field. A partial
     1394               GET requests that only part of the representation be transferred, as described in <a href="p5-range.html#header.range" title="Range">Section 5.4</a> of <a href="#Part5" id="rfc.xref.Part5.7"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>. The partial GET request is intended to reduce unnecessary network usage by allowing partially-retrieved representations
     1395               to be completed without transferring data already held by the client.
     1396            </p>
     1397            <p id="rfc.section.7.3.p.5">Bodies on GET requests have no defined semantics. Note that sending a body on a GET request might cause some existing implementations
     1398               to reject the request.
     1399            </p>
     1400            <p id="rfc.section.7.3.p.6">The response to a GET request is cacheable and <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests (see <a href="#Part6" id="rfc.xref.Part6.6"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1401            </p>
     1402            <p id="rfc.section.7.3.p.7">See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;11.2</a> for security considerations when used for forms.
     1403            </p>
     1404         </div>
     1405         <div id="HEAD">
     1406            <h2 id="rfc.section.7.4"><a href="#rfc.section.7.4">7.4</a>&nbsp;<a href="#HEAD">HEAD</a></h2>
     1407            <div id="rfc.iref.h.1"></div>
     1408            <div id="rfc.iref.m.3"></div>
     1409            <p id="rfc.section.7.4.p.1">The HEAD method is identical to GET except that the server <em class="bcp14">MUST NOT</em> return a message-body in the response. The metadata contained in the HTTP header fields in response to a HEAD request <em class="bcp14">SHOULD</em> be identical to the information sent in response to a GET request. This method can be used for obtaining metadata about the
     1410               representation implied by the request without transferring the representation body. This method is often used for testing
     1411               hypertext links for validity, accessibility, and recent modification.
     1412            </p>
     1413            <p id="rfc.section.7.4.p.2">The response to a HEAD request is cacheable and <em class="bcp14">MAY</em> be used to satisfy a subsequent HEAD request; see <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>. It also <em class="bcp14">MAY</em> be used to update a previously cached representation from that resource; if the new field values indicate that the cached
     1414               representation differs from the current representation (as would be indicated by a change in Content-Length, Content-MD5,
     1415               ETag or Last-Modified), then the cache <em class="bcp14">MUST</em> treat the cache entry as stale.
     1416            </p>
     1417            <p id="rfc.section.7.4.p.3">Bodies on HEAD requests have no defined semantics. Note that sending a body on a HEAD request might cause some existing implementations
     1418               to reject the request.
     1419            </p>
     1420         </div>
     1421         <div id="POST">
     1422            <div id="rfc.iref.p.1"></div>
     1423            <div id="rfc.iref.m.4"></div>
     1424            <h2 id="rfc.section.7.5"><a href="#rfc.section.7.5">7.5</a>&nbsp;<a href="#POST">POST</a></h2>
     1425            <p id="rfc.section.7.5.p.1">The POST method requests that the origin server accept the representation enclosed in the request as data to be processed
     1426               by the target resource. POST is designed to allow a uniform method to cover the following functions:
     1427            </p>
     1428            <ul>
     1429               <li>Annotation of existing resources;</li>
     1430               <li>Posting a message to a bulletin board, newsgroup, mailing list, or similar group of articles;</li>
     1431               <li>Providing a block of data, such as the result of submitting a form, to a data-handling process;</li>
     1432               <li>Extending a database through an append operation.</li>
     1433            </ul>
     1434            <p id="rfc.section.7.5.p.2">The actual function performed by the POST method is determined by the server and is usually dependent on the effective request
     1435               URI.
     1436            </p>
     1437            <p id="rfc.section.7.5.p.3">The action performed by the POST method might not result in a resource that can be identified by a URI. In this case, either
     1438               200 (OK) or 204 (No Content) is the appropriate response status code, depending on whether or not the response includes a
     1439               representation that describes the result.
     1440            </p>
     1441            <p id="rfc.section.7.5.p.4">If a resource has been created on the origin server, the response <em class="bcp14">SHOULD</em> be 201 (Created) and contain a representation which describes the status of the request and refers to the new resource, and
     1442               a Location header field (see <a href="#header.location" id="rfc.xref.header.location.2" title="Location">Section&nbsp;9.4</a>).
     1443            </p>
     1444            <p id="rfc.section.7.5.p.5">Responses to POST requests are only cacheable when they include explicit freshness information (see <a href="p6-cache.html#calculating.freshness.lifetime" title="Calculating Freshness Lifetime">Section 2.3.1</a> of <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). A cached POST response with a Content-Location header field (see <a href="p3-payload.html#header.content-location" title="Content-Location">Section 6.7</a> of <a href="#Part3" id="rfc.xref.Part3.6"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) whose value is the effective Request URI <em class="bcp14">MAY</em> be used to satisfy subsequent GET and HEAD requests.
     1445            </p>
     1446            <p id="rfc.section.7.5.p.6">Note that POST caching is not widely implemented. However, the 303 (See Other) response can be used to direct the user agent
     1447               to retrieve a cacheable resource.
     1448            </p>
     1449         </div>
     1450         <div id="PUT">
     1451            <div id="rfc.iref.p.2"></div>
     1452            <div id="rfc.iref.m.5"></div>
     1453            <h2 id="rfc.section.7.6"><a href="#rfc.section.7.6">7.6</a>&nbsp;<a href="#PUT">PUT</a></h2>
     1454            <p id="rfc.section.7.6.p.1">The PUT method requests that the state of the target resource be created or replaced with the state defined by the representation
     1455               enclosed in the request message payload. A successful PUT of a given representation would suggest that a subsequent GET on
     1456               that same target resource will result in an equivalent representation being returned in a 200 (OK) response. However, there
     1457               is no guarantee that such a state change will be observable, since the target resource might be acted upon by other user agents
     1458               in parallel, or might be subject to dynamic processing by the origin server, before any subsequent GET is received. A successful
     1459               response only implies that the user agent's intent was achieved at the time of its processing by the origin server.
     1460            </p>
     1461            <p id="rfc.section.7.6.p.2">If the target resource does not have a current representation and the PUT successfully creates one, then the origin server <em class="bcp14">MUST</em> inform the user agent by sending a 201 (Created) response. If the target resource does have a current representation and that
     1462               representation is successfully modified in accordance with the state of the enclosed representation, then either a 200 (OK)
     1463               or 204 (No Content) response <em class="bcp14">SHOULD</em> be sent to indicate successful completion of the request.
     1464            </p>
     1465            <p id="rfc.section.7.6.p.3">Unrecognized header fields <em class="bcp14">SHOULD</em> be ignored (i.e., not saved as part of the resource state).
     1466            </p>
     1467            <p id="rfc.section.7.6.p.4">An origin server <em class="bcp14">SHOULD</em> verify that the PUT representation is consistent with any constraints which the server has for the target resource that cannot
     1468               or will not be changed by the PUT. This is particularly important when the origin server uses internal configuration information
     1469               related to the URI in order to set the values for representation metadata on GET responses. When a PUT representation is inconsistent
     1470               with the target resource, the origin server <em class="bcp14">SHOULD</em> either make them consistent, by transforming the representation or changing the resource configuration, or respond with an
     1471               appropriate error message containing sufficient information to explain why the representation is unsuitable. The 409 (Conflict)
     1472               or 415 (Unsupported Media Type) status codes are suggested, with the latter being specific to constraints on Content-Type
     1473               values.
     1474            </p>
     1475            <p id="rfc.section.7.6.p.5">For example, if the target resource is configured to always have a Content-Type of "text/html" and the representation being
     1476               PUT has a Content-Type of "image/jpeg", then the origin server <em class="bcp14">SHOULD</em> do one of: (a) reconfigure the target resource to reflect the new media type; (b) transform the PUT representation to a format
     1477               consistent with that of the resource before saving it as the new resource state; or, (c) reject the request with a 415 response
     1478               indicating that the target resource is limited to "text/html", perhaps including a link to a different resource that would
     1479               be a suitable target for the new representation.
     1480            </p>
     1481            <p id="rfc.section.7.6.p.6">HTTP does not define exactly how a PUT method affects the state of an origin server beyond what can be expressed by the intent
     1482               of the user agent request and the semantics of the origin server response. It does not define what a resource might be, in
     1483               any sense of that word, beyond the interface provided via HTTP. It does not define how resource state is "stored", nor how
     1484               such storage might change as a result of a change in resource state, nor how the origin server translates resource state into
     1485               representations. Generally speaking, all implementation details behind the resource interface are intentionally hidden by
     1486               the server.
     1487            </p>
     1488            <p id="rfc.section.7.6.p.7">The fundamental difference between the POST and PUT methods is highlighted by the different intent for the target resource.
     1489               The target resource in a POST request is intended to handle the enclosed representation as a data-accepting process, such
     1490               as for a gateway to some other protocol or a document that accepts annotations. In contrast, the target resource in a PUT
     1491               request is intended to take the enclosed representation as a new or replacement value. Hence, the intent of PUT is idempotent
     1492               and visible to intermediaries, even though the exact effect is only known by the origin server.
     1493            </p>
     1494            <p id="rfc.section.7.6.p.8">Proper interpretation of a PUT request presumes that the user agent knows what target resource is desired. A service that
     1495               is intended to select a proper URI on behalf of the client, after receiving a state-changing request, <em class="bcp14">SHOULD</em> be implemented using the POST method rather than PUT. If the origin server will not make the requested PUT state change to
     1496               the target resource and instead wishes to have it applied to a different resource, such as when the resource has been moved
     1497               to a different URI, then the origin server <em class="bcp14">MUST</em> send a 301 (Moved Permanently) response; the user agent <em class="bcp14">MAY</em> then make its own decision regarding whether or not to redirect the request.
     1498            </p>
     1499            <p id="rfc.section.7.6.p.9">A PUT request applied to the target resource <em class="bcp14">MAY</em> have side-effects on other resources. For example, an article might have a URI for identifying "the current version" (a resource)
     1500               which is separate from the URIs identifying each particular version (different resources that at one point shared the same
     1501               state as the current version resource). A successful PUT request on "the current version" URI might therefore create a new
     1502               version resource in addition to changing the state of the target resource, and might also cause links to be added between
     1503               the related resources.
     1504            </p>
     1505            <p id="rfc.section.7.6.p.10">An origin server <em class="bcp14">SHOULD</em> reject any PUT request that contains a Content-Range header field, since it might be misinterpreted as partial content (or
     1506               might be partial content that is being mistakenly PUT as a full representation). Partial content updates are possible by targeting
     1507               a separately identified resource with state that overlaps a portion of the larger resource, or by using a different method
     1508               that has been specifically defined for partial updates (for example, the PATCH method defined in <a href="#RFC5789" id="rfc.xref.RFC5789.1"><cite title="PATCH Method for HTTP">[RFC5789]</cite></a>).
     1509            </p>
     1510            <p id="rfc.section.7.6.p.11">Responses to the PUT method are not cacheable. If a PUT request passes through a cache that has one or more stored responses
     1511               for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 2.5</a> of <a href="#Part6" id="rfc.xref.Part6.9"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1512            </p>
     1513         </div>
     1514         <div id="DELETE">
     1515            <div id="rfc.iref.d.1"></div>
     1516            <div id="rfc.iref.m.6"></div>
     1517            <h2 id="rfc.section.7.7"><a href="#rfc.section.7.7">7.7</a>&nbsp;<a href="#DELETE">DELETE</a></h2>
     1518            <p id="rfc.section.7.7.p.1">The DELETE method requests that the origin server delete the target resource. This method <em class="bcp14">MAY</em> be overridden by human intervention (or other means) on the origin server. The client cannot be guaranteed that the operation
     1519               has been carried out, even if the status code returned from the origin server indicates that the action has been completed
     1520               successfully. However, the server <em class="bcp14">SHOULD NOT</em> indicate success unless, at the time the response is given, it intends to delete the resource or move it to an inaccessible
     1521               location.
     1522            </p>
     1523            <p id="rfc.section.7.7.p.2">A successful response <em class="bcp14">SHOULD</em> be 200 (OK) if the response includes an representation describing the status, 202 (Accepted) if the action has not yet been
     1524               enacted, or 204 (No Content) if the action has been enacted but the response does not include a representation.
     1525            </p>
     1526            <p id="rfc.section.7.7.p.3">Bodies on DELETE requests have no defined semantics. Note that sending a body on a DELETE request might cause some existing
     1527               implementations to reject the request.
     1528            </p>
     1529            <p id="rfc.section.7.7.p.4">Responses to the DELETE method are not cacheable. If a DELETE request passes through a cache that has one or more stored responses
     1530               for the effective request URI, those stored responses will be invalidated (see <a href="p6-cache.html#invalidation.after.updates.or.deletions" title="Request Methods that Invalidate">Section 2.5</a> of <a href="#Part6" id="rfc.xref.Part6.10"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1531            </p>
     1532         </div>
     1533         <div id="TRACE">
     1534            <h2 id="rfc.section.7.8"><a href="#rfc.section.7.8">7.8</a>&nbsp;<a href="#TRACE">TRACE</a></h2>
     1535            <div id="rfc.iref.t.1"></div>
     1536            <div id="rfc.iref.m.7"></div>
     1537            <p id="rfc.section.7.8.p.1">The TRACE method requests a remote, application-layer loop-back of the request message. The final recipient of the request <em class="bcp14">SHOULD</em> reflect the message received back to the client as the message-body of a 200 (OK) response. The final recipient is either
     1538               the origin server or the first proxy to receive a Max-Forwards value of zero (0) in the request (see <a href="#header.max-forwards" id="rfc.xref.header.max-forwards.3" title="Max-Forwards">Section&nbsp;9.5</a>). A TRACE request <em class="bcp14">MUST NOT</em> include a message-body.
     1539            </p>
     1540            <p id="rfc.section.7.8.p.2">TRACE allows the client to see what is being received at the other end of the request chain and use that data for testing
     1541               or diagnostic information. The value of the Via header field (<a href="p1-messaging.html#header.via" title="Via">Section 9.9</a> of <a href="#Part1" id="rfc.xref.Part1.22"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) is of particular interest, since it acts as a trace of the request chain. Use of the Max-Forwards header field allows the
     1542               client to limit the length of the request chain, which is useful for testing a chain of proxies forwarding messages in an
     1543               infinite loop.
     1544            </p>
     1545            <p id="rfc.section.7.8.p.3">If the request is valid, the response <em class="bcp14">SHOULD</em> have a Content-Type of "message/http" (see <a href="p1-messaging.html#internet.media.type.message.http" title="Internet Media Type message/http">Section 10.3.1</a> of <a href="#Part1" id="rfc.xref.Part1.23"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) and contain a message-body that encloses a copy of the entire request message. Responses to the TRACE method are not cacheable.
     1546            </p>
     1547         </div>
     1548         <div id="CONNECT">
     1549            <div id="rfc.iref.c.1"></div>
     1550            <div id="rfc.iref.m.8"></div>
     1551            <h2 id="rfc.section.7.9"><a href="#rfc.section.7.9">7.9</a>&nbsp;<a href="#CONNECT">CONNECT</a></h2>
     1552            <p id="rfc.section.7.9.p.1">The CONNECT method requests that the proxy establish a tunnel to the request-target and then restrict its behavior to blind
     1553               forwarding of packets until the connection is closed.
     1554            </p>
     1555            <p id="rfc.section.7.9.p.2">When using CONNECT, the request-target <em class="bcp14">MUST</em> use the authority form (<a href="p1-messaging.html#request-target" title="request-target">Section 4.1.2</a> of <a href="#Part1" id="rfc.xref.Part1.24"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>); i.e., the request-target consists of only the host name and port number of the tunnel destination, separated by a colon.
     1556               For example,
     1557            </p>
     1558            <div id="rfc.figure.u.5"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
    14961559Host: server.example.com:80
    14971560
    14981561</pre><p id="rfc.section.7.9.p.4">Other HTTP mechanisms can be used normally with the CONNECT method — except end-to-end protocol Upgrade requests, since the
    1499          tunnel must be established first.
    1500       </p>
    1501       <p id="rfc.section.7.9.p.5">For example, proxy authentication might be used to establish the authority to create a tunnel:</p>
    1502       <div id="rfc.figure.u.6"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
     1562               tunnel must be established first.
     1563            </p>
     1564            <p id="rfc.section.7.9.p.5">For example, proxy authentication might be used to establish the authority to create a tunnel:</p>
     1565            <div id="rfc.figure.u.6"></div><pre class="text2">CONNECT server.example.com:80 HTTP/1.1
    15031566Host: server.example.com:80
    15041567Proxy-Authorization: basic aGVsbG86d29ybGQ=
    15051568
    15061569</pre><p id="rfc.section.7.9.p.7">Bodies on CONNECT requests have no defined semantics. Note that sending a body on a CONNECT request might cause some existing
    1507          implementations to reject the request.
    1508       </p>
    1509       <p id="rfc.section.7.9.p.8">Like any other pipelined HTTP/1.1 request, data to be tunnel may be sent immediately after the blank line. The usual caveats
    1510          also apply: data may be discarded if the eventual response is negative, and the connection may be reset with no response if
    1511          more than one TCP segment is outstanding.
    1512       </p>
    1513       <h3 id="rfc.section.7.9.1"><a href="#rfc.section.7.9.1">7.9.1</a>&nbsp;Establishing a Tunnel with CONNECT
    1514       </h3>
    1515       <p id="rfc.section.7.9.1.p.1">Any successful (2xx) response to a CONNECT request indicates that the proxy has established a connection to the requested
    1516          host and port, and has switched to tunneling the current connection to that server connection.
    1517       </p>
    1518       <p id="rfc.section.7.9.1.p.2">It may be the case that the proxy itself can only reach the requested origin server through another proxy. In this case, the
    1519          first proxy <em class="bcp14">SHOULD</em> make a CONNECT request of that next proxy, requesting a tunnel to the authority. A proxy <em class="bcp14">MUST NOT</em> respond with any 2xx status code unless it has either a direct or tunnel connection established to the authority.
    1520       </p>
    1521       <p id="rfc.section.7.9.1.p.3">An origin server which receives a CONNECT request for itself <em class="bcp14">MAY</em> respond with a 2xx status code to indicate that a connection is established.
    1522       </p>
    1523       <p id="rfc.section.7.9.1.p.4">If at any point either one of the peers gets disconnected, any outstanding data that came from that peer will be passed to
    1524          the other one, and after that also the other connection will be terminated by the proxy. If there is outstanding data to that
    1525          peer undelivered, that data will be discarded.
    1526       </p>
    1527       <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a id="status.codes" href="#status.codes">Status Code Definitions</a></h1>
    1528       <p id="rfc.section.8.p.1">Each Status-Code is described below, including any metadata required in the response.</p>
    1529       <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a>&nbsp;<a id="status.1xx" href="#status.1xx">Informational 1xx</a></h2>
    1530       <p id="rfc.section.8.1.p.1">This class of status code indicates a provisional response, consisting only of the Status-Line and optional header fields,
    1531          and is terminated by an empty line. There are no required header fields for this class of status code. Since HTTP/1.0 did
    1532          not define any 1xx status codes, servers <em class="bcp14">MUST NOT</em> send a 1xx response to an HTTP/1.0 client except under experimental conditions.
    1533       </p>
    1534       <p id="rfc.section.8.1.p.2">A client <em class="bcp14">MUST</em> be prepared to accept one or more 1xx status responses prior to a regular response, even if the client does not expect a 100
    1535          (Continue) status message. Unexpected 1xx status responses <em class="bcp14">MAY</em> be ignored by a user agent.
    1536       </p>
    1537       <p id="rfc.section.8.1.p.3">Proxies <em class="bcp14">MUST</em> forward 1xx responses, unless the connection between the proxy and its client has been closed, or unless the proxy itself
    1538          requested the generation of the 1xx response. (For example, if a proxy adds a "Expect: 100-continue" field when it forwards
    1539          a request, then it need not forward the corresponding 100 (Continue) response(s).)
    1540       </p>
    1541       <div id="rfc.iref.22"></div>
    1542       <div id="rfc.iref.s.2"></div>
    1543       <h3 id="rfc.section.8.1.1"><a href="#rfc.section.8.1.1">8.1.1</a>&nbsp;<a id="status.100" href="#status.100">100 Continue</a></h3>
    1544       <p id="rfc.section.8.1.1.p.1">The client <em class="bcp14">SHOULD</em> continue with its request. This interim response is used to inform the client that the initial part of the request has been
    1545          received and has not yet been rejected by the server. The client <em class="bcp14">SHOULD</em> continue by sending the remainder of the request or, if the request has already been completed, ignore this response. The
    1546          server <em class="bcp14">MUST</em> send a final response after the request has been completed. See <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 7.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.25"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> for detailed discussion of the use and handling of this status code.
    1547       </p>
    1548       <div id="rfc.iref.23"></div>
    1549       <div id="rfc.iref.s.3"></div>
    1550       <h3 id="rfc.section.8.1.2"><a href="#rfc.section.8.1.2">8.1.2</a>&nbsp;<a id="status.101" href="#status.101">101 Switching Protocols</a></h3>
    1551       <p id="rfc.section.8.1.2.p.1">The server understands and is willing to comply with the client's request, via the Upgrade message header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 9.8</a> of <a href="#Part1" id="rfc.xref.Part1.26"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>), for a change in the application protocol being used on this connection. The server will switch protocols to those defined
    1552          by the response's Upgrade header field immediately after the empty line which terminates the 101 response.
    1553       </p>
    1554       <p id="rfc.section.8.1.2.p.2">The protocol <em class="bcp14">SHOULD</em> be switched only when it is advantageous to do so. For example, switching to a newer version of HTTP is advantageous over
    1555          older versions, and switching to a real-time, synchronous protocol might be advantageous when delivering resources that use
    1556          such features.
    1557       </p>
    1558       <h2 id="rfc.section.8.2"><a href="#rfc.section.8.2">8.2</a>&nbsp;<a id="status.2xx" href="#status.2xx">Successful 2xx</a></h2>
    1559       <p id="rfc.section.8.2.p.1">This class of status code indicates that the client's request was successfully received, understood, and accepted.</p>
    1560       <div id="rfc.iref.24"></div>
    1561       <div id="rfc.iref.s.4"></div>
    1562       <h3 id="rfc.section.8.2.1"><a href="#rfc.section.8.2.1">8.2.1</a>&nbsp;<a id="status.200" href="#status.200">200 OK</a></h3>
    1563       <p id="rfc.section.8.2.1.p.1">The request has succeeded. The payload returned with the response is dependent on the method used in the request, for example: </p>
    1564       <dl>
    1565          <dt>GET</dt>
    1566          <dd>a representation of the target resource is sent in the response;</dd>
    1567          <dt>HEAD</dt>
    1568          <dd>the same representation as GET, except without the message-body;</dd>
    1569          <dt>POST</dt>
    1570          <dd>a representation describing or containing the result of the action;</dd>
    1571          <dt>TRACE</dt>
    1572          <dd>a representation containing the request message as received by the end server.</dd>
    1573       </dl>
    1574       <p id="rfc.section.8.2.1.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.11"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 200 responses.
    1575       </p>
    1576       <div id="rfc.iref.25"></div>
    1577       <div id="rfc.iref.s.5"></div>
    1578       <h3 id="rfc.section.8.2.2"><a href="#rfc.section.8.2.2">8.2.2</a>&nbsp;<a id="status.201" href="#status.201">201 Created</a></h3>
    1579       <p id="rfc.section.8.2.2.p.1">The request has been fulfilled and has resulted in a new resource being created. The newly created resource can be referenced
    1580          by the URI(s) returned in the payload of the response, with the most specific URI for the resource given by a Location header
    1581          field. The response <em class="bcp14">SHOULD</em> include a payload containing a list of resource characteristics and location(s) from which the user or user agent can choose
    1582          the one most appropriate. The payload format is specified by the media type given in the Content-Type header field. The origin
    1583          server <em class="bcp14">MUST</em> create the resource before returning the 201 status code. If the action cannot be carried out immediately, the server <em class="bcp14">SHOULD</em> respond with 202 (Accepted) response instead.
    1584       </p>
    1585       <p id="rfc.section.8.2.2.p.2">A 201 response <em class="bcp14">MAY</em> contain an ETag response header field indicating the current value of the entity-tag for the representation of the resource
    1586          just created (see <a href="p4-conditional.html#header.etag" title="ETag">Section 2.2</a> of <a href="#Part4" id="rfc.xref.Part4.9"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>).
    1587       </p>
    1588       <div id="rfc.iref.26"></div>
    1589       <div id="rfc.iref.s.6"></div>
    1590       <h3 id="rfc.section.8.2.3"><a href="#rfc.section.8.2.3">8.2.3</a>&nbsp;<a id="status.202" href="#status.202">202 Accepted</a></h3>
    1591       <p id="rfc.section.8.2.3.p.1">The request has been accepted for processing, but the processing has not been completed. The request might or might not eventually
    1592          be acted upon, as it might be disallowed when processing actually takes place. There is no facility for re-sending a status
    1593          code from an asynchronous operation such as this.
    1594       </p>
    1595       <p id="rfc.section.8.2.3.p.2">The 202 response is intentionally non-committal. Its purpose is to allow a server to accept a request for some other process
    1596          (perhaps a batch-oriented process that is only run once per day) without requiring that the user agent's connection to the
    1597          server persist until the process is completed. The representation returned with this response <em class="bcp14">SHOULD</em> include an indication of the request's current status and either a pointer to a status monitor or some estimate of when the
    1598          user can expect the request to be fulfilled.
    1599       </p>
    1600       <div id="rfc.iref.27"></div>
    1601       <div id="rfc.iref.s.7"></div>
    1602       <h3 id="rfc.section.8.2.4"><a href="#rfc.section.8.2.4">8.2.4</a>&nbsp;<a id="status.203" href="#status.203">203 Non-Authoritative Information</a></h3>
    1603       <p id="rfc.section.8.2.4.p.1">The representation in the response has been transformed or otherwise modified by a transforming proxy (<a href="p1-messaging.html#intermediaries" title="Intermediaries">Section 2.4</a> of <a href="#Part1" id="rfc.xref.Part1.27"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). Note that the behaviour of transforming intermediaries is controlled by the no-transform Cache-Control directive (<a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 3.2</a> of <a href="#Part6" id="rfc.xref.Part6.12"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
    1604       </p>
    1605       <p id="rfc.section.8.2.4.p.2">This status code is only appropriate when the response status code would have been 200 (OK) otherwise. When the status code
    1606          before transformation would have been different, the 214 Transformation Applied warn-code (<a href="p6-cache.html#header.warning" title="Warning">Section 3.6</a> of <a href="#Part6" id="rfc.xref.Part6.13"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) is appropriate.
    1607       </p>
    1608       <p id="rfc.section.8.2.4.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.14"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 203 responses.
    1609       </p>
    1610       <div id="rfc.iref.28"></div>
    1611       <div id="rfc.iref.s.8"></div>
    1612       <h3 id="rfc.section.8.2.5"><a href="#rfc.section.8.2.5">8.2.5</a>&nbsp;<a id="status.204" href="#status.204">204 No Content</a></h3>
    1613       <p id="rfc.section.8.2.5.p.1">The 204 (No Content) status code indicates that the server has successfully fulfilled the request and that there is no additional
    1614          content to return in the response payload body. Metadata in the response header fields refer to the target resource and its
    1615          current representation after the requested action.
    1616       </p>
    1617       <p id="rfc.section.8.2.5.p.2">For example, if a 204 status code is received in response to a PUT request and the response contains an ETag header field,
    1618          then the PUT was successful and the ETag field-value contains the entity-tag for the new representation of that target resource.
    1619       </p>
    1620       <p id="rfc.section.8.2.5.p.3">The 204 response allows a server to indicate that the action has been successfully applied to the target resource while implying
    1621          that the user agent <em class="bcp14">SHOULD NOT</em> traverse away from its current "document view" (if any). The server assumes that the user agent will provide some indication
    1622          of the success to its user, in accord with its own interface, and apply any new or updated metadata in the response to the
    1623          active representation.
    1624       </p>
    1625       <p id="rfc.section.8.2.5.p.4">For example, a 204 status code is commonly used with document editing interfaces corresponding to a "save" action, such that
    1626          the document being saved remains available to the user for editing. It is also frequently used with interfaces that expect
    1627          automated data transfers to be prevalent, such as within distributed version control systems.
    1628       </p>
    1629       <p id="rfc.section.8.2.5.p.5">The 204 response <em class="bcp14">MUST NOT</em> include a message-body, and thus is always terminated by the first empty line after the header fields.
    1630       </p>
    1631       <div id="rfc.iref.29"></div>
    1632       <div id="rfc.iref.s.9"></div>
    1633       <h3 id="rfc.section.8.2.6"><a href="#rfc.section.8.2.6">8.2.6</a>&nbsp;<a id="status.205" href="#status.205">205 Reset Content</a></h3>
    1634       <p id="rfc.section.8.2.6.p.1">The server has fulfilled the request and the user agent <em class="bcp14">SHOULD</em> reset the document view which caused the request to be sent. This response is primarily intended to allow input for actions
    1635          to take place via user input, followed by a clearing of the form in which the input is given so that the user can easily initiate
    1636          another input action.
    1637       </p>
    1638       <p id="rfc.section.8.2.6.p.2">The message-body included with the response <em class="bcp14">MUST</em> be empty. Note that receivers still need to parse the response according to the algorithm defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.28"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>.
    1639       </p>
    1640       <div id="rfc.iref.30"></div>
    1641       <div id="rfc.iref.s.10"></div>
    1642       <h3 id="rfc.section.8.2.7"><a href="#rfc.section.8.2.7">8.2.7</a>&nbsp;<a id="status.206" href="#status.206">206 Partial Content</a></h3>
    1643       <p id="rfc.section.8.2.7.p.1">The server has fulfilled the partial GET request for the resource and the enclosed payload is a partial representation as
    1644          defined in <a href="p5-range.html#status.206" title="206 Partial Content">Section 3.1</a> of <a href="#Part5" id="rfc.xref.Part5.8"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>.
    1645       </p>
    1646       <p id="rfc.section.8.2.7.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.15"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 206 responses.
    1647       </p>
    1648       <h2 id="rfc.section.8.3"><a href="#rfc.section.8.3">8.3</a>&nbsp;<a id="status.3xx" href="#status.3xx">Redirection 3xx</a></h2>
    1649       <p id="rfc.section.8.3.p.1">This class of status code indicates that further action needs to be taken by the user agent in order to fulfill the request.
    1650          The action required <em class="bcp14">MAY</em> be carried out by the user agent without interaction with the user if and only if the method used in the second request is
    1651          known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>. A client <em class="bcp14">SHOULD</em> detect infinite redirection loops, since such loops generate network traffic for each redirection.
    1652       </p>
    1653       <div class="note" id="rfc.section.8.3.p.2">
    1654          <p> <b>Note:</b> An earlier version of this specification recommended a maximum of five redirections (<a href="#RFC2068" id="rfc.xref.RFC2068.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, <a href="http://tools.ietf.org/html/rfc2068#section-10.3">Section 10.3</a>). Content developers need to be aware that some clients might implement such a fixed limitation.
    1655          </p>
     1570               implementations to reject the request.
     1571            </p>
     1572            <p id="rfc.section.7.9.p.8">Like any other pipelined HTTP/1.1 request, data to be tunnel may be sent immediately after the blank line. The usual caveats
     1573               also apply: data may be discarded if the eventual response is negative, and the connection may be reset with no response if
     1574               more than one TCP segment is outstanding.
     1575            </p>
     1576            <div>
     1577               <h3 id="rfc.section.7.9.1"><a href="#rfc.section.7.9.1">7.9.1</a>&nbsp;Establishing a Tunnel with CONNECT
     1578               </h3>
     1579               <p id="rfc.section.7.9.1.p.1">Any successful (2xx) response to a CONNECT request indicates that the proxy has established a connection to the requested
     1580                  host and port, and has switched to tunneling the current connection to that server connection.
     1581               </p>
     1582               <p id="rfc.section.7.9.1.p.2">It may be the case that the proxy itself can only reach the requested origin server through another proxy. In this case, the
     1583                  first proxy <em class="bcp14">SHOULD</em> make a CONNECT request of that next proxy, requesting a tunnel to the authority. A proxy <em class="bcp14">MUST NOT</em> respond with any 2xx status code unless it has either a direct or tunnel connection established to the authority.
     1584               </p>
     1585               <p id="rfc.section.7.9.1.p.3">An origin server which receives a CONNECT request for itself <em class="bcp14">MAY</em> respond with a 2xx status code to indicate that a connection is established.
     1586               </p>
     1587               <p id="rfc.section.7.9.1.p.4">If at any point either one of the peers gets disconnected, any outstanding data that came from that peer will be passed to
     1588                  the other one, and after that also the other connection will be terminated by the proxy. If there is outstanding data to that
     1589                  peer undelivered, that data will be discarded.
     1590               </p>
     1591            </div>
     1592         </div>
    16561593      </div>
    1657       <div id="rfc.iref.31"></div>
    1658       <div id="rfc.iref.s.11"></div>
    1659       <h3 id="rfc.section.8.3.1"><a href="#rfc.section.8.3.1">8.3.1</a>&nbsp;<a id="status.300" href="#status.300">300 Multiple Choices</a></h3>
    1660       <p id="rfc.section.8.3.1.p.1">The target resource has more than one representation, each with its own specific location, and agent-driven negotiation information
    1661          (<a href="p3-payload.html#content.negotiation" title="Content Negotiation">Section 5</a> of <a href="#Part3" id="rfc.xref.Part3.7"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) is being provided so that the user (or user agent) can select a preferred representation by redirecting its request to that
    1662          location.
    1663       </p>
    1664       <p id="rfc.section.8.3.1.p.2">Unless it was a HEAD request, the response <em class="bcp14">SHOULD</em> include a representation containing a list of representation metadata and location(s) from which the user or user agent can
    1665          choose the one most appropriate. The data format is specified by the media type given in the Content-Type header field. Depending
    1666          upon the format and the capabilities of the user agent, selection of the most appropriate choice <em class="bcp14">MAY</em> be performed automatically. However, this specification does not define any standard for such automatic selection.
    1667       </p>
    1668       <p id="rfc.section.8.3.1.p.3">If the server has a preferred choice of representation, it <em class="bcp14">SHOULD</em> include the specific URI for that representation in the Location field; user agents <em class="bcp14">MAY</em> use the Location field value for automatic redirection.
    1669       </p>
    1670       <p id="rfc.section.8.3.1.p.4">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.16"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 300 responses.
    1671       </p>
    1672       <div id="rfc.iref.32"></div>
    1673       <div id="rfc.iref.s.12"></div>
    1674       <h3 id="rfc.section.8.3.2"><a href="#rfc.section.8.3.2">8.3.2</a>&nbsp;<a id="status.301" href="#status.301">301 Moved Permanently</a></h3>
    1675       <p id="rfc.section.8.3.2.p.1">The target resource has been assigned a new permanent URI and any future references to this resource <em class="bcp14">SHOULD</em> use one of the returned URIs. Clients with link editing capabilities ought to automatically re-link references to the effective
    1676          request URI to one or more of the new references returned by the server, where possible.
    1677       </p>
    1678       <p id="rfc.section.8.3.2.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.17"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 301 responses.
    1679       </p>
    1680       <p id="rfc.section.8.3.2.p.3">The new permanent URI <em class="bcp14">SHOULD</em> be given by the Location field in the response. Unless the request method was HEAD, the representation of the response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the new URI(s).
    1681       </p>
    1682       <p id="rfc.section.8.3.2.p.4">If the 301 status code is received in response to a request method that is known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>, then the request <em class="bcp14">MAY</em> be automatically redirected by the user agent without confirmation. Otherwise, the user agent <em class="bcp14">MUST NOT</em> automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which
    1683          the request was issued.
    1684       </p>
    1685       <div class="note" id="rfc.section.8.3.2.p.5">
    1686          <p> <b>Note:</b> When automatically redirecting a POST request after receiving a 301 status code, some existing HTTP/1.0 user agents will erroneously
    1687             change it into a GET request.
    1688          </p>
    1689       </div>
    1690       <div id="rfc.iref.33"></div>
    1691       <div id="rfc.iref.s.13"></div>
    1692       <h3 id="rfc.section.8.3.3"><a href="#rfc.section.8.3.3">8.3.3</a>&nbsp;<a id="status.302" href="#status.302">302 Found</a></h3>
    1693       <p id="rfc.section.8.3.3.p.1">The target resource resides temporarily under a different URI. Since the redirection might be altered on occasion, the client <em class="bcp14">SHOULD</em> continue to use the effective request URI for future requests.
    1694       </p>
    1695       <p id="rfc.section.8.3.3.p.2">The temporary URI <em class="bcp14">SHOULD</em> be given by the Location field in the response. Unless the request method was HEAD, the representation of the response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the new URI(s).
    1696       </p>
    1697       <p id="rfc.section.8.3.3.p.3">If the 302 status code is received in response to a request method that is known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>, then the request <em class="bcp14">MAY</em> be automatically redirected by the user agent without confirmation. Otherwise, the user agent <em class="bcp14">MUST NOT</em> automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which
    1698          the request was issued.
    1699       </p>
    1700       <div class="note" id="rfc.section.8.3.3.p.4">
    1701          <p> <b>Note:</b> HTTP/1.0 (<a href="#RFC1945" id="rfc.xref.RFC1945.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.0">[RFC1945]</cite></a>, <a href="http://tools.ietf.org/html/rfc1945#section-9.3">Section 9.3</a>) and the first version of HTTP/1.1 (<a href="#RFC2068" id="rfc.xref.RFC2068.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, <a href="http://tools.ietf.org/html/rfc2068#section-10.3.3">Section 10.3.3</a>) specify that the client is not allowed to change the method on the redirected request. However, most existing user agent
    1702             implementations treat 302 as if it were a 303 response, performing a GET on the Location field-value regardless of the original
    1703             request method. Therefore, a previous version of this specification (<a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>, <a href="http://tools.ietf.org/html/rfc2616#section-10.3.3">Section 10.3.3</a>) has added the status codes <a href="#status.303" id="rfc.xref.status.303.2">303</a> and <a href="#status.307" id="rfc.xref.status.307.2">307</a> for servers that wish to make unambiguously clear which kind of reaction is expected of the client.
    1704          </p>
    1705       </div>
    1706       <div id="rfc.iref.34"></div>
    1707       <div id="rfc.iref.s.14"></div>
    1708       <h3 id="rfc.section.8.3.4"><a href="#rfc.section.8.3.4">8.3.4</a>&nbsp;<a id="status.303" href="#status.303">303 See Other</a></h3>
    1709       <p id="rfc.section.8.3.4.p.1">The server directs the user agent to a different resource, indicated by a URI in the Location header field, that provides
    1710          an indirect response to the original request. The user agent <em class="bcp14">MAY</em> perform a GET request on the URI in the Location field in order to obtain a representation corresponding to the response,
    1711          be redirected again, or end with an error status. The Location URI is not a substitute reference for the effective request
    1712          URI.
    1713       </p>
    1714       <p id="rfc.section.8.3.4.p.2">The 303 status code is generally applicable to any HTTP method. It is primarily used to allow the output of a POST action
    1715          to redirect the user agent to a selected resource, since doing so provides the information corresponding to the POST response
    1716          in a form that can be separately identified, bookmarked, and cached independent of the original request.
    1717       </p>
    1718       <p id="rfc.section.8.3.4.p.3">A 303 response to a GET request indicates that the requested resource does not have a representation of its own that can be
    1719          transferred by the server over HTTP. The Location URI indicates a resource that is descriptive of the target resource, such
    1720          that the follow-on representation might be useful to recipients without implying that it adequately represents the target
    1721          resource. Note that answers to the questions of what can be represented, what representations are adequate, and what might
    1722          be a useful description are outside the scope of HTTP and thus entirely determined by the URI owner(s).
    1723       </p>
    1724       <p id="rfc.section.8.3.4.p.4">Except for responses to a HEAD request, the representation of a 303 response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the Location URI.
    1725       </p>
    1726       <div id="rfc.iref.35"></div>
    1727       <div id="rfc.iref.s.15"></div>
    1728       <h3 id="rfc.section.8.3.5"><a href="#rfc.section.8.3.5">8.3.5</a>&nbsp;<a id="status.304" href="#status.304">304 Not Modified</a></h3>
    1729       <p id="rfc.section.8.3.5.p.1">The response to the request has not been modified since the conditions indicated by the client's conditional GET request,
    1730          as defined in <a href="p4-conditional.html#status.304" title="304 Not Modified">Section 4.1</a> of <a href="#Part4" id="rfc.xref.Part4.10"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>.
    1731       </p>
    1732       <div id="rfc.iref.36"></div>
    1733       <div id="rfc.iref.s.16"></div>
    1734       <h3 id="rfc.section.8.3.6"><a href="#rfc.section.8.3.6">8.3.6</a>&nbsp;<a id="status.305" href="#status.305">305 Use Proxy</a></h3>
    1735       <p id="rfc.section.8.3.6.p.1">The 305 status code was defined in a previous version of this specification (see <a href="#changes.from.rfc.2616" title="Changes from RFC 2616">Appendix&nbsp;A</a>), and is now deprecated.
    1736       </p>
    1737       <div id="rfc.iref.37"></div>
    1738       <div id="rfc.iref.s.17"></div>
    1739       <h3 id="rfc.section.8.3.7"><a href="#rfc.section.8.3.7">8.3.7</a>&nbsp;<a id="status.306" href="#status.306">306 (Unused)</a></h3>
    1740       <p id="rfc.section.8.3.7.p.1">The 306 status code was used in a previous version of the specification, is no longer used, and the code is reserved.</p>
    1741       <div id="rfc.iref.38"></div>
    1742       <div id="rfc.iref.s.18"></div>
    1743       <h3 id="rfc.section.8.3.8"><a href="#rfc.section.8.3.8">8.3.8</a>&nbsp;<a id="status.307" href="#status.307">307 Temporary Redirect</a></h3>
    1744       <p id="rfc.section.8.3.8.p.1">The target resource resides temporarily under a different URI. Since the redirection can change over time, the client <em class="bcp14">SHOULD</em> continue to use the effective request URI for future requests.
    1745       </p>
    1746       <p id="rfc.section.8.3.8.p.2">The temporary URI <em class="bcp14">SHOULD</em> be given by the Location field in the response. Unless the request method was HEAD, the representation of the response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the new URI(s), since many pre-HTTP/1.1 user agents do not understand the
    1747          307 status code. Therefore, the note <em class="bcp14">SHOULD</em> contain the information necessary for a user to repeat the original request on the new URI.
    1748       </p>
    1749       <p id="rfc.section.8.3.8.p.3">If the 307 status code is received in response to a request method that is known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>, then the request <em class="bcp14">MAY</em> be automatically redirected by the user agent without confirmation. Otherwise, the user agent <em class="bcp14">MUST NOT</em> automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which
    1750          the request was issued.
    1751       </p>
    1752       <h2 id="rfc.section.8.4"><a href="#rfc.section.8.4">8.4</a>&nbsp;<a id="status.4xx" href="#status.4xx">Client Error 4xx</a></h2>
    1753       <p id="rfc.section.8.4.p.1">The 4xx class of status code is intended for cases in which the client seems to have erred. Except when responding to a HEAD
    1754          request, the server <em class="bcp14">SHOULD</em> include a representation containing an explanation of the error situation, and whether it is a temporary or permanent condition.
    1755          These status codes are applicable to any request method. User agents <em class="bcp14">SHOULD</em> display any included representation to the user.
    1756       </p>
    1757       <p id="rfc.section.8.4.p.2">If the client is sending data, a server implementation using TCP <em class="bcp14">SHOULD</em> be careful to ensure that the client acknowledges receipt of the packet(s) containing the response, before the server closes
    1758          the input connection. If the client continues sending data to the server after the close, the server's TCP stack will send
    1759          a reset packet to the client, which might erase the client's unacknowledged input buffers before they can be read and interpreted
    1760          by the HTTP application.
    1761       </p>
    1762       <div id="rfc.iref.39"></div>
    1763       <div id="rfc.iref.s.19"></div>
    1764       <h3 id="rfc.section.8.4.1"><a href="#rfc.section.8.4.1">8.4.1</a>&nbsp;<a id="status.400" href="#status.400">400 Bad Request</a></h3>
    1765       <p id="rfc.section.8.4.1.p.1">The request could not be understood by the server due to malformed syntax. The client <em class="bcp14">SHOULD NOT</em> repeat the request without modifications.
    1766       </p>
    1767       <div id="rfc.iref.40"></div>
    1768       <div id="rfc.iref.s.20"></div>
    1769       <h3 id="rfc.section.8.4.2"><a href="#rfc.section.8.4.2">8.4.2</a>&nbsp;<a id="status.401" href="#status.401">401 Unauthorized</a></h3>
    1770       <p id="rfc.section.8.4.2.p.1">The request requires user authentication (see <a href="p7-auth.html#status.401" title="401 Unauthorized">Section 3.1</a> of <a href="#Part7" id="rfc.xref.Part7.8"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a>).
    1771       </p>
    1772       <div id="rfc.iref.41"></div>
    1773       <div id="rfc.iref.s.21"></div>
    1774       <h3 id="rfc.section.8.4.3"><a href="#rfc.section.8.4.3">8.4.3</a>&nbsp;<a id="status.402" href="#status.402">402 Payment Required</a></h3>
    1775       <p id="rfc.section.8.4.3.p.1">This code is reserved for future use.</p>
    1776       <div id="rfc.iref.42"></div>
    1777       <div id="rfc.iref.s.22"></div>
    1778       <h3 id="rfc.section.8.4.4"><a href="#rfc.section.8.4.4">8.4.4</a>&nbsp;<a id="status.403" href="#status.403">403 Forbidden</a></h3>
    1779       <p id="rfc.section.8.4.4.p.1">The server understood the request, but refuses to authorize it. Providing different user authentication credentials might
    1780          be successful, but any credentials that were provided in the request are insufficient. The request <em class="bcp14">SHOULD NOT</em> be repeated with the same credentials.
    1781       </p>
    1782       <p id="rfc.section.8.4.4.p.2">If the request method was not HEAD and the server wishes to make public why the request has not been fulfilled, it <em class="bcp14">SHOULD</em> describe the reason for the refusal in the representation. If the server does not wish to make this information available
    1783          to the client, the status code 404 (Not Found) <em class="bcp14">MAY</em> be used instead.
    1784       </p>
    1785       <div id="rfc.iref.43"></div>
    1786       <div id="rfc.iref.s.23"></div>
    1787       <h3 id="rfc.section.8.4.5"><a href="#rfc.section.8.4.5">8.4.5</a>&nbsp;<a id="status.404" href="#status.404">404 Not Found</a></h3>
    1788       <p id="rfc.section.8.4.5.p.1">The server has not found anything matching the effective request URI. No indication is given of whether the condition is temporary
    1789          or permanent. The 410 (Gone) status code <em class="bcp14">SHOULD</em> be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable
    1790          and has no forwarding address. This status code is commonly used when the server does not wish to reveal exactly why the request
    1791          has been refused, or when no other response is applicable.
    1792       </p>
    1793       <div id="rfc.iref.44"></div>
    1794       <div id="rfc.iref.s.24"></div>
    1795       <h3 id="rfc.section.8.4.6"><a href="#rfc.section.8.4.6">8.4.6</a>&nbsp;<a id="status.405" href="#status.405">405 Method Not Allowed</a></h3>
    1796       <p id="rfc.section.8.4.6.p.1">The method specified in the Request-Line is not allowed for the target resource. The response <em class="bcp14">MUST</em> include an Allow header field containing a list of valid methods for the requested resource.
    1797       </p>
    1798       <div id="rfc.iref.45"></div>
    1799       <div id="rfc.iref.s.25"></div>
    1800       <h3 id="rfc.section.8.4.7"><a href="#rfc.section.8.4.7">8.4.7</a>&nbsp;<a id="status.406" href="#status.406">406 Not Acceptable</a></h3>
    1801       <p id="rfc.section.8.4.7.p.1">The resource identified by the request is only capable of generating response representations which have content characteristics
    1802          not acceptable according to the accept header fields sent in the request.
    1803       </p>
    1804       <p id="rfc.section.8.4.7.p.2">Unless it was a HEAD request, the response <em class="bcp14">SHOULD</em> include a representation containing a list of available representation characteristics and location(s) from which the user
    1805          or user agent can choose the one most appropriate. The data format is specified by the media type given in the Content-Type
    1806          header field. Depending upon the format and the capabilities of the user agent, selection of the most appropriate choice <em class="bcp14">MAY</em> be performed automatically. However, this specification does not define any standard for such automatic selection.
    1807       </p>
    1808       <div class="note" id="rfc.section.8.4.7.p.3">
    1809          <p> <b>Note:</b> HTTP/1.1 servers are allowed to return responses which are not acceptable according to the accept header fields sent in the
    1810             request. In some cases, this might even be preferable to sending a 406 response. User agents are encouraged to inspect the
    1811             header fields of an incoming response to determine if it is acceptable.
    1812          </p>
    1813       </div>
    1814       <p id="rfc.section.8.4.7.p.4">If the response could be unacceptable, a user agent <em class="bcp14">SHOULD</em> temporarily stop receipt of more data and query the user for a decision on further actions.
    1815       </p>
    1816       <div id="rfc.iref.46"></div>
    1817       <div id="rfc.iref.s.26"></div>
    1818       <h3 id="rfc.section.8.4.8"><a href="#rfc.section.8.4.8">8.4.8</a>&nbsp;<a id="status.407" href="#status.407">407 Proxy Authentication Required</a></h3>
    1819       <p id="rfc.section.8.4.8.p.1">This code is similar to 401 (Unauthorized), but indicates that the client must first authenticate itself with the proxy (see <a href="p7-auth.html#status.407" title="407 Proxy Authentication Required">Section 3.2</a> of <a href="#Part7" id="rfc.xref.Part7.9"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a>).
    1820       </p>
    1821       <div id="rfc.iref.47"></div>
    1822       <div id="rfc.iref.s.27"></div>
    1823       <h3 id="rfc.section.8.4.9"><a href="#rfc.section.8.4.9">8.4.9</a>&nbsp;<a id="status.408" href="#status.408">408 Request Timeout</a></h3>
    1824       <p id="rfc.section.8.4.9.p.1">The client did not produce a request within the time that the server was prepared to wait. The client <em class="bcp14">MAY</em> repeat the request without modifications at any later time.
    1825       </p>
    1826       <div id="rfc.iref.48"></div>
    1827       <div id="rfc.iref.s.28"></div>
    1828       <h3 id="rfc.section.8.4.10"><a href="#rfc.section.8.4.10">8.4.10</a>&nbsp;<a id="status.409" href="#status.409">409 Conflict</a></h3>
    1829       <p id="rfc.section.8.4.10.p.1">The request could not be completed due to a conflict with the current state of the resource. This code is only allowed in
    1830          situations where it is expected that the user might be able to resolve the conflict and resubmit the request. The response
    1831          body <em class="bcp14">SHOULD</em> include enough information for the user to recognize the source of the conflict. Ideally, the response representation would
    1832          include enough information for the user or user agent to fix the problem; however, that might not be possible and is not required.
    1833       </p>
    1834       <p id="rfc.section.8.4.10.p.2">Conflicts are most likely to occur in response to a PUT request. For example, if versioning were being used and the representation
    1835          being PUT included changes to a resource which conflict with those made by an earlier (third-party) request, the server might
    1836          use the 409 response to indicate that it can't complete the request. In this case, the response representation would likely
    1837          contain a list of the differences between the two versions in a format defined by the response Content-Type.
    1838       </p>
    1839       <div id="rfc.iref.49"></div>
    1840       <div id="rfc.iref.s.29"></div>
    1841       <h3 id="rfc.section.8.4.11"><a href="#rfc.section.8.4.11">8.4.11</a>&nbsp;<a id="status.410" href="#status.410">410 Gone</a></h3>
    1842       <p id="rfc.section.8.4.11.p.1">The target resource is no longer available at the server and no forwarding address is known. This condition is expected to
    1843          be considered permanent. Clients with link editing capabilities <em class="bcp14">SHOULD</em> delete references to the effective request URI after user approval. If the server does not know, or has no facility to determine,
    1844          whether or not the condition is permanent, the status code 404 (Not Found) <em class="bcp14">SHOULD</em> be used instead.
    1845       </p>
    1846       <p id="rfc.section.8.4.11.p.2">The 410 response is primarily intended to assist the task of web maintenance by notifying the recipient that the resource
    1847          is intentionally unavailable and that the server owners desire that remote links to that resource be removed. Such an event
    1848          is common for limited-time, promotional services and for resources belonging to individuals no longer working at the server's
    1849          site. It is not necessary to mark all permanently unavailable resources as "gone" or to keep the mark for any length of time
    1850          — that is left to the discretion of the server owner.
    1851       </p>
    1852       <p id="rfc.section.8.4.11.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.18"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 410 responses.
    1853       </p>
    1854       <div id="rfc.iref.50"></div>
    1855       <div id="rfc.iref.s.30"></div>
    1856       <h3 id="rfc.section.8.4.12"><a href="#rfc.section.8.4.12">8.4.12</a>&nbsp;<a id="status.411" href="#status.411">411 Length Required</a></h3>
    1857       <p id="rfc.section.8.4.12.p.1">The server refuses to accept the request without a defined Content-Length. The client <em class="bcp14">MAY</em> repeat the request if it adds a valid Content-Length header field containing the length of the message-body in the request
    1858          message.
    1859       </p>
    1860       <div id="rfc.iref.51"></div>
    1861       <div id="rfc.iref.s.31"></div>
    1862       <h3 id="rfc.section.8.4.13"><a href="#rfc.section.8.4.13">8.4.13</a>&nbsp;<a id="status.412" href="#status.412">412 Precondition Failed</a></h3>
    1863       <p id="rfc.section.8.4.13.p.1">The precondition given in one or more of the header fields evaluated to false when it was tested on the server, as defined
    1864          in <a href="p4-conditional.html#status.412" title="412 Precondition Failed">Section 4.2</a> of <a href="#Part4" id="rfc.xref.Part4.11"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>.
    1865       </p>
    1866       <div id="rfc.iref.52"></div>
    1867       <div id="rfc.iref.s.32"></div>
    1868       <h3 id="rfc.section.8.4.14"><a href="#rfc.section.8.4.14">8.4.14</a>&nbsp;<a id="status.413" href="#status.413">413 Request Representation Too Large</a></h3>
    1869       <p id="rfc.section.8.4.14.p.1">The server is refusing to process a request because the request representation is larger than the server is willing or able
    1870          to process. The server <em class="bcp14">MAY</em> close the connection to prevent the client from continuing the request.
    1871       </p>
    1872       <p id="rfc.section.8.4.14.p.2">If the condition is temporary, the server <em class="bcp14">SHOULD</em> include a Retry-After header field to indicate that it is temporary and after what time the client <em class="bcp14">MAY</em> try again.
    1873       </p>
    1874       <div id="rfc.iref.53"></div>
    1875       <div id="rfc.iref.s.33"></div>
    1876       <h3 id="rfc.section.8.4.15"><a href="#rfc.section.8.4.15">8.4.15</a>&nbsp;<a id="status.414" href="#status.414">414 URI Too Long</a></h3>
    1877       <p id="rfc.section.8.4.15.p.1">The server is refusing to service the request because the effective request URI is longer than the server is willing to interpret.
    1878          This rare condition is only likely to occur when a client has improperly converted a POST request to a GET request with long
    1879          query information, when the client has descended into a URI "black hole" of redirection (e.g., a redirected URI prefix that
    1880          points to a suffix of itself), or when the server is under attack by a client attempting to exploit security holes present
    1881          in some servers using fixed-length buffers for reading or manipulating the effective request URI.
    1882       </p>
    1883       <div id="rfc.iref.54"></div>
    1884       <div id="rfc.iref.s.34"></div>
    1885       <h3 id="rfc.section.8.4.16"><a href="#rfc.section.8.4.16">8.4.16</a>&nbsp;<a id="status.415" href="#status.415">415 Unsupported Media Type</a></h3>
    1886       <p id="rfc.section.8.4.16.p.1">The server is refusing to service the request because the request payload is in a format not supported by this request method
    1887          on the target resource.
    1888       </p>
    1889       <div id="rfc.iref.55"></div>
    1890       <div id="rfc.iref.s.35"></div>
    1891       <h3 id="rfc.section.8.4.17"><a href="#rfc.section.8.4.17">8.4.17</a>&nbsp;<a id="status.416" href="#status.416">416 Requested Range Not Satisfiable</a></h3>
    1892       <p id="rfc.section.8.4.17.p.1">The request included a Range header field (<a href="p5-range.html#header.range" title="Range">Section 5.4</a> of <a href="#Part5" id="rfc.xref.Part5.9"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>) and none of the range-specifier values in this field overlap the current extent of the selected resource. See <a href="p5-range.html#status.416" title="416 Requested Range Not Satisfiable">Section 3.2</a> of <a href="#Part5" id="rfc.xref.Part5.10"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>.
    1893       </p>
    1894       <div id="rfc.iref.56"></div>
    1895       <div id="rfc.iref.s.36"></div>
    1896       <h3 id="rfc.section.8.4.18"><a href="#rfc.section.8.4.18">8.4.18</a>&nbsp;<a id="status.417" href="#status.417">417 Expectation Failed</a></h3>
    1897       <p id="rfc.section.8.4.18.p.1">The expectation given in an Expect header field (see <a href="#header.expect" id="rfc.xref.header.expect.2" title="Expect">Section&nbsp;9.2</a>) could not be met by this server, or, if the server is a proxy, the server has unambiguous evidence that the request could
    1898          not be met by the next-hop server.
    1899       </p>
    1900       <div id="rfc.iref.57"></div>
    1901       <div id="rfc.iref.s.37"></div>
    1902       <h3 id="rfc.section.8.4.19"><a href="#rfc.section.8.4.19">8.4.19</a>&nbsp;<a id="status.426" href="#status.426">426 Upgrade Required</a></h3>
    1903       <p id="rfc.section.8.4.19.p.1">The request can not be completed without a prior protocol upgrade. This response <em class="bcp14">MUST</em> include an Upgrade header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 9.8</a> of <a href="#Part1" id="rfc.xref.Part1.29"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) specifying the required protocols.
    1904       </p>
    1905       <div id="rfc.figure.u.7"></div>
    1906       <p>Example:</p>  <pre class="text2">HTTP/1.1 426 Upgrade Required
     1594      <div id="status.codes">
     1595         <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a>&nbsp;<a href="#status.codes">Status Code Definitions</a></h1>
     1596         <p id="rfc.section.8.p.1">Each Status-Code is described below, including any metadata required in the response.</p>
     1597         <div id="status.1xx">
     1598            <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a>&nbsp;<a href="#status.1xx">Informational 1xx</a></h2>
     1599            <p id="rfc.section.8.1.p.1">This class of status code indicates a provisional response, consisting only of the Status-Line and optional header fields,
     1600               and is terminated by an empty line. There are no required header fields for this class of status code. Since HTTP/1.0 did
     1601               not define any 1xx status codes, servers <em class="bcp14">MUST NOT</em> send a 1xx response to an HTTP/1.0 client except under experimental conditions.
     1602            </p>
     1603            <p id="rfc.section.8.1.p.2">A client <em class="bcp14">MUST</em> be prepared to accept one or more 1xx status responses prior to a regular response, even if the client does not expect a 100
     1604               (Continue) status message. Unexpected 1xx status responses <em class="bcp14">MAY</em> be ignored by a user agent.
     1605            </p>
     1606            <p id="rfc.section.8.1.p.3">Proxies <em class="bcp14">MUST</em> forward 1xx responses, unless the connection between the proxy and its client has been closed, or unless the proxy itself
     1607               requested the generation of the 1xx response. (For example, if a proxy adds a "Expect: 100-continue" field when it forwards
     1608               a request, then it need not forward the corresponding 100 (Continue) response(s).)
     1609            </p>
     1610            <div id="status.100">
     1611               <div id="rfc.iref.1.1"></div>
     1612               <div id="rfc.iref.s.2"></div>
     1613               <h3 id="rfc.section.8.1.1"><a href="#rfc.section.8.1.1">8.1.1</a>&nbsp;<a href="#status.100">100 Continue</a></h3>
     1614               <p id="rfc.section.8.1.1.p.1">The client <em class="bcp14">SHOULD</em> continue with its request. This interim response is used to inform the client that the initial part of the request has been
     1615                  received and has not yet been rejected by the server. The client <em class="bcp14">SHOULD</em> continue by sending the remainder of the request or, if the request has already been completed, ignore this response. The
     1616                  server <em class="bcp14">MUST</em> send a final response after the request has been completed. See <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 7.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.25"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> for detailed discussion of the use and handling of this status code.
     1617               </p>
     1618            </div>
     1619            <div id="status.101">
     1620               <div id="rfc.iref.1.2"></div>
     1621               <div id="rfc.iref.s.3"></div>
     1622               <h3 id="rfc.section.8.1.2"><a href="#rfc.section.8.1.2">8.1.2</a>&nbsp;<a href="#status.101">101 Switching Protocols</a></h3>
     1623               <p id="rfc.section.8.1.2.p.1">The server understands and is willing to comply with the client's request, via the Upgrade message header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 9.8</a> of <a href="#Part1" id="rfc.xref.Part1.26"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>), for a change in the application protocol being used on this connection. The server will switch protocols to those defined
     1624                  by the response's Upgrade header field immediately after the empty line which terminates the 101 response.
     1625               </p>
     1626               <p id="rfc.section.8.1.2.p.2">The protocol <em class="bcp14">SHOULD</em> be switched only when it is advantageous to do so. For example, switching to a newer version of HTTP is advantageous over
     1627                  older versions, and switching to a real-time, synchronous protocol might be advantageous when delivering resources that use
     1628                  such features.
     1629               </p>
     1630            </div>
     1631         </div>
     1632         <div id="status.2xx">
     1633            <h2 id="rfc.section.8.2"><a href="#rfc.section.8.2">8.2</a>&nbsp;<a href="#status.2xx">Successful 2xx</a></h2>
     1634            <p id="rfc.section.8.2.p.1">This class of status code indicates that the client's request was successfully received, understood, and accepted.</p>
     1635            <div id="status.200">
     1636               <div id="rfc.iref.2.1"></div>
     1637               <div id="rfc.iref.s.4"></div>
     1638               <h3 id="rfc.section.8.2.1"><a href="#rfc.section.8.2.1">8.2.1</a>&nbsp;<a href="#status.200">200 OK</a></h3>
     1639               <p id="rfc.section.8.2.1.p.1">The request has succeeded. The payload returned with the response is dependent on the method used in the request, for example: </p>
     1640               <dl>
     1641                  <dt>GET</dt>
     1642                  <dd>a representation of the target resource is sent in the response;</dd>
     1643                  <dt>HEAD</dt>
     1644                  <dd>the same representation as GET, except without the message-body;</dd>
     1645                  <dt>POST</dt>
     1646                  <dd>a representation describing or containing the result of the action;</dd>
     1647                  <dt>TRACE</dt>
     1648                  <dd>a representation containing the request message as received by the end server.</dd>
     1649               </dl>
     1650               <p id="rfc.section.8.2.1.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.11"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 200 responses.
     1651               </p>
     1652            </div>
     1653            <div id="status.201">
     1654               <div id="rfc.iref.2.2"></div>
     1655               <div id="rfc.iref.s.5"></div>
     1656               <h3 id="rfc.section.8.2.2"><a href="#rfc.section.8.2.2">8.2.2</a>&nbsp;<a href="#status.201">201 Created</a></h3>
     1657               <p id="rfc.section.8.2.2.p.1">The request has been fulfilled and has resulted in a new resource being created. The newly created resource can be referenced
     1658                  by the URI(s) returned in the payload of the response, with the most specific URI for the resource given by a Location header
     1659                  field. The response <em class="bcp14">SHOULD</em> include a payload containing a list of resource characteristics and location(s) from which the user or user agent can choose
     1660                  the one most appropriate. The payload format is specified by the media type given in the Content-Type header field. The origin
     1661                  server <em class="bcp14">MUST</em> create the resource before returning the 201 status code. If the action cannot be carried out immediately, the server <em class="bcp14">SHOULD</em> respond with 202 (Accepted) response instead.
     1662               </p>
     1663               <p id="rfc.section.8.2.2.p.2">A 201 response <em class="bcp14">MAY</em> contain an ETag response header field indicating the current value of the entity-tag for the representation of the resource
     1664                  just created (see <a href="p4-conditional.html#header.etag" title="ETag">Section 2.2</a> of <a href="#Part4" id="rfc.xref.Part4.9"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>).
     1665               </p>
     1666            </div>
     1667            <div id="status.202">
     1668               <div id="rfc.iref.2.3"></div>
     1669               <div id="rfc.iref.s.6"></div>
     1670               <h3 id="rfc.section.8.2.3"><a href="#rfc.section.8.2.3">8.2.3</a>&nbsp;<a href="#status.202">202 Accepted</a></h3>
     1671               <p id="rfc.section.8.2.3.p.1">The request has been accepted for processing, but the processing has not been completed. The request might or might not eventually
     1672                  be acted upon, as it might be disallowed when processing actually takes place. There is no facility for re-sending a status
     1673                  code from an asynchronous operation such as this.
     1674               </p>
     1675               <p id="rfc.section.8.2.3.p.2">The 202 response is intentionally non-committal. Its purpose is to allow a server to accept a request for some other process
     1676                  (perhaps a batch-oriented process that is only run once per day) without requiring that the user agent's connection to the
     1677                  server persist until the process is completed. The representation returned with this response <em class="bcp14">SHOULD</em> include an indication of the request's current status and either a pointer to a status monitor or some estimate of when the
     1678                  user can expect the request to be fulfilled.
     1679               </p>
     1680            </div>
     1681            <div id="status.203">
     1682               <div id="rfc.iref.2.4"></div>
     1683               <div id="rfc.iref.s.7"></div>
     1684               <h3 id="rfc.section.8.2.4"><a href="#rfc.section.8.2.4">8.2.4</a>&nbsp;<a href="#status.203">203 Non-Authoritative Information</a></h3>
     1685               <p id="rfc.section.8.2.4.p.1">The representation in the response has been transformed or otherwise modified by a transforming proxy (<a href="p1-messaging.html#intermediaries" title="Intermediaries">Section 2.4</a> of <a href="#Part1" id="rfc.xref.Part1.27"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). Note that the behaviour of transforming intermediaries is controlled by the no-transform Cache-Control directive (<a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 3.2</a> of <a href="#Part6" id="rfc.xref.Part6.12"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>).
     1686               </p>
     1687               <p id="rfc.section.8.2.4.p.2">This status code is only appropriate when the response status code would have been 200 (OK) otherwise. When the status code
     1688                  before transformation would have been different, the 214 Transformation Applied warn-code (<a href="p6-cache.html#header.warning" title="Warning">Section 3.6</a> of <a href="#Part6" id="rfc.xref.Part6.13"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) is appropriate.
     1689               </p>
     1690               <p id="rfc.section.8.2.4.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.14"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 203 responses.
     1691               </p>
     1692            </div>
     1693            <div id="status.204">
     1694               <div id="rfc.iref.2.5"></div>
     1695               <div id="rfc.iref.s.8"></div>
     1696               <h3 id="rfc.section.8.2.5"><a href="#rfc.section.8.2.5">8.2.5</a>&nbsp;<a href="#status.204">204 No Content</a></h3>
     1697               <p id="rfc.section.8.2.5.p.1">The 204 (No Content) status code indicates that the server has successfully fulfilled the request and that there is no additional
     1698                  content to return in the response payload body. Metadata in the response header fields refer to the target resource and its
     1699                  current representation after the requested action.
     1700               </p>
     1701               <p id="rfc.section.8.2.5.p.2">For example, if a 204 status code is received in response to a PUT request and the response contains an ETag header field,
     1702                  then the PUT was successful and the ETag field-value contains the entity-tag for the new representation of that target resource.
     1703               </p>
     1704               <p id="rfc.section.8.2.5.p.3">The 204 response allows a server to indicate that the action has been successfully applied to the target resource while implying
     1705                  that the user agent <em class="bcp14">SHOULD NOT</em> traverse away from its current "document view" (if any). The server assumes that the user agent will provide some indication
     1706                  of the success to its user, in accord with its own interface, and apply any new or updated metadata in the response to the
     1707                  active representation.
     1708               </p>
     1709               <p id="rfc.section.8.2.5.p.4">For example, a 204 status code is commonly used with document editing interfaces corresponding to a "save" action, such that
     1710                  the document being saved remains available to the user for editing. It is also frequently used with interfaces that expect
     1711                  automated data transfers to be prevalent, such as within distributed version control systems.
     1712               </p>
     1713               <p id="rfc.section.8.2.5.p.5">The 204 response <em class="bcp14">MUST NOT</em> include a message-body, and thus is always terminated by the first empty line after the header fields.
     1714               </p>
     1715            </div>
     1716            <div id="status.205">
     1717               <div id="rfc.iref.2.6"></div>
     1718               <div id="rfc.iref.s.9"></div>
     1719               <h3 id="rfc.section.8.2.6"><a href="#rfc.section.8.2.6">8.2.6</a>&nbsp;<a href="#status.205">205 Reset Content</a></h3>
     1720               <p id="rfc.section.8.2.6.p.1">The server has fulfilled the request and the user agent <em class="bcp14">SHOULD</em> reset the document view which caused the request to be sent. This response is primarily intended to allow input for actions
     1721                  to take place via user input, followed by a clearing of the form in which the input is given so that the user can easily initiate
     1722                  another input action.
     1723               </p>
     1724               <p id="rfc.section.8.2.6.p.2">The message-body included with the response <em class="bcp14">MUST</em> be empty. Note that receivers still need to parse the response according to the algorithm defined in <a href="p1-messaging.html#message.body" title="Message Body">Section 3.3</a> of <a href="#Part1" id="rfc.xref.Part1.28"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>.
     1725               </p>
     1726            </div>
     1727            <div id="status.206">
     1728               <div id="rfc.iref.2.7"></div>
     1729               <div id="rfc.iref.s.10"></div>
     1730               <h3 id="rfc.section.8.2.7"><a href="#rfc.section.8.2.7">8.2.7</a>&nbsp;<a href="#status.206">206 Partial Content</a></h3>
     1731               <p id="rfc.section.8.2.7.p.1">The server has fulfilled the partial GET request for the resource and the enclosed payload is a partial representation as
     1732                  defined in <a href="p5-range.html#status.206" title="206 Partial Content">Section 3.1</a> of <a href="#Part5" id="rfc.xref.Part5.8"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>.
     1733               </p>
     1734               <p id="rfc.section.8.2.7.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.15"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 206 responses.
     1735               </p>
     1736            </div>
     1737         </div>
     1738         <div id="status.3xx">
     1739            <h2 id="rfc.section.8.3"><a href="#rfc.section.8.3">8.3</a>&nbsp;<a href="#status.3xx">Redirection 3xx</a></h2>
     1740            <p id="rfc.section.8.3.p.1">This class of status code indicates that further action needs to be taken by the user agent in order to fulfill the request.
     1741               The action required <em class="bcp14">MAY</em> be carried out by the user agent without interaction with the user if and only if the method used in the second request is
     1742               known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>. A client <em class="bcp14">SHOULD</em> detect infinite redirection loops, since such loops generate network traffic for each redirection.
     1743            </p>
     1744            <div class="note" id="rfc.section.8.3.p.2">
     1745               <p><b>Note:</b> An earlier version of this specification recommended a maximum of five redirections (<a href="#RFC2068" id="rfc.xref.RFC2068.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, <a href="https://tools.ietf.org/html/rfc2068#section-10.3">Section 10.3</a>). Content developers need to be aware that some clients might implement such a fixed limitation.
     1746               </p>
     1747            </div>
     1748            <div id="status.300">
     1749               <div id="rfc.iref.3.1"></div>
     1750               <div id="rfc.iref.s.11"></div>
     1751               <h3 id="rfc.section.8.3.1"><a href="#rfc.section.8.3.1">8.3.1</a>&nbsp;<a href="#status.300">300 Multiple Choices</a></h3>
     1752               <p id="rfc.section.8.3.1.p.1">The target resource has more than one representation, each with its own specific location, and agent-driven negotiation information
     1753                  (<a href="p3-payload.html#content.negotiation" title="Content Negotiation">Section 5</a> of <a href="#Part3" id="rfc.xref.Part3.7"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) is being provided so that the user (or user agent) can select a preferred representation by redirecting its request to that
     1754                  location.
     1755               </p>
     1756               <p id="rfc.section.8.3.1.p.2">Unless it was a HEAD request, the response <em class="bcp14">SHOULD</em> include a representation containing a list of representation metadata and location(s) from which the user or user agent can
     1757                  choose the one most appropriate. The data format is specified by the media type given in the Content-Type header field. Depending
     1758                  upon the format and the capabilities of the user agent, selection of the most appropriate choice <em class="bcp14">MAY</em> be performed automatically. However, this specification does not define any standard for such automatic selection.
     1759               </p>
     1760               <p id="rfc.section.8.3.1.p.3">If the server has a preferred choice of representation, it <em class="bcp14">SHOULD</em> include the specific URI for that representation in the Location field; user agents <em class="bcp14">MAY</em> use the Location field value for automatic redirection.
     1761               </p>
     1762               <p id="rfc.section.8.3.1.p.4">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.16"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 300 responses.
     1763               </p>
     1764            </div>
     1765            <div id="status.301">
     1766               <div id="rfc.iref.3.2"></div>
     1767               <div id="rfc.iref.s.12"></div>
     1768               <h3 id="rfc.section.8.3.2"><a href="#rfc.section.8.3.2">8.3.2</a>&nbsp;<a href="#status.301">301 Moved Permanently</a></h3>
     1769               <p id="rfc.section.8.3.2.p.1">The target resource has been assigned a new permanent URI and any future references to this resource <em class="bcp14">SHOULD</em> use one of the returned URIs. Clients with link editing capabilities ought to automatically re-link references to the effective
     1770                  request URI to one or more of the new references returned by the server, where possible.
     1771               </p>
     1772               <p id="rfc.section.8.3.2.p.2">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.17"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 301 responses.
     1773               </p>
     1774               <p id="rfc.section.8.3.2.p.3">The new permanent URI <em class="bcp14">SHOULD</em> be given by the Location field in the response. Unless the request method was HEAD, the representation of the response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the new URI(s).
     1775               </p>
     1776               <p id="rfc.section.8.3.2.p.4">If the 301 status code is received in response to a request method that is known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>, then the request <em class="bcp14">MAY</em> be automatically redirected by the user agent without confirmation. Otherwise, the user agent <em class="bcp14">MUST NOT</em> automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which
     1777                  the request was issued.
     1778               </p>
     1779               <div class="note" id="rfc.section.8.3.2.p.5">
     1780                  <p><b>Note:</b> When automatically redirecting a POST request after receiving a 301 status code, some existing HTTP/1.0 user agents will erroneously
     1781                     change it into a GET request.
     1782                  </p>
     1783               </div>
     1784            </div>
     1785            <div id="status.302">
     1786               <div id="rfc.iref.3.3"></div>
     1787               <div id="rfc.iref.s.13"></div>
     1788               <h3 id="rfc.section.8.3.3"><a href="#rfc.section.8.3.3">8.3.3</a>&nbsp;<a href="#status.302">302 Found</a></h3>
     1789               <p id="rfc.section.8.3.3.p.1">The target resource resides temporarily under a different URI. Since the redirection might be altered on occasion, the client <em class="bcp14">SHOULD</em> continue to use the effective request URI for future requests.
     1790               </p>
     1791               <p id="rfc.section.8.3.3.p.2">The temporary URI <em class="bcp14">SHOULD</em> be given by the Location field in the response. Unless the request method was HEAD, the representation of the response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the new URI(s).
     1792               </p>
     1793               <p id="rfc.section.8.3.3.p.3">If the 302 status code is received in response to a request method that is known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>, then the request <em class="bcp14">MAY</em> be automatically redirected by the user agent without confirmation. Otherwise, the user agent <em class="bcp14">MUST NOT</em> automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which
     1794                  the request was issued.
     1795               </p>
     1796               <div class="note" id="rfc.section.8.3.3.p.4">
     1797                  <p><b>Note:</b> HTTP/1.0 (<a href="#RFC1945" id="rfc.xref.RFC1945.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.0">[RFC1945]</cite></a>, <a href="https://tools.ietf.org/html/rfc1945#section-9.3">Section 9.3</a>) and the first version of HTTP/1.1 (<a href="#RFC2068" id="rfc.xref.RFC2068.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, <a href="https://tools.ietf.org/html/rfc2068#section-10.3.3">Section 10.3.3</a>) specify that the client is not allowed to change the method on the redirected request. However, most existing user agent
     1798                     implementations treat 302 as if it were a 303 response, performing a GET on the Location field-value regardless of the original
     1799                     request method. Therefore, a previous version of this specification (<a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>, <a href="https://tools.ietf.org/html/rfc2616#section-10.3.3">Section 10.3.3</a>) has added the status codes <a href="#status.303" id="rfc.xref.status.303.2">303</a> and <a href="#status.307" id="rfc.xref.status.307.2">307</a> for servers that wish to make unambiguously clear which kind of reaction is expected of the client.
     1800                  </p>
     1801               </div>
     1802            </div>
     1803            <div id="status.303">
     1804               <div id="rfc.iref.3.4"></div>
     1805               <div id="rfc.iref.s.14"></div>
     1806               <h3 id="rfc.section.8.3.4"><a href="#rfc.section.8.3.4">8.3.4</a>&nbsp;<a href="#status.303">303 See Other</a></h3>
     1807               <p id="rfc.section.8.3.4.p.1">The server directs the user agent to a different resource, indicated by a URI in the Location header field, that provides
     1808                  an indirect response to the original request. The user agent <em class="bcp14">MAY</em> perform a GET request on the URI in the Location field in order to obtain a representation corresponding to the response,
     1809                  be redirected again, or end with an error status. The Location URI is not a substitute reference for the effective request
     1810                  URI.
     1811               </p>
     1812               <p id="rfc.section.8.3.4.p.2">The 303 status code is generally applicable to any HTTP method. It is primarily used to allow the output of a POST action
     1813                  to redirect the user agent to a selected resource, since doing so provides the information corresponding to the POST response
     1814                  in a form that can be separately identified, bookmarked, and cached independent of the original request.
     1815               </p>
     1816               <p id="rfc.section.8.3.4.p.3">A 303 response to a GET request indicates that the requested resource does not have a representation of its own that can be
     1817                  transferred by the server over HTTP. The Location URI indicates a resource that is descriptive of the target resource, such
     1818                  that the follow-on representation might be useful to recipients without implying that it adequately represents the target
     1819                  resource. Note that answers to the questions of what can be represented, what representations are adequate, and what might
     1820                  be a useful description are outside the scope of HTTP and thus entirely determined by the URI owner(s).
     1821               </p>
     1822               <p id="rfc.section.8.3.4.p.4">Except for responses to a HEAD request, the representation of a 303 response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the Location URI.
     1823               </p>
     1824            </div>
     1825            <div id="status.304">
     1826               <div id="rfc.iref.3.5"></div>
     1827               <div id="rfc.iref.s.15"></div>
     1828               <h3 id="rfc.section.8.3.5"><a href="#rfc.section.8.3.5">8.3.5</a>&nbsp;<a href="#status.304">304 Not Modified</a></h3>
     1829               <p id="rfc.section.8.3.5.p.1">The response to the request has not been modified since the conditions indicated by the client's conditional GET request,
     1830                  as defined in <a href="p4-conditional.html#status.304" title="304 Not Modified">Section 4.1</a> of <a href="#Part4" id="rfc.xref.Part4.10"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>.
     1831               </p>
     1832            </div>
     1833            <div id="status.305">
     1834               <div id="rfc.iref.3.6"></div>
     1835               <div id="rfc.iref.s.16"></div>
     1836               <h3 id="rfc.section.8.3.6"><a href="#rfc.section.8.3.6">8.3.6</a>&nbsp;<a href="#status.305">305 Use Proxy</a></h3>
     1837               <p id="rfc.section.8.3.6.p.1">The 305 status code was defined in a previous version of this specification (see <a href="#changes.from.rfc.2616" title="Changes from RFC 2616">Appendix&nbsp;A</a>), and is now deprecated.
     1838               </p>
     1839            </div>
     1840            <div id="status.306">
     1841               <div id="rfc.iref.3.7"></div>
     1842               <div id="rfc.iref.s.17"></div>
     1843               <h3 id="rfc.section.8.3.7"><a href="#rfc.section.8.3.7">8.3.7</a>&nbsp;<a href="#status.306">306 (Unused)</a></h3>
     1844               <p id="rfc.section.8.3.7.p.1">The 306 status code was used in a previous version of the specification, is no longer used, and the code is reserved.</p>
     1845            </div>
     1846            <div id="status.307">
     1847               <div id="rfc.iref.3.8"></div>
     1848               <div id="rfc.iref.s.18"></div>
     1849               <h3 id="rfc.section.8.3.8"><a href="#rfc.section.8.3.8">8.3.8</a>&nbsp;<a href="#status.307">307 Temporary Redirect</a></h3>
     1850               <p id="rfc.section.8.3.8.p.1">The target resource resides temporarily under a different URI. Since the redirection can change over time, the client <em class="bcp14">SHOULD</em> continue to use the effective request URI for future requests.
     1851               </p>
     1852               <p id="rfc.section.8.3.8.p.2">The temporary URI <em class="bcp14">SHOULD</em> be given by the Location field in the response. Unless the request method was HEAD, the representation of the response <em class="bcp14">SHOULD</em> contain a short hypertext note with a hyperlink to the new URI(s), since many pre-HTTP/1.1 user agents do not understand the
     1853                  307 status code. Therefore, the note <em class="bcp14">SHOULD</em> contain the information necessary for a user to repeat the original request on the new URI.
     1854               </p>
     1855               <p id="rfc.section.8.3.8.p.3">If the 307 status code is received in response to a request method that is known to be "safe", as defined in <a href="#safe.methods" title="Safe Methods">Section&nbsp;7.1.1</a>, then the request <em class="bcp14">MAY</em> be automatically redirected by the user agent without confirmation. Otherwise, the user agent <em class="bcp14">MUST NOT</em> automatically redirect the request unless it can be confirmed by the user, since this might change the conditions under which
     1856                  the request was issued.
     1857               </p>
     1858            </div>
     1859         </div>
     1860         <div id="status.4xx">
     1861            <h2 id="rfc.section.8.4"><a href="#rfc.section.8.4">8.4</a>&nbsp;<a href="#status.4xx">Client Error 4xx</a></h2>
     1862            <p id="rfc.section.8.4.p.1">The 4xx class of status code is intended for cases in which the client seems to have erred. Except when responding to a HEAD
     1863               request, the server <em class="bcp14">SHOULD</em> include a representation containing an explanation of the error situation, and whether it is a temporary or permanent condition.
     1864               These status codes are applicable to any request method. User agents <em class="bcp14">SHOULD</em> display any included representation to the user.
     1865            </p>
     1866            <p id="rfc.section.8.4.p.2">If the client is sending data, a server implementation using TCP <em class="bcp14">SHOULD</em> be careful to ensure that the client acknowledges receipt of the packet(s) containing the response, before the server closes
     1867               the input connection. If the client continues sending data to the server after the close, the server's TCP stack will send
     1868               a reset packet to the client, which might erase the client's unacknowledged input buffers before they can be read and interpreted
     1869               by the HTTP application.
     1870            </p>
     1871            <div id="status.400">
     1872               <div id="rfc.iref.4.1"></div>
     1873               <div id="rfc.iref.s.19"></div>
     1874               <h3 id="rfc.section.8.4.1"><a href="#rfc.section.8.4.1">8.4.1</a>&nbsp;<a href="#status.400">400 Bad Request</a></h3>
     1875               <p id="rfc.section.8.4.1.p.1">The request could not be understood by the server due to malformed syntax. The client <em class="bcp14">SHOULD NOT</em> repeat the request without modifications.
     1876               </p>
     1877            </div>
     1878            <div id="status.401">
     1879               <div id="rfc.iref.4.2"></div>
     1880               <div id="rfc.iref.s.20"></div>
     1881               <h3 id="rfc.section.8.4.2"><a href="#rfc.section.8.4.2">8.4.2</a>&nbsp;<a href="#status.401">401 Unauthorized</a></h3>
     1882               <p id="rfc.section.8.4.2.p.1">The request requires user authentication (see <a href="p7-auth.html#status.401" title="401 Unauthorized">Section 3.1</a> of <a href="#Part7" id="rfc.xref.Part7.8"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a>).
     1883               </p>
     1884            </div>
     1885            <div id="status.402">
     1886               <div id="rfc.iref.4.3"></div>
     1887               <div id="rfc.iref.s.21"></div>
     1888               <h3 id="rfc.section.8.4.3"><a href="#rfc.section.8.4.3">8.4.3</a>&nbsp;<a href="#status.402">402 Payment Required</a></h3>
     1889               <p id="rfc.section.8.4.3.p.1">This code is reserved for future use.</p>
     1890            </div>
     1891            <div id="status.403">
     1892               <div id="rfc.iref.4.4"></div>
     1893               <div id="rfc.iref.s.22"></div>
     1894               <h3 id="rfc.section.8.4.4"><a href="#rfc.section.8.4.4">8.4.4</a>&nbsp;<a href="#status.403">403 Forbidden</a></h3>
     1895               <p id="rfc.section.8.4.4.p.1">The server understood the request, but refuses to authorize it. Providing different user authentication credentials might
     1896                  be successful, but any credentials that were provided in the request are insufficient. The request <em class="bcp14">SHOULD NOT</em> be repeated with the same credentials.
     1897               </p>
     1898               <p id="rfc.section.8.4.4.p.2">If the request method was not HEAD and the server wishes to make public why the request has not been fulfilled, it <em class="bcp14">SHOULD</em> describe the reason for the refusal in the representation. If the server does not wish to make this information available
     1899                  to the client, the status code 404 (Not Found) <em class="bcp14">MAY</em> be used instead.
     1900               </p>
     1901            </div>
     1902            <div id="status.404">
     1903               <div id="rfc.iref.4.5"></div>
     1904               <div id="rfc.iref.s.23"></div>
     1905               <h3 id="rfc.section.8.4.5"><a href="#rfc.section.8.4.5">8.4.5</a>&nbsp;<a href="#status.404">404 Not Found</a></h3>
     1906               <p id="rfc.section.8.4.5.p.1">The server has not found anything matching the effective request URI. No indication is given of whether the condition is temporary
     1907                  or permanent. The 410 (Gone) status code <em class="bcp14">SHOULD</em> be used if the server knows, through some internally configurable mechanism, that an old resource is permanently unavailable
     1908                  and has no forwarding address. This status code is commonly used when the server does not wish to reveal exactly why the request
     1909                  has been refused, or when no other response is applicable.
     1910               </p>
     1911            </div>
     1912            <div id="status.405">
     1913               <div id="rfc.iref.4.6"></div>
     1914               <div id="rfc.iref.s.24"></div>
     1915               <h3 id="rfc.section.8.4.6"><a href="#rfc.section.8.4.6">8.4.6</a>&nbsp;<a href="#status.405">405 Method Not Allowed</a></h3>
     1916               <p id="rfc.section.8.4.6.p.1">The method specified in the Request-Line is not allowed for the target resource. The response <em class="bcp14">MUST</em> include an Allow header field containing a list of valid methods for the requested resource.
     1917               </p>
     1918            </div>
     1919            <div id="status.406">
     1920               <div id="rfc.iref.4.7"></div>
     1921               <div id="rfc.iref.s.25"></div>
     1922               <h3 id="rfc.section.8.4.7"><a href="#rfc.section.8.4.7">8.4.7</a>&nbsp;<a href="#status.406">406 Not Acceptable</a></h3>
     1923               <p id="rfc.section.8.4.7.p.1">The resource identified by the request is only capable of generating response representations which have content characteristics
     1924                  not acceptable according to the accept header fields sent in the request.
     1925               </p>
     1926               <p id="rfc.section.8.4.7.p.2">Unless it was a HEAD request, the response <em class="bcp14">SHOULD</em> include a representation containing a list of available representation characteristics and location(s) from which the user
     1927                  or user agent can choose the one most appropriate. The data format is specified by the media type given in the Content-Type
     1928                  header field. Depending upon the format and the capabilities of the user agent, selection of the most appropriate choice <em class="bcp14">MAY</em> be performed automatically. However, this specification does not define any standard for such automatic selection.
     1929               </p>
     1930               <div class="note" id="rfc.section.8.4.7.p.3">
     1931                  <p><b>Note:</b> HTTP/1.1 servers are allowed to return responses which are not acceptable according to the accept header fields sent in the
     1932                     request. In some cases, this might even be preferable to sending a 406 response. User agents are encouraged to inspect the
     1933                     header fields of an incoming response to determine if it is acceptable.
     1934                  </p>
     1935               </div>
     1936               <p id="rfc.section.8.4.7.p.4">If the response could be unacceptable, a user agent <em class="bcp14">SHOULD</em> temporarily stop receipt of more data and query the user for a decision on further actions.
     1937               </p>
     1938            </div>
     1939            <div id="status.407">
     1940               <div id="rfc.iref.4.8"></div>
     1941               <div id="rfc.iref.s.26"></div>
     1942               <h3 id="rfc.section.8.4.8"><a href="#rfc.section.8.4.8">8.4.8</a>&nbsp;<a href="#status.407">407 Proxy Authentication Required</a></h3>
     1943               <p id="rfc.section.8.4.8.p.1">This code is similar to 401 (Unauthorized), but indicates that the client must first authenticate itself with the proxy (see <a href="p7-auth.html#status.407" title="407 Proxy Authentication Required">Section 3.2</a> of <a href="#Part7" id="rfc.xref.Part7.9"><cite title="HTTP/1.1, part 7: Authentication">[Part7]</cite></a>).
     1944               </p>
     1945            </div>
     1946            <div id="status.408">
     1947               <div id="rfc.iref.4.9"></div>
     1948               <div id="rfc.iref.s.27"></div>
     1949               <h3 id="rfc.section.8.4.9"><a href="#rfc.section.8.4.9">8.4.9</a>&nbsp;<a href="#status.408">408 Request Timeout</a></h3>
     1950               <p id="rfc.section.8.4.9.p.1">The client did not produce a request within the time that the server was prepared to wait. The client <em class="bcp14">MAY</em> repeat the request without modifications at any later time.
     1951               </p>
     1952            </div>
     1953            <div id="status.409">
     1954               <div id="rfc.iref.4.10"></div>
     1955               <div id="rfc.iref.s.28"></div>
     1956               <h3 id="rfc.section.8.4.10"><a href="#rfc.section.8.4.10">8.4.10</a>&nbsp;<a href="#status.409">409 Conflict</a></h3>
     1957               <p id="rfc.section.8.4.10.p.1">The request could not be completed due to a conflict with the current state of the resource. This code is only allowed in
     1958                  situations where it is expected that the user might be able to resolve the conflict and resubmit the request. The response
     1959                  body <em class="bcp14">SHOULD</em> include enough information for the user to recognize the source of the conflict. Ideally, the response representation would
     1960                  include enough information for the user or user agent to fix the problem; however, that might not be possible and is not required.
     1961               </p>
     1962               <p id="rfc.section.8.4.10.p.2">Conflicts are most likely to occur in response to a PUT request. For example, if versioning were being used and the representation
     1963                  being PUT included changes to a resource which conflict with those made by an earlier (third-party) request, the server might
     1964                  use the 409 response to indicate that it can't complete the request. In this case, the response representation would likely
     1965                  contain a list of the differences between the two versions in a format defined by the response Content-Type.
     1966               </p>
     1967            </div>
     1968            <div id="status.410">
     1969               <div id="rfc.iref.4.11"></div>
     1970               <div id="rfc.iref.s.29"></div>
     1971               <h3 id="rfc.section.8.4.11"><a href="#rfc.section.8.4.11">8.4.11</a>&nbsp;<a href="#status.410">410 Gone</a></h3>
     1972               <p id="rfc.section.8.4.11.p.1">The target resource is no longer available at the server and no forwarding address is known. This condition is expected to
     1973                  be considered permanent. Clients with link editing capabilities <em class="bcp14">SHOULD</em> delete references to the effective request URI after user approval. If the server does not know, or has no facility to determine,
     1974                  whether or not the condition is permanent, the status code 404 (Not Found) <em class="bcp14">SHOULD</em> be used instead.
     1975               </p>
     1976               <p id="rfc.section.8.4.11.p.2">The 410 response is primarily intended to assist the task of web maintenance by notifying the recipient that the resource
     1977                  is intentionally unavailable and that the server owners desire that remote links to that resource be removed. Such an event
     1978                  is common for limited-time, promotional services and for resources belonging to individuals no longer working at the server's
     1979                  site. It is not necessary to mark all permanently unavailable resources as "gone" or to keep the mark for any length of time
     1980                  — that is left to the discretion of the server owner.
     1981               </p>
     1982               <p id="rfc.section.8.4.11.p.3">Caches <em class="bcp14">MAY</em> use a heuristic (see <a href="p6-cache.html#heuristic.freshness" title="Calculating Heuristic Freshness">Section 2.3.1.1</a> of <a href="#Part6" id="rfc.xref.Part6.18"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) to determine freshness for 410 responses.
     1983               </p>
     1984            </div>
     1985            <div id="status.411">
     1986               <div id="rfc.iref.4.12"></div>
     1987               <div id="rfc.iref.s.30"></div>
     1988               <h3 id="rfc.section.8.4.12"><a href="#rfc.section.8.4.12">8.4.12</a>&nbsp;<a href="#status.411">411 Length Required</a></h3>
     1989               <p id="rfc.section.8.4.12.p.1">The server refuses to accept the request without a defined Content-Length. The client <em class="bcp14">MAY</em> repeat the request if it adds a valid Content-Length header field containing the length of the message-body in the request
     1990                  message.
     1991               </p>
     1992            </div>
     1993            <div id="status.412">
     1994               <div id="rfc.iref.4.13"></div>
     1995               <div id="rfc.iref.s.31"></div>
     1996               <h3 id="rfc.section.8.4.13"><a href="#rfc.section.8.4.13">8.4.13</a>&nbsp;<a href="#status.412">412 Precondition Failed</a></h3>
     1997               <p id="rfc.section.8.4.13.p.1">The precondition given in one or more of the header fields evaluated to false when it was tested on the server, as defined
     1998                  in <a href="p4-conditional.html#status.412" title="412 Precondition Failed">Section 4.2</a> of <a href="#Part4" id="rfc.xref.Part4.11"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>.
     1999               </p>
     2000            </div>
     2001            <div id="status.413">
     2002               <div id="rfc.iref.4.14"></div>
     2003               <div id="rfc.iref.s.32"></div>
     2004               <h3 id="rfc.section.8.4.14"><a href="#rfc.section.8.4.14">8.4.14</a>&nbsp;<a href="#status.413">413 Request Representation Too Large</a></h3>
     2005               <p id="rfc.section.8.4.14.p.1">The server is refusing to process a request because the request representation is larger than the server is willing or able
     2006                  to process. The server <em class="bcp14">MAY</em> close the connection to prevent the client from continuing the request.
     2007               </p>
     2008               <p id="rfc.section.8.4.14.p.2">If the condition is temporary, the server <em class="bcp14">SHOULD</em> include a Retry-After header field to indicate that it is temporary and after what time the client <em class="bcp14">MAY</em> try again.
     2009               </p>
     2010            </div>
     2011            <div id="status.414">
     2012               <div id="rfc.iref.4.15"></div>
     2013               <div id="rfc.iref.s.33"></div>
     2014               <h3 id="rfc.section.8.4.15"><a href="#rfc.section.8.4.15">8.4.15</a>&nbsp;<a href="#status.414">414 URI Too Long</a></h3>
     2015               <p id="rfc.section.8.4.15.p.1">The server is refusing to service the request because the effective request URI is longer than the server is willing to interpret.
     2016                  This rare condition is only likely to occur when a client has improperly converted a POST request to a GET request with long
     2017                  query information, when the client has descended into a URI "black hole" of redirection (e.g., a redirected URI prefix that
     2018                  points to a suffix of itself), or when the server is under attack by a client attempting to exploit security holes present
     2019                  in some servers using fixed-length buffers for reading or manipulating the effective request URI.
     2020               </p>
     2021            </div>
     2022            <div id="status.415">
     2023               <div id="rfc.iref.4.16"></div>
     2024               <div id="rfc.iref.s.34"></div>
     2025               <h3 id="rfc.section.8.4.16"><a href="#rfc.section.8.4.16">8.4.16</a>&nbsp;<a href="#status.415">415 Unsupported Media Type</a></h3>
     2026               <p id="rfc.section.8.4.16.p.1">The server is refusing to service the request because the request payload is in a format not supported by this request method
     2027                  on the target resource.
     2028               </p>
     2029            </div>
     2030            <div id="status.416">
     2031               <div id="rfc.iref.4.17"></div>
     2032               <div id="rfc.iref.s.35"></div>
     2033               <h3 id="rfc.section.8.4.17"><a href="#rfc.section.8.4.17">8.4.17</a>&nbsp;<a href="#status.416">416 Requested Range Not Satisfiable</a></h3>
     2034               <p id="rfc.section.8.4.17.p.1">The request included a Range header field (<a href="p5-range.html#header.range" title="Range">Section 5.4</a> of <a href="#Part5" id="rfc.xref.Part5.9"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>) and none of the range-specifier values in this field overlap the current extent of the selected resource. See <a href="p5-range.html#status.416" title="416 Requested Range Not Satisfiable">Section 3.2</a> of <a href="#Part5" id="rfc.xref.Part5.10"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>.
     2035               </p>
     2036            </div>
     2037            <div id="status.417">
     2038               <div id="rfc.iref.4.18"></div>
     2039               <div id="rfc.iref.s.36"></div>
     2040               <h3 id="rfc.section.8.4.18"><a href="#rfc.section.8.4.18">8.4.18</a>&nbsp;<a href="#status.417">417 Expectation Failed</a></h3>
     2041               <p id="rfc.section.8.4.18.p.1">The expectation given in an Expect header field (see <a href="#header.expect" id="rfc.xref.header.expect.2" title="Expect">Section&nbsp;9.2</a>) could not be met by this server, or, if the server is a proxy, the server has unambiguous evidence that the request could
     2042                  not be met by the next-hop server.
     2043               </p>
     2044            </div>
     2045            <div id="status.426">
     2046               <div id="rfc.iref.4.19"></div>
     2047               <div id="rfc.iref.s.37"></div>
     2048               <h3 id="rfc.section.8.4.19"><a href="#rfc.section.8.4.19">8.4.19</a>&nbsp;<a href="#status.426">426 Upgrade Required</a></h3>
     2049               <p id="rfc.section.8.4.19.p.1">The request can not be completed without a prior protocol upgrade. This response <em class="bcp14">MUST</em> include an Upgrade header field (<a href="p1-messaging.html#header.upgrade" title="Upgrade">Section 9.8</a> of <a href="#Part1" id="rfc.xref.Part1.29"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) specifying the required protocols.
     2050               </p>
     2051               <div id="rfc.figure.u.7"></div>
     2052               <p>Example:</p><pre class="text2">HTTP/1.1 426 Upgrade Required
    19072053Upgrade: HTTP/2.0
    19082054Connection: Upgrade
    19092055
    19102056</pre><p id="rfc.section.8.4.19.p.3">The server <em class="bcp14">SHOULD</em> include a message body in the 426 response which indicates in human readable form the reason for the error and describes any
    1911          alternative courses which may be available to the user.
    1912       </p>
    1913       <h2 id="rfc.section.8.5"><a href="#rfc.section.8.5">8.5</a>&nbsp;<a id="status.5xx" href="#status.5xx">Server Error 5xx</a></h2>
    1914       <p id="rfc.section.8.5.p.1">Response status codes beginning with the digit "5" indicate cases in which the server is aware that it has erred or is incapable
    1915          of performing the request. Except when responding to a HEAD request, the server <em class="bcp14">SHOULD</em> include a representation containing an explanation of the error situation, and whether it is a temporary or permanent condition.
    1916          User agents <em class="bcp14">SHOULD</em> display any included representation to the user. These response codes are applicable to any request method.
    1917       </p>
    1918       <div id="rfc.iref.58"></div>
    1919       <div id="rfc.iref.s.38"></div>
    1920       <h3 id="rfc.section.8.5.1"><a href="#rfc.section.8.5.1">8.5.1</a>&nbsp;<a id="status.500" href="#status.500">500 Internal Server Error</a></h3>
    1921       <p id="rfc.section.8.5.1.p.1">The server encountered an unexpected condition which prevented it from fulfilling the request.</p>
    1922       <div id="rfc.iref.59"></div>
    1923       <div id="rfc.iref.s.39"></div>
    1924       <h3 id="rfc.section.8.5.2"><a href="#rfc.section.8.5.2">8.5.2</a>&nbsp;<a id="status.501" href="#status.501">501 Not Implemented</a></h3>
    1925       <p id="rfc.section.8.5.2.p.1">The server does not support the functionality required to fulfill the request. This is the appropriate response when the server
    1926          does not recognize the request method and is not capable of supporting it for any resource.
    1927       </p>
    1928       <div id="rfc.iref.60"></div>
    1929       <div id="rfc.iref.s.40"></div>
    1930       <h3 id="rfc.section.8.5.3"><a href="#rfc.section.8.5.3">8.5.3</a>&nbsp;<a id="status.502" href="#status.502">502 Bad Gateway</a></h3>
    1931       <p id="rfc.section.8.5.3.p.1">The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting
    1932          to fulfill the request.
    1933       </p>
    1934       <div id="rfc.iref.61"></div>
    1935       <div id="rfc.iref.s.41"></div>
    1936       <h3 id="rfc.section.8.5.4"><a href="#rfc.section.8.5.4">8.5.4</a>&nbsp;<a id="status.503" href="#status.503">503 Service Unavailable</a></h3>
    1937       <p id="rfc.section.8.5.4.p.1">The server is currently unable or unwilling to handle the request due to reasons such as temporary overloading, maintenance
    1938          of the server, or rate limiting of the client.
    1939       </p>
    1940       <p id="rfc.section.8.5.4.p.2">The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the
    1941          delay <em class="bcp14">MAY</em> be indicated in a Retry-After header field (<a href="#header.retry-after" id="rfc.xref.header.retry-after.2" title="Retry-After">Section&nbsp;9.7</a>). If no Retry-After is given, the client <em class="bcp14">SHOULD</em> handle the response as it would for a 500 response.
    1942       </p>
    1943       <div class="note" id="rfc.section.8.5.4.p.3">
    1944          <p> <b>Note:</b> The existence of the 503 status code does not imply that a server must use it when becoming overloaded. Some servers might
    1945             wish to simply refuse the connection.
    1946          </p>
     2057                  alternative courses which may be available to the user.
     2058               </p>
     2059            </div>
     2060         </div>
     2061         <div id="status.5xx">
     2062            <h2 id="rfc.section.8.5"><a href="#rfc.section.8.5">8.5</a>&nbsp;<a href="#status.5xx">Server Error 5xx</a></h2>
     2063            <p id="rfc.section.8.5.p.1">Response status codes beginning with the digit "5" indicate cases in which the server is aware that it has erred or is incapable
     2064               of performing the request. Except when responding to a HEAD request, the server <em class="bcp14">SHOULD</em> include a representation containing an explanation of the error situation, and whether it is a temporary or permanent condition.
     2065               User agents <em class="bcp14">SHOULD</em> display any included representation to the user. These response codes are applicable to any request method.
     2066            </p>
     2067            <div id="status.500">
     2068               <div id="rfc.iref.5.1"></div>
     2069               <div id="rfc.iref.s.38"></div>
     2070               <h3 id="rfc.section.8.5.1"><a href="#rfc.section.8.5.1">8.5.1</a>&nbsp;<a href="#status.500">500 Internal Server Error</a></h3>
     2071               <p id="rfc.section.8.5.1.p.1">The server encountered an unexpected condition which prevented it from fulfilling the request.</p>
     2072            </div>
     2073            <div id="status.501">
     2074               <div id="rfc.iref.5.2"></div>
     2075               <div id="rfc.iref.s.39"></div>
     2076               <h3 id="rfc.section.8.5.2"><a href="#rfc.section.8.5.2">8.5.2</a>&nbsp;<a href="#status.501">501 Not Implemented</a></h3>
     2077               <p id="rfc.section.8.5.2.p.1">The server does not support the functionality required to fulfill the request. This is the appropriate response when the server
     2078                  does not recognize the request method and is not capable of supporting it for any resource.
     2079               </p>
     2080            </div>
     2081            <div id="status.502">
     2082               <div id="rfc.iref.5.3"></div>
     2083               <div id="rfc.iref.s.40"></div>
     2084               <h3 id="rfc.section.8.5.3"><a href="#rfc.section.8.5.3">8.5.3</a>&nbsp;<a href="#status.502">502 Bad Gateway</a></h3>
     2085               <p id="rfc.section.8.5.3.p.1">The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting
     2086                  to fulfill the request.
     2087               </p>
     2088            </div>
     2089            <div id="status.503">
     2090               <div id="rfc.iref.5.4"></div>
     2091               <div id="rfc.iref.s.41"></div>
     2092               <h3 id="rfc.section.8.5.4"><a href="#rfc.section.8.5.4">8.5.4</a>&nbsp;<a href="#status.503">503 Service Unavailable</a></h3>
     2093               <p id="rfc.section.8.5.4.p.1">The server is currently unable or unwilling to handle the request due to reasons such as temporary overloading, maintenance
     2094                  of the server, or rate limiting of the client.
     2095               </p>
     2096               <p id="rfc.section.8.5.4.p.2">The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the
     2097                  delay <em class="bcp14">MAY</em> be indicated in a Retry-After header field (<a href="#header.retry-after" id="rfc.xref.header.retry-after.2" title="Retry-After">Section&nbsp;9.7</a>). If no Retry-After is given, the client <em class="bcp14">SHOULD</em> handle the response as it would for a 500 response.
     2098               </p>
     2099               <div class="note" id="rfc.section.8.5.4.p.3">
     2100                  <p><b>Note:</b> The existence of the 503 status code does not imply that a server must use it when becoming overloaded. Some servers might
     2101                     wish to simply refuse the connection.
     2102                  </p>
     2103               </div>
     2104            </div>
     2105            <div id="status.504">
     2106               <div id="rfc.iref.5.5"></div>
     2107               <div id="rfc.iref.s.42"></div>
     2108               <h3 id="rfc.section.8.5.5"><a href="#rfc.section.8.5.5">8.5.5</a>&nbsp;<a href="#status.504">504 Gateway Timeout</a></h3>
     2109               <p id="rfc.section.8.5.5.p.1">The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the
     2110                  URI (e.g., HTTP, FTP, LDAP) or some other auxiliary server (e.g., DNS) it needed to access in attempting to complete the request.
     2111               </p>
     2112               <div class="note" id="rfc.section.8.5.5.p.2">
     2113                  <p><b>Note</b> to implementors: some deployed proxies are known to return 400 or 500 when DNS lookups time out.
     2114                  </p>
     2115               </div>
     2116            </div>
     2117            <div id="status.505">
     2118               <div id="rfc.iref.5.6"></div>
     2119               <div id="rfc.iref.s.43"></div>
     2120               <h3 id="rfc.section.8.5.6"><a href="#rfc.section.8.5.6">8.5.6</a>&nbsp;<a href="#status.505">505 HTTP Version Not Supported</a></h3>
     2121               <p id="rfc.section.8.5.6.p.1">The server does not support, or refuses to support, the protocol version that was used in the request message. The server
     2122                  is indicating that it is unable or unwilling to complete the request using the same major version as the client, as described
     2123                  in <a href="p1-messaging.html#http.version" title="Protocol Versioning">Section 2.6</a> of <a href="#Part1" id="rfc.xref.Part1.30"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, other than with this error message. The response <em class="bcp14">SHOULD</em> contain a representation describing why that version is not supported and what other protocols are supported by that server.
     2124               </p>
     2125            </div>
     2126         </div>
    19472127      </div>
    1948       <div id="rfc.iref.62"></div>
    1949       <div id="rfc.iref.s.42"></div>
    1950       <h3 id="rfc.section.8.5.5"><a href="#rfc.section.8.5.5">8.5.5</a>&nbsp;<a id="status.504" href="#status.504">504 Gateway Timeout</a></h3>
    1951       <p id="rfc.section.8.5.5.p.1">The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server specified by the
    1952          URI (e.g., HTTP, FTP, LDAP) or some other auxiliary server (e.g., DNS) it needed to access in attempting to complete the request.
    1953       </p>
    1954       <div class="note" id="rfc.section.8.5.5.p.2">
    1955          <p> <b>Note</b> to implementors: some deployed proxies are known to return 400 or 500 when DNS lookups time out.
    1956          </p>
    1957       </div>
    1958       <div id="rfc.iref.63"></div>
    1959       <div id="rfc.iref.s.43"></div>
    1960       <h3 id="rfc.section.8.5.6"><a href="#rfc.section.8.5.6">8.5.6</a>&nbsp;<a id="status.505" href="#status.505">505 HTTP Version Not Supported</a></h3>
    1961       <p id="rfc.section.8.5.6.p.1">The server does not support, or refuses to support, the protocol version that was used in the request message. The server
    1962          is indicating that it is unable or unwilling to complete the request using the same major version as the client, as described
    1963          in <a href="p1-messaging.html#http.version" title="Protocol Versioning">Section 2.6</a> of <a href="#Part1" id="rfc.xref.Part1.30"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, other than with this error message. The response <em class="bcp14">SHOULD</em> contain a representation describing why that version is not supported and what other protocols are supported by that server.
    1964       </p>
    1965       <h1 id="rfc.section.9"><a href="#rfc.section.9">9.</a>&nbsp;<a id="header.fields" href="#header.fields">Header Field Definitions</a></h1>
    1966       <p id="rfc.section.9.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to request and response semantics.</p>
    1967       <div id="rfc.iref.a.1"></div>
    1968       <div id="rfc.iref.h.2"></div>
    1969       <h2 id="rfc.section.9.1"><a href="#rfc.section.9.1">9.1</a>&nbsp;<a id="header.allow" href="#header.allow">Allow</a></h2>
    1970       <p id="rfc.section.9.1.p.1">The "Allow" header field lists the set of methods advertised as supported by the target resource. The purpose of this field
    1971          is strictly to inform the recipient of valid request methods associated with the resource.
    1972       </p>
    1973       <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.6"></span>  <a href="#header.allow" class="smpl">Allow</a> = #<a href="#method" class="smpl">Method</a>
     2128      <div id="header.fields">
     2129         <h1 id="rfc.section.9"><a href="#rfc.section.9">9.</a>&nbsp;<a href="#header.fields">Header Field Definitions</a></h1>
     2130         <p id="rfc.section.9.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to request and response semantics.</p>
     2131         <div id="header.allow">
     2132            <div id="rfc.iref.a.1"></div>
     2133            <div id="rfc.iref.h.2"></div>
     2134            <h2 id="rfc.section.9.1"><a href="#rfc.section.9.1">9.1</a>&nbsp;<a href="#header.allow">Allow</a></h2>
     2135            <p id="rfc.section.9.1.p.1">The "Allow" header field lists the set of methods advertised as supported by the target resource. The purpose of this field
     2136               is strictly to inform the recipient of valid request methods associated with the resource.
     2137            </p>
     2138            <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.6"></span>  <a href="#header.allow" class="smpl">Allow</a> = #<a href="#method" class="smpl">Method</a>
    19742139</pre><p id="rfc.section.9.1.p.3">Example of use:</p>
    1975       <div id="rfc.figure.u.9"></div><pre class="text">  Allow: GET, HEAD, PUT
     2140            <div id="rfc.figure.u.9"></div><pre class="text">  Allow: GET, HEAD, PUT
    19762141</pre><p id="rfc.section.9.1.p.5">The actual set of allowed methods is defined by the origin server at the time of each request.</p>
    1977       <p id="rfc.section.9.1.p.6">A proxy <em class="bcp14">MUST NOT</em> modify the Allow header field — it does not need to understand all the methods specified in order to handle them according
    1978          to the generic message handling rules.
    1979       </p>
    1980       <div id="rfc.iref.e.1"></div>
    1981       <div id="rfc.iref.h.3"></div>
    1982       <h2 id="rfc.section.9.2"><a href="#rfc.section.9.2">9.2</a>&nbsp;<a id="header.expect" href="#header.expect">Expect</a></h2>
    1983       <p id="rfc.section.9.2.p.1">The "Expect" header field is used to indicate that particular server behaviors are required by the client.</p>
    1984       <div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span>  <a href="#header.expect" class="smpl">Expect</a>       = 1#<a href="#header.expect" class="smpl">expectation</a>
     2142            <p id="rfc.section.9.1.p.6">A proxy <em class="bcp14">MUST NOT</em> modify the Allow header field — it does not need to understand all the methods specified in order to handle them according
     2143               to the generic message handling rules.
     2144            </p>
     2145         </div>
     2146         <div id="header.expect">
     2147            <div id="rfc.iref.e.1"></div>
     2148            <div id="rfc.iref.h.3"></div>
     2149            <h2 id="rfc.section.9.2"><a href="#rfc.section.9.2">9.2</a>&nbsp;<a href="#header.expect">Expect</a></h2>
     2150            <p id="rfc.section.9.2.p.1">The "Expect" header field is used to indicate that particular server behaviors are required by the client.</p>
     2151            <div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span><span id="rfc.iref.g.10"></span>  <a href="#header.expect" class="smpl">Expect</a>       = 1#<a href="#header.expect" class="smpl">expectation</a>
    19852152 
    19862153  <a href="#header.expect" class="smpl">expectation</a>  = "100-continue" / <a href="#header.expect" class="smpl">expectation-extension</a>
     
    19892156  <a href="#header.expect" class="smpl">expect-params</a> = ";" <a href="#core.rules" class="smpl">token</a> [ "=" ( <a href="#core.rules" class="smpl">token</a> / <a href="#core.rules" class="smpl">quoted-string</a> ) ]
    19902157</pre><p id="rfc.section.9.2.p.3">A server that does not understand or is unable to comply with any of the expectation values in the Expect field of a request <em class="bcp14">MUST</em> respond with appropriate error status code. The server <em class="bcp14">MUST</em> respond with a 417 (Expectation Failed) status code if any of the expectations cannot be met or, if there are other problems
    1991          with the request, some other 4xx status code.
    1992       </p>
    1993       <p id="rfc.section.9.2.p.4">This header field is defined with extensible syntax to allow for future extensions. If a server receives a request containing
    1994          an Expect field that includes an expectation-extension that it does not support, it <em class="bcp14">MUST</em> respond with a 417 (Expectation Failed) status code.
    1995       </p>
    1996       <p id="rfc.section.9.2.p.5">Comparison of expectation values is case-insensitive for unquoted tokens (including the 100-continue token), and is case-sensitive
    1997          for quoted-string expectation-extensions.
    1998       </p>
    1999       <p id="rfc.section.9.2.p.6">The Expect mechanism is hop-by-hop: that is, an HTTP/1.1 proxy <em class="bcp14">MUST</em> return a 417 (Expectation Failed) status code if it receives a request with an expectation that it cannot meet. However, the
    2000          Expect header field itself is end-to-end; it <em class="bcp14">MUST</em> be forwarded if the request is forwarded.
    2001       </p>
    2002       <p id="rfc.section.9.2.p.7">Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header field.</p>
    2003       <p id="rfc.section.9.2.p.8">See <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 7.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.31"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> for the use of the 100 (Continue) status code.
    2004       </p>
    2005       <div id="rfc.iref.f.1"></div>
    2006       <div id="rfc.iref.h.4"></div>
    2007       <h2 id="rfc.section.9.3"><a href="#rfc.section.9.3">9.3</a>&nbsp;<a id="header.from" href="#header.from">From</a></h2>
    2008       <p id="rfc.section.9.3.p.1">The "From" header field, if given, <em class="bcp14">SHOULD</em> contain an Internet e-mail address for the human user who controls the requesting user agent. The address <em class="bcp14">SHOULD</em> be machine-usable, as defined by "mailbox" in <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.1"><cite title="Internet Message Format">[RFC5322]</cite></a>:
    2009       </p>
    2010       <div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.11"></span>  <a href="#header.from" class="smpl">From</a>    = <a href="#header.from" class="smpl">mailbox</a>
     2158               with the request, some other 4xx status code.
     2159            </p>
     2160            <p id="rfc.section.9.2.p.4">This header field is defined with extensible syntax to allow for future extensions. If a server receives a request containing
     2161               an Expect field that includes an expectation-extension that it does not support, it <em class="bcp14">MUST</em> respond with a 417 (Expectation Failed) status code.
     2162            </p>
     2163            <p id="rfc.section.9.2.p.5">Comparison of expectation values is case-insensitive for unquoted tokens (including the 100-continue token), and is case-sensitive
     2164               for quoted-string expectation-extensions.
     2165            </p>
     2166            <p id="rfc.section.9.2.p.6">The Expect mechanism is hop-by-hop: that is, an HTTP/1.1 proxy <em class="bcp14">MUST</em> return a 417 (Expectation Failed) status code if it receives a request with an expectation that it cannot meet. However, the
     2167               Expect header field itself is end-to-end; it <em class="bcp14">MUST</em> be forwarded if the request is forwarded.
     2168            </p>
     2169            <p id="rfc.section.9.2.p.7">Many older HTTP/1.0 and HTTP/1.1 applications do not understand the Expect header field.</p>
     2170            <p id="rfc.section.9.2.p.8">See <a href="p1-messaging.html#use.of.the.100.status" title="Use of the 100 (Continue) Status">Section 7.2.3</a> of <a href="#Part1" id="rfc.xref.Part1.31"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> for the use of the 100 (Continue) status code.
     2171            </p>
     2172         </div>
     2173         <div id="header.from">
     2174            <div id="rfc.iref.f.1"></div>
     2175            <div id="rfc.iref.h.4"></div>
     2176            <h2 id="rfc.section.9.3"><a href="#rfc.section.9.3">9.3</a>&nbsp;<a href="#header.from">From</a></h2>
     2177            <p id="rfc.section.9.3.p.1">The "From" header field, if given, <em class="bcp14">SHOULD</em> contain an Internet e-mail address for the human user who controls the requesting user agent. The address <em class="bcp14">SHOULD</em> be machine-usable, as defined by "mailbox" in <a href="https://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.1"><cite title="Internet Message Format">[RFC5322]</cite></a>:
     2178            </p>
     2179            <div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.11"></span>  <a href="#header.from" class="smpl">From</a>    = <a href="#header.from" class="smpl">mailbox</a>
    20112180 
    2012   <a href="#header.from" class="smpl">mailbox</a> = &lt;mailbox, defined in <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a>&gt;
     2181  <a href="#header.from" class="smpl">mailbox</a> = &lt;mailbox, defined in <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="https://tools.ietf.org/html/rfc5322#section-3.4">Section 3.4</a>&gt;
    20132182</pre><p id="rfc.section.9.3.p.3">An example is:</p>
    2014       <div id="rfc.figure.u.12"></div><pre class="text">  From: webmaster@example.org
     2183            <div id="rfc.figure.u.12"></div><pre class="text">  From: webmaster@example.org
    20152184</pre><p id="rfc.section.9.3.p.5">This header field <em class="bcp14">MAY</em> be used for logging purposes and as a means for identifying the source of invalid or unwanted requests. It <em class="bcp14">SHOULD NOT</em> be used as an insecure form of access protection. The interpretation of this field is that the request is being performed
    2016          on behalf of the person given, who accepts responsibility for the method performed. In particular, robot agents <em class="bcp14">SHOULD</em> include this header field so that the person responsible for running the robot can be contacted if problems occur on the receiving
    2017          end.
    2018       </p>
    2019       <p id="rfc.section.9.3.p.6">The Internet e-mail address in this field <em class="bcp14">MAY</em> be separate from the Internet host which issued the request. For example, when a request is passed through a proxy the original
    2020          issuer's address <em class="bcp14">SHOULD</em> be used.
    2021       </p>
    2022       <p id="rfc.section.9.3.p.7">The client <em class="bcp14">SHOULD NOT</em> send the From header field without the user's approval, as it might conflict with the user's privacy interests or their site's
    2023          security policy. It is strongly recommended that the user be able to disable, enable, and modify the value of this field at
    2024          any time prior to a request.
    2025       </p>
    2026       <div id="rfc.iref.l.1"></div>
    2027       <div id="rfc.iref.h.5"></div>
    2028       <h2 id="rfc.section.9.4"><a href="#rfc.section.9.4">9.4</a>&nbsp;<a id="header.location" href="#header.location">Location</a></h2>
    2029       <p id="rfc.section.9.4.p.1">The "Location" header field is used to identify a newly created resource, or to redirect the recipient to a different location
    2030          for completion of the request.
    2031       </p>
    2032       <p id="rfc.section.9.4.p.2">For 201 (Created) responses, the Location is the URI of the new resource which was created by the request. For 3xx responses,
    2033          the location <em class="bcp14">SHOULD</em> indicate the server's preferred URI for automatic redirection to the resource.
    2034       </p>
    2035       <p id="rfc.section.9.4.p.3">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-5">Section 5</a>).
    2036       </p>
    2037       <div id="rfc.figure.u.13"></div><pre class="inline"><span id="rfc.iref.g.12"></span>  <a href="#header.location" class="smpl">Location</a> = <a href="#abnf.dependencies" class="smpl">URI-reference</a>
    2038 </pre><div id="rfc.figure.u.14"></div>
    2039       <p>Examples are:</p>  <pre class="text">  Location: http://www.example.org/pub/WWW/People.html#tim
     2185               on behalf of the person given, who accepts responsibility for the method performed. In particular, robot agents <em class="bcp14">SHOULD</em> include this header field so that the person responsible for running the robot can be contacted if problems occur on the receiving
     2186               end.
     2187            </p>
     2188            <p id="rfc.section.9.3.p.6">The Internet e-mail address in this field <em class="bcp14">MAY</em> be separate from the Internet host which issued the request. For example, when a request is passed through a proxy the original
     2189               issuer's address <em class="bcp14">SHOULD</em> be used.
     2190            </p>
     2191            <p id="rfc.section.9.3.p.7">The client <em class="bcp14">SHOULD NOT</em> send the From header field without the user's approval, as it might conflict with the user's privacy interests or their site's
     2192               security policy. It is strongly recommended that the user be able to disable, enable, and modify the value of this field at
     2193               any time prior to a request.
     2194            </p>
     2195         </div>
     2196         <div id="header.location">
     2197            <div id="rfc.iref.l.1"></div>
     2198            <div id="rfc.iref.h.5"></div>
     2199            <h2 id="rfc.section.9.4"><a href="#rfc.section.9.4">9.4</a>&nbsp;<a href="#header.location">Location</a></h2>
     2200            <p id="rfc.section.9.4.p.1">The "Location" header field is used to identify a newly created resource, or to redirect the recipient to a different location
     2201               for completion of the request.
     2202            </p>
     2203            <p id="rfc.section.9.4.p.2">For 201 (Created) responses, the Location is the URI of the new resource which was created by the request. For 3xx responses,
     2204               the location <em class="bcp14">SHOULD</em> indicate the server's preferred URI for automatic redirection to the resource.
     2205            </p>
     2206            <p id="rfc.section.9.4.p.3">The field value consists of a single URI-reference. When it has the form of a relative reference (<a href="#RFC3986" id="rfc.xref.RFC3986.1"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="https://tools.ietf.org/html/rfc3986#section-4.2">Section 4.2</a>), the final value is computed by resolving it against the effective request URI (<a href="#RFC3986" id="rfc.xref.RFC3986.2"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="https://tools.ietf.org/html/rfc3986#section-5">Section 5</a>).
     2207            </p>
     2208            <div id="rfc.figure.u.13"></div><pre class="inline"><span id="rfc.iref.g.12"></span>  <a href="#header.location" class="smpl">Location</a> = <a href="#abnf.dependencies" class="smpl">URI-reference</a>
     2209</pre><div id="rfc.figure.u.14"></div>
     2210            <p>Examples are:</p><pre class="text">  Location: http://www.example.org/pub/WWW/People.html#tim
    20402211</pre><div id="rfc.figure.u.15"></div><pre class="text">  Location: /index.html
    20412212</pre><p id="rfc.section.9.4.p.7">There are circumstances in which a fragment identifier in a Location URI would not be appropriate. For instance, when it appears
    2042          in a 201 Created response, where the Location header field specifies the URI for the entire created resource.
    2043       </p>
    2044       <div class="note" id="rfc.section.9.4.p.8">
    2045          <p> <b>Note:</b> This specification does not define precedence rules for the case where the original URI, as navigated to by the user agent,
    2046             and the Location header field value both contain fragment identifiers. Thus be aware that including fragment identifiers might
    2047             inconvenience anyone relying on the semantics of the original URI's fragment identifier.
    2048          </p>
    2049       </div>
    2050       <div class="note" id="rfc.section.9.4.p.9">
    2051          <p> <b>Note:</b> The Content-Location header field (<a href="p3-payload.html#header.content-location" title="Content-Location">Section 6.7</a> of <a href="#Part3" id="rfc.xref.Part3.8"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation.
    2052             It is therefore possible for a response to contain header fields for both Location and Content-Location.
    2053          </p>
    2054       </div>
    2055       <div id="rfc.iref.m.9"></div>
    2056       <div id="rfc.iref.h.6"></div>
    2057       <h2 id="rfc.section.9.5"><a href="#rfc.section.9.5">9.5</a>&nbsp;<a id="header.max-forwards" href="#header.max-forwards">Max-Forwards</a></h2>
    2058       <p id="rfc.section.9.5.p.1">The "Max-Forwards" header field provides a mechanism with the TRACE (<a href="#TRACE" id="rfc.xref.TRACE.2" title="TRACE">Section&nbsp;7.8</a>) and OPTIONS (<a href="#OPTIONS" id="rfc.xref.OPTIONS.2" title="OPTIONS">Section&nbsp;7.2</a>) methods to limit the number of times that the request is forwarded by proxies. This can be useful when the client is attempting
    2059          to trace a request which appears to be failing or looping in mid-chain.
    2060       </p>
    2061       <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.13"></span>  <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*<a href="#notation" class="smpl">DIGIT</a>
     2213               in a 201 Created response, where the Location header field specifies the URI for the entire created resource.
     2214            </p>
     2215            <div class="note" id="rfc.section.9.4.p.8">
     2216               <p><b>Note:</b> This specification does not define precedence rules for the case where the original URI, as navigated to by the user agent,
     2217                  and the Location header field value both contain fragment identifiers. Thus be aware that including fragment identifiers might
     2218                  inconvenience anyone relying on the semantics of the original URI's fragment identifier.
     2219               </p>
     2220            </div>
     2221            <div class="note" id="rfc.section.9.4.p.9">
     2222               <p><b>Note:</b> The Content-Location header field (<a href="p3-payload.html#header.content-location" title="Content-Location">Section 6.7</a> of <a href="#Part3" id="rfc.xref.Part3.8"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) differs from Location in that the Content-Location identifies the most specific resource corresponding to the enclosed representation.
     2223                  It is therefore possible for a response to contain header fields for both Location and Content-Location.
     2224               </p>
     2225            </div>
     2226         </div>
     2227         <div id="header.max-forwards">
     2228            <div id="rfc.iref.m.9"></div>
     2229            <div id="rfc.iref.h.6"></div>
     2230            <h2 id="rfc.section.9.5"><a href="#rfc.section.9.5">9.5</a>&nbsp;<a href="#header.max-forwards">Max-Forwards</a></h2>
     2231            <p id="rfc.section.9.5.p.1">The "Max-Forwards" header field provides a mechanism with the TRACE (<a href="#TRACE" id="rfc.xref.TRACE.2" title="TRACE">Section&nbsp;7.8</a>) and OPTIONS (<a href="#OPTIONS" id="rfc.xref.OPTIONS.2" title="OPTIONS">Section&nbsp;7.2</a>) methods to limit the number of times that the request is forwarded by proxies. This can be useful when the client is attempting
     2232               to trace a request which appears to be failing or looping in mid-chain.
     2233            </p>
     2234            <div id="rfc.figure.u.16"></div><pre class="inline"><span id="rfc.iref.g.13"></span>  <a href="#header.max-forwards" class="smpl">Max-Forwards</a> = 1*<a href="#notation" class="smpl">DIGIT</a>
    20622235</pre><p id="rfc.section.9.5.p.3">The Max-Forwards value is a decimal integer indicating the remaining number of times this request message can be forwarded.</p>
    2063       <p id="rfc.section.9.5.p.4">Each recipient of a TRACE or OPTIONS request containing a Max-Forwards header field <em class="bcp14">MUST</em> check and update its value prior to forwarding the request. If the received value is zero (0), the recipient <em class="bcp14">MUST NOT</em> forward the request; instead, it <em class="bcp14">MUST</em> respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message <em class="bcp14">MUST</em> contain an updated Max-Forwards field with a value decremented by one (1).
    2064       </p>
    2065       <p id="rfc.section.9.5.p.5">The Max-Forwards header field <em class="bcp14">MAY</em> be ignored for all other request methods.
    2066       </p>
    2067       <div id="rfc.iref.r.1"></div>
    2068       <div id="rfc.iref.h.7"></div>
    2069       <h2 id="rfc.section.9.6"><a href="#rfc.section.9.6">9.6</a>&nbsp;<a id="header.referer" href="#header.referer">Referer</a></h2>
    2070       <p id="rfc.section.9.6.p.1">The "Referer" [sic] header field allows the client to specify the URI of the resource from which the effective request URI
    2071          was obtained (the "referrer", although the header field is misspelled.).
    2072       </p>
    2073       <p id="rfc.section.9.6.p.2">The Referer header field allows servers to generate lists of back-links to resources for interest, logging, optimized caching,
    2074          etc. It also allows obsolete or mistyped links to be traced for maintenance. Some servers use Referer as a means of controlling
    2075          where they allow links from (so-called "deep linking"), but legitimate requests do not always contain a Referer header field.
    2076       </p>
    2077       <p id="rfc.section.9.6.p.3">If the effective request URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard),
    2078          the Referer field <em class="bcp14">MUST</em> either be sent with the value "about:blank", or not be sent at all. Note that this requirement does not apply to sources with
    2079          non-HTTP URIs (e.g., FTP).
    2080       </p>
    2081       <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.14"></span>  <a href="#header.referer" class="smpl">Referer</a> = <a href="#abnf.dependencies" class="smpl">absolute-URI</a> / <a href="#abnf.dependencies" class="smpl">partial-URI</a>
     2236            <p id="rfc.section.9.5.p.4">Each recipient of a TRACE or OPTIONS request containing a Max-Forwards header field <em class="bcp14">MUST</em> check and update its value prior to forwarding the request. If the received value is zero (0), the recipient <em class="bcp14">MUST NOT</em> forward the request; instead, it <em class="bcp14">MUST</em> respond as the final recipient. If the received Max-Forwards value is greater than zero, then the forwarded message <em class="bcp14">MUST</em> contain an updated Max-Forwards field with a value decremented by one (1).
     2237            </p>
     2238            <p id="rfc.section.9.5.p.5">The Max-Forwards header field <em class="bcp14">MAY</em> be ignored for all other request methods.
     2239            </p>
     2240         </div>
     2241         <div id="header.referer">
     2242            <div id="rfc.iref.r.1"></div>
     2243            <div id="rfc.iref.h.7"></div>
     2244            <h2 id="rfc.section.9.6"><a href="#rfc.section.9.6">9.6</a>&nbsp;<a href="#header.referer">Referer</a></h2>
     2245            <p id="rfc.section.9.6.p.1">The "Referer" [sic] header field allows the client to specify the URI of the resource from which the effective request URI
     2246               was obtained (the "referrer", although the header field is misspelled.).
     2247            </p>
     2248            <p id="rfc.section.9.6.p.2">The Referer header field allows servers to generate lists of back-links to resources for interest, logging, optimized caching,
     2249               etc. It also allows obsolete or mistyped links to be traced for maintenance. Some servers use Referer as a means of controlling
     2250               where they allow links from (so-called "deep linking"), but legitimate requests do not always contain a Referer header field.
     2251            </p>
     2252            <p id="rfc.section.9.6.p.3">If the effective request URI was obtained from a source that does not have its own URI (e.g., input from the user keyboard),
     2253               the Referer field <em class="bcp14">MUST</em> either be sent with the value "about:blank", or not be sent at all. Note that this requirement does not apply to sources with
     2254               non-HTTP URIs (e.g., FTP).
     2255            </p>
     2256            <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.14"></span>  <a href="#header.referer" class="smpl">Referer</a> = <a href="#abnf.dependencies" class="smpl">absolute-URI</a> / <a href="#abnf.dependencies" class="smpl">partial-URI</a>
    20822257</pre><p id="rfc.section.9.6.p.5">Example:</p>
    2083       <div id="rfc.figure.u.18"></div><pre class="text">  Referer: http://www.example.org/hypertext/Overview.html
     2258            <div id="rfc.figure.u.18"></div><pre class="text">  Referer: http://www.example.org/hypertext/Overview.html
    20842259</pre><p id="rfc.section.9.6.p.7">If the field value is a relative URI, it <em class="bcp14">SHOULD</em> be interpreted relative to the effective request URI. The URI <em class="bcp14">MUST NOT</em> include a fragment. See <a href="#encoding.sensitive.information.in.uris" title="Encoding Sensitive Information in URIs">Section&nbsp;11.2</a> for security considerations.
    2085       </p>
    2086       <div id="rfc.iref.r.2"></div>
    2087       <div id="rfc.iref.h.8"></div>
    2088       <h2 id="rfc.section.9.7"><a href="#rfc.section.9.7">9.7</a>&nbsp;<a id="header.retry-after" href="#header.retry-after">Retry-After</a></h2>
    2089       <p id="rfc.section.9.7.p.1">The header "Retry-After" field can be used with a 503 (Service Unavailable) response to indicate how long the service is expected
    2090          to be unavailable to the requesting client. This field <em class="bcp14">MAY</em> also be used with any 3xx (Redirection) response to indicate the minimum time the user-agent is asked wait before issuing
    2091          the redirected request.
    2092       </p>
    2093       <p id="rfc.section.9.7.p.2">The value of this field can be either an HTTP-date or an integer number of seconds (in decimal) after the time of the response.</p>
    2094       <div id="rfc.figure.u.19"></div><pre class="inline"><span id="rfc.iref.g.15"></span>  <a href="#header.retry-after" class="smpl">Retry-After</a> = <a href="#abnf.dependencies" class="smpl">HTTP-date</a> / <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>
     2260            </p>
     2261         </div>
     2262         <div id="header.retry-after">
     2263            <div id="rfc.iref.r.2"></div>
     2264            <div id="rfc.iref.h.8"></div>
     2265            <h2 id="rfc.section.9.7"><a href="#rfc.section.9.7">9.7</a>&nbsp;<a href="#header.retry-after">Retry-After</a></h2>
     2266            <p id="rfc.section.9.7.p.1">The header "Retry-After" field can be used with a 503 (Service Unavailable) response to indicate how long the service is expected
     2267               to be unavailable to the requesting client. This field <em class="bcp14">MAY</em> also be used with any 3xx (Redirection) response to indicate the minimum time the user-agent is asked wait before issuing
     2268               the redirected request.
     2269            </p>
     2270            <p id="rfc.section.9.7.p.2">The value of this field can be either an HTTP-date or an integer number of seconds (in decimal) after the time of the response.</p>
     2271            <div id="rfc.figure.u.19"></div><pre class="inline"><span id="rfc.iref.g.15"></span>  <a href="#header.retry-after" class="smpl">Retry-After</a> = <a href="#abnf.dependencies" class="smpl">HTTP-date</a> / <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>
    20952272</pre><div id="rule.delta-seconds">
    2096          <p id="rfc.section.9.7.p.4"> Time spans are non-negative decimal integers, representing time in seconds.</p>
    2097       </div>
    2098       <div id="rfc.figure.u.20"></div><pre class="inline"><span id="rfc.iref.g.16"></span>  <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>  = 1*<a href="#notation" class="smpl">DIGIT</a>
     2273               <p id="rfc.section.9.7.p.4"> Time spans are non-negative decimal integers, representing time in seconds.</p>
     2274            </div>
     2275            <div id="rfc.figure.u.20"></div><pre class="inline"><span id="rfc.iref.g.16"></span>  <a href="#rule.delta-seconds" class="smpl">delta-seconds</a>  = 1*<a href="#notation" class="smpl">DIGIT</a>
    20992276</pre><p id="rfc.section.9.7.p.6">Two examples of its use are</p>
    2100       <div id="rfc.figure.u.21"></div><pre class="text">  Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
     2277            <div id="rfc.figure.u.21"></div><pre class="text">  Retry-After: Fri, 31 Dec 1999 23:59:59 GMT
    21012278  Retry-After: 120
    21022279</pre><p id="rfc.section.9.7.p.8">In the latter example, the delay is 2 minutes.</p>
    2103       <div id="rfc.iref.s.44"></div>
    2104       <div id="rfc.iref.h.9"></div>
    2105       <h2 id="rfc.section.9.8"><a href="#rfc.section.9.8">9.8</a>&nbsp;<a id="header.server" href="#header.server">Server</a></h2>
    2106       <p id="rfc.section.9.8.p.1">The "Server" header field contains information about the software used by the origin server to handle the request.</p>
    2107       <p id="rfc.section.9.8.p.2">The field can contain multiple product tokens (<a href="p1-messaging.html#product.tokens" title="Product Tokens">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1.32"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.33"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for
    2108          identifying the application.
    2109       </p>
    2110       <div id="rfc.figure.u.22"></div><pre class="inline"><span id="rfc.iref.g.17"></span>  <a href="#header.server" class="smpl">Server</a> = <a href="#abnf.dependencies" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#abnf.dependencies" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
     2280         </div>
     2281         <div id="header.server">
     2282            <div id="rfc.iref.s.44"></div>
     2283            <div id="rfc.iref.h.9"></div>
     2284            <h2 id="rfc.section.9.8"><a href="#rfc.section.9.8">9.8</a>&nbsp;<a href="#header.server">Server</a></h2>
     2285            <p id="rfc.section.9.8.p.1">The "Server" header field contains information about the software used by the origin server to handle the request.</p>
     2286            <p id="rfc.section.9.8.p.2">The field can contain multiple product tokens (<a href="p1-messaging.html#product.tokens" title="Product Tokens">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1.32"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.33"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) identifying the server and any significant subproducts. The product tokens are listed in order of their significance for
     2287               identifying the application.
     2288            </p>
     2289            <div id="rfc.figure.u.22"></div><pre class="inline"><span id="rfc.iref.g.17"></span>  <a href="#header.server" class="smpl">Server</a> = <a href="#abnf.dependencies" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#abnf.dependencies" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
    21112290</pre><p id="rfc.section.9.8.p.4">Example:</p>
    2112       <div id="rfc.figure.u.23"></div><pre class="text">  Server: CERN/3.0 libwww/2.17
     2291            <div id="rfc.figure.u.23"></div><pre class="text">  Server: CERN/3.0 libwww/2.17
    21132292</pre><p id="rfc.section.9.8.p.6">If the response is being forwarded through a proxy, the proxy application <em class="bcp14">MUST NOT</em> modify the Server header field. Instead, it <em class="bcp14">MUST</em> include a Via field (as described in <a href="p1-messaging.html#header.via" title="Via">Section 9.9</a> of <a href="#Part1" id="rfc.xref.Part1.34"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>).
    2114       </p>
    2115       <div class="note" id="rfc.section.9.8.p.7">
    2116          <p> <b>Note:</b> Revealing the specific software version of the server might allow the server machine to become more vulnerable to attacks
    2117             against software that is known to contain security holes. Server implementors are encouraged to make this field a configurable
    2118             option.
    2119          </p>
     2293            </p>
     2294            <div class="note" id="rfc.section.9.8.p.7">
     2295               <p><b>Note:</b> Revealing the specific software version of the server might allow the server machine to become more vulnerable to attacks
     2296                  against software that is known to contain security holes. Server implementors are encouraged to make this field a configurable
     2297                  option.
     2298               </p>
     2299            </div>
     2300         </div>
     2301         <div id="header.user-agent">
     2302            <div id="rfc.iref.u.1"></div>
     2303            <div id="rfc.iref.h.10"></div>
     2304            <h2 id="rfc.section.9.9"><a href="#rfc.section.9.9">9.9</a>&nbsp;<a href="#header.user-agent">User-Agent</a></h2>
     2305            <p id="rfc.section.9.9.p.1">The "User-Agent" header field contains information about the user agent originating the request. User agents <em class="bcp14">SHOULD</em> include this field with requests.
     2306            </p>
     2307            <p id="rfc.section.9.9.p.2">Typically, it is used for statistical purposes, the tracing of protocol violations, and tailoring responses to avoid particular
     2308               user agent limitations.
     2309            </p>
     2310            <p id="rfc.section.9.9.p.3">The field can contain multiple product tokens (<a href="p1-messaging.html#product.tokens" title="Product Tokens">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1.35"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.36"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance
     2311               for identifying the application.
     2312            </p>
     2313            <p id="rfc.section.9.9.p.4">Because this field is usually sent on every request a user agent makes, implementations are encouraged not to include needlessly
     2314               fine-grained detail, and to limit (or even prohibit) the addition of subproducts by third parties. Overly long and detailed
     2315               User-Agent field values make requests larger and can also be used to identify ("fingerprint") the user against their wishes.
     2316            </p>
     2317            <p id="rfc.section.9.9.p.5">Likewise, implementations are encouraged not to use the product tokens of other implementations in order to declare compatibility
     2318               with them, as this circumvents the purpose of the field. Finally, they are encouraged not to use comments to identify products;
     2319               doing so makes the field value more difficult to parse.
     2320            </p>
     2321            <div id="rfc.figure.u.24"></div><pre class="inline"><span id="rfc.iref.g.18"></span>  <a href="#header.user-agent" class="smpl">User-Agent</a> = <a href="#abnf.dependencies" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#abnf.dependencies" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
     2322</pre><p id="rfc.section.9.9.p.7">Example:</p>
     2323            <div id="rfc.figure.u.25"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
     2324</pre></div>
    21202325      </div>
    2121       <div id="rfc.iref.u.1"></div>
    2122       <div id="rfc.iref.h.10"></div>
    2123       <h2 id="rfc.section.9.9"><a href="#rfc.section.9.9">9.9</a>&nbsp;<a id="header.user-agent" href="#header.user-agent">User-Agent</a></h2>
    2124       <p id="rfc.section.9.9.p.1">The "User-Agent" header field contains information about the user agent originating the request. User agents <em class="bcp14">SHOULD</em> include this field with requests.
    2125       </p>
    2126       <p id="rfc.section.9.9.p.2">Typically, it is used for statistical purposes, the tracing of protocol violations, and tailoring responses to avoid particular
    2127          user agent limitations.
    2128       </p>
    2129       <p id="rfc.section.9.9.p.3">The field can contain multiple product tokens (<a href="p1-messaging.html#product.tokens" title="Product Tokens">Section 6.3</a> of <a href="#Part1" id="rfc.xref.Part1.35"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) and comments (<a href="p1-messaging.html#header.fields" title="Header Fields">Section 3.2</a> of <a href="#Part1" id="rfc.xref.Part1.36"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) identifying the agent and its significant subproducts. By convention, the product tokens are listed in order of their significance
    2130          for identifying the application.
    2131       </p>
    2132       <p id="rfc.section.9.9.p.4">Because this field is usually sent on every request a user agent makes, implementations are encouraged not to include needlessly
    2133          fine-grained detail, and to limit (or even prohibit) the addition of subproducts by third parties. Overly long and detailed
    2134          User-Agent field values make requests larger and can also be used to identify ("fingerprint") the user against their wishes.
    2135       </p>
    2136       <p id="rfc.section.9.9.p.5">Likewise, implementations are encouraged not to use the product tokens of other implementations in order to declare compatibility
    2137          with them, as this circumvents the purpose of the field. Finally, they are encouraged not to use comments to identify products;
    2138          doing so makes the field value more difficult to parse.
    2139       </p>
    2140       <div id="rfc.figure.u.24"></div><pre class="inline"><span id="rfc.iref.g.18"></span>  <a href="#header.user-agent" class="smpl">User-Agent</a> = <a href="#abnf.dependencies" class="smpl">product</a> *( <a href="#core.rules" class="smpl">RWS</a> ( <a href="#abnf.dependencies" class="smpl">product</a> / <a href="#abnf.dependencies" class="smpl">comment</a> ) )
    2141 </pre><p id="rfc.section.9.9.p.7">Example:</p>
    2142       <div id="rfc.figure.u.25"></div><pre class="text">  User-Agent: CERN-LineMode/2.15 libwww/2.17b3
    2143 </pre><h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a>&nbsp;<a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>
    2144       <h2 id="rfc.section.10.1"><a href="#rfc.section.10.1">10.1</a>&nbsp;<a id="method.registration" href="#method.registration">Method Registry</a></h2>
    2145       <p id="rfc.section.10.1.p.1">The registration procedure for HTTP request methods is defined by <a href="#method.registry" title="Method Registry">Section&nbsp;2.2</a> of this document.
    2146       </p>
    2147       <p id="rfc.section.10.1.p.2">The HTTP Method Registry shall be created at &lt;<a href="http://www.iana.org/assignments/http-methods">http://www.iana.org/assignments/http-methods</a>&gt; and be populated with the registrations below:
    2148       </p>
    2149       <div id="rfc.table.1">
    2150          <div id="iana.method.registration.table"></div>
    2151          <table class="tt full left" cellpadding="3" cellspacing="0">
    2152             <thead>
    2153                <tr>
    2154                   <th>Method</th>
    2155                   <th>Safe</th>
    2156                   <th>Reference</th>
    2157                </tr>
    2158             </thead>
    2159             <tbody>
    2160                <tr>
    2161                   <td class="left">CONNECT</td>
    2162                   <td class="left">no</td>
    2163                   <td class="left"> <a href="#CONNECT" id="rfc.xref.CONNECT.2" title="CONNECT">Section&nbsp;7.9</a>
    2164                   </td>
    2165                </tr>
    2166                <tr>
    2167                   <td class="left">DELETE</td>
    2168                   <td class="left">no</td>
    2169                   <td class="left"> <a href="#DELETE" id="rfc.xref.DELETE.2" title="DELETE">Section&nbsp;7.7</a>
    2170                   </td>
    2171                </tr>
    2172                <tr>
    2173                   <td class="left">GET</td>
    2174                   <td class="left">yes</td>
    2175                   <td class="left"> <a href="#GET" id="rfc.xref.GET.2" title="GET">Section&nbsp;7.3</a>
    2176                   </td>
    2177                </tr>
    2178                <tr>
    2179                   <td class="left">HEAD</td>
    2180                   <td class="left">yes</td>
    2181                   <td class="left"> <a href="#HEAD" id="rfc.xref.HEAD.2" title="HEAD">Section&nbsp;7.4</a>
    2182                   </td>
    2183                </tr>
    2184                <tr>
    2185                   <td class="left">OPTIONS</td>
    2186                   <td class="left">yes</td>
    2187                   <td class="left"> <a href="#OPTIONS" id="rfc.xref.OPTIONS.3" title="OPTIONS">Section&nbsp;7.2</a>
    2188                   </td>
    2189                </tr>
    2190                <tr>
    2191                   <td class="left">POST</td>
    2192                   <td class="left">no</td>
    2193                   <td class="left"> <a href="#POST" id="rfc.xref.POST.2" title="POST">Section&nbsp;7.5</a>
    2194                   </td>
    2195                </tr>
    2196                <tr>
    2197                   <td class="left">PUT</td>
    2198                   <td class="left">no</td>
    2199                   <td class="left"> <a href="#PUT" id="rfc.xref.PUT.2" title="PUT">Section&nbsp;7.6</a>
    2200                   </td>
    2201                </tr>
    2202                <tr>
    2203                   <td class="left">TRACE</td>
    2204                   <td class="left">yes</td>
    2205                   <td class="left"> <a href="#TRACE" id="rfc.xref.TRACE.3" title="TRACE">Section&nbsp;7.8</a>
    2206                   </td>
    2207                </tr>
    2208             </tbody>
    2209          </table>
     2326      <div id="IANA.considerations">
     2327         <h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a>&nbsp;<a href="#IANA.considerations">IANA Considerations</a></h1>
     2328         <div id="method.registration">
     2329            <h2 id="rfc.section.10.1"><a href="#rfc.section.10.1">10.1</a>&nbsp;<a href="#method.registration">Method Registry</a></h2>
     2330            <p id="rfc.section.10.1.p.1">The registration procedure for HTTP request methods is defined by <a href="#method.registry" title="Method Registry">Section&nbsp;2.2</a> of this document.
     2331            </p>
     2332            <p id="rfc.section.10.1.p.2">The HTTP Method Registry shall be created at &lt;<a href="http://www.iana.org/assignments/http-methods">http://www.iana.org/assignments/http-methods</a>&gt; and be populated with the registrations below:
     2333            </p>
     2334            <div id="rfc.table.1">
     2335               <div id="iana.method.registration.table"></div>
     2336               <table class="tt full left" cellpadding="3" cellspacing="0">
     2337                  <thead>
     2338                     <tr>
     2339                        <th>Method</th>
     2340                        <th>Safe</th>
     2341                        <th>Reference</th>
     2342                     </tr>
     2343                  </thead>
     2344                  <tbody>
     2345                     <tr>
     2346                        <td class="left">CONNECT</td>
     2347                        <td class="left">no</td>
     2348                        <td class="left"><a href="#CONNECT" id="rfc.xref.CONNECT.2" title="CONNECT">Section&nbsp;7.9</a>
     2349                        </td>
     2350                     </tr>
     2351                     <tr>
     2352                        <td class="left">DELETE</td>
     2353                        <td class="left">no</td>
     2354                        <td class="left"><a href="#DELETE" id="rfc.xref.DELETE.2" title="DELETE">Section&nbsp;7.7</a>
     2355                        </td>
     2356                     </tr>
     2357                     <tr>
     2358                        <td class="left">GET</td>
     2359                        <td class="left">yes</td>
     2360                        <td class="left"><a href="#GET" id="rfc.xref.GET.2" title="GET">Section&nbsp;7.3</a>
     2361                        </td>
     2362                     </tr>
     2363                     <tr>
     2364                        <td class="left">HEAD</td>
     2365                        <td class="left">yes</td>
     2366                        <td class="left"><a href="#HEAD" id="rfc.xref.HEAD.2" title="HEAD">Section&nbsp;7.4</a>
     2367                        </td>
     2368                     </tr>
     2369                     <tr>
     2370                        <td class="left">OPTIONS</td>
     2371                        <td class="left">yes</td>
     2372                        <td class="left"><a href="#OPTIONS" id="rfc.xref.OPTIONS.3" title="OPTIONS">Section&nbsp;7.2</a>
     2373                        </td>
     2374                     </tr>
     2375                     <tr>
     2376                        <td class="left">POST</td>
     2377                        <td class="left">no</td>
     2378                        <td class="left"><a href="#POST" id="rfc.xref.POST.2" title="POST">Section&nbsp;7.5</a>
     2379                        </td>
     2380                     </tr>
     2381                     <tr>
     2382                        <td class="left">PUT</td>
     2383                        <td class="left">no</td>
     2384                        <td class="left"><a href="#PUT" id="rfc.xref.PUT.2" title="PUT">Section&nbsp;7.6</a>
     2385                        </td>
     2386                     </tr>
     2387                     <tr>
     2388                        <td class="left">TRACE</td>
     2389                        <td class="left">yes</td>
     2390                        <td class="left"><a href="#TRACE" id="rfc.xref.TRACE.3" title="TRACE">Section&nbsp;7.8</a>
     2391                        </td>
     2392                     </tr>
     2393                  </tbody>
     2394               </table>
     2395            </div>
     2396         </div>
     2397         <div id="status.code.registration">
     2398            <h2 id="rfc.section.10.2"><a href="#rfc.section.10.2">10.2</a>&nbsp;<a href="#status.code.registration">Status Code Registry</a></h2>
     2399            <p id="rfc.section.10.2.p.1">The registration procedure for HTTP Status Codes — previously defined in <a href="https://tools.ietf.org/html/rfc2817#section-7.1">Section 7.1</a> of <a href="#RFC2817" id="rfc.xref.RFC2817.1"><cite title="Upgrading to TLS Within HTTP/1.1">[RFC2817]</cite></a> — is now defined by <a href="#status.code.registry" title="Status Code Registry">Section&nbsp;4.2</a> of this document.
     2400            </p>
     2401            <p id="rfc.section.10.2.p.2">The HTTP Status Code Registry located at &lt;<a href="http://www.iana.org/assignments/http-status-codes">http://www.iana.org/assignments/http-status-codes</a>&gt; shall be updated with the registrations below:
     2402            </p>
     2403            <div id="rfc.table.2">
     2404               <div id="iana.status.code.registration.table"></div>
     2405               <table class="tt full left" cellpadding="3" cellspacing="0">
     2406                  <thead>
     2407                     <tr>
     2408                        <th>Value</th>
     2409                        <th>Description</th>
     2410                        <th>Reference</th>
     2411                     </tr>
     2412                  </thead>
     2413                  <tbody>
     2414                     <tr>
     2415                        <td class="left">100</td>
     2416                        <td class="left">Continue</td>
     2417                        <td class="left"><a href="#status.100" id="rfc.xref.status.100.2" title="100 Continue">Section&nbsp;8.1.1</a>
     2418                        </td>
     2419                     </tr>
     2420                     <tr>
     2421                        <td class="left">101</td>
     2422                        <td class="left">Switching Protocols</td>
     2423                        <td class="left"><a href="#status.101" id="rfc.xref.status.101.2" title="101 Switching Protocols">Section&nbsp;8.1.2</a>
     2424                        </td>
     2425                     </tr>
     2426                     <tr>
     2427                        <td class="left">200</td>
     2428                        <td class="left">OK</td>
     2429                        <td class="left"><a href="#status.200" id="rfc.xref.status.200.2" title="200 OK">Section&nbsp;8.2.1</a>
     2430                        </td>
     2431                     </tr>
     2432                     <tr>
     2433                        <td class="left">201</td>
     2434                        <td class="left">Created</td>
     2435                        <td class="left"><a href="#status.201" id="rfc.xref.status.201.2" title="201 Created">Section&nbsp;8.2.2</a>
     2436                        </td>
     2437                     </tr>
     2438                     <tr>
     2439                        <td class="left">202</td>
     2440                        <td class="left">Accepted</td>
     2441                        <td class="left"><a href="#status.202" id="rfc.xref.status.202.2" title="202 Accepted">Section&nbsp;8.2.3</a>
     2442                        </td>
     2443                     </tr>
     2444                     <tr>
     2445                        <td class="left">203</td>
     2446                        <td class="left">Non-Authoritative Information</td>
     2447                        <td class="left"><a href="#status.203" id="rfc.xref.status.203.2" title="203 Non-Authoritative Information">Section&nbsp;8.2.4</a>
     2448                        </td>
     2449                     </tr>
     2450                     <tr>
     2451                        <td class="left">204</td>
     2452                        <td class="left">No Content</td>
     2453                        <td class="left"><a href="#status.204" id="rfc.xref.status.204.2" title="204 No Content">Section&nbsp;8.2.5</a>
     2454                        </td>
     2455                     </tr>
     2456                     <tr>
     2457                        <td class="left">205</td>
     2458                        <td class="left">Reset Content</td>
     2459                        <td class="left"><a href="#status.205" id="rfc.xref.status.205.2" title="205 Reset Content">Section&nbsp;8.2.6</a>
     2460                        </td>
     2461                     </tr>
     2462                     <tr>
     2463                        <td class="left">300</td>
     2464                        <td class="left">Multiple Choices</td>
     2465                        <td class="left"><a href="#status.300" id="rfc.xref.status.300.2" title="300 Multiple Choices">Section&nbsp;8.3.1</a>
     2466                        </td>
     2467                     </tr>
     2468                     <tr>
     2469                        <td class="left">301</td>
     2470                        <td class="left">Moved Permanently</td>
     2471                        <td class="left"><a href="#status.301" id="rfc.xref.status.301.2" title="301 Moved Permanently">Section&nbsp;8.3.2</a>
     2472                        </td>
     2473                     </tr>
     2474                     <tr>
     2475                        <td class="left">302</td>
     2476                        <td class="left">Found</td>
     2477                        <td class="left"><a href="#status.302" id="rfc.xref.status.302.2" title="302 Found">Section&nbsp;8.3.3</a>
     2478                        </td>
     2479                     </tr>
     2480                     <tr>
     2481                        <td class="left">303</td>
     2482                        <td class="left">See Other</td>
     2483                        <td class="left"><a href="#status.303" id="rfc.xref.status.303.3" title="303 See Other">Section&nbsp;8.3.4</a>
     2484                        </td>
     2485                     </tr>
     2486                     <tr>
     2487                        <td class="left">305</td>
     2488                        <td class="left">Use Proxy</td>
     2489                        <td class="left"><a href="#status.305" id="rfc.xref.status.305.2" title="305 Use Proxy">Section&nbsp;8.3.6</a>
     2490                        </td>
     2491                     </tr>
     2492                     <tr>
     2493                        <td class="left">306</td>
     2494                        <td class="left">(Unused)</td>
     2495                        <td class="left"><a href="#status.306" id="rfc.xref.status.306.1" title="306 (Unused)">Section&nbsp;8.3.7</a>
     2496                        </td>
     2497                     </tr>
     2498                     <tr>
     2499                        <td class="left">307</td>
     2500                        <td class="left">Temporary Redirect</td>
     2501                        <td class="left"><a href="#status.307" id="rfc.xref.status.307.3" title="307 Temporary Redirect">Section&nbsp;8.3.8</a>
     2502                        </td>
     2503                     </tr>
     2504                     <tr>
     2505                        <td class="left">400</td>
     2506                        <td class="left">Bad Request</td>
     2507                        <td class="left"><a href="#status.400" id="rfc.xref.status.400.2" title="400 Bad Request">Section&nbsp;8.4.1</a>
     2508                        </td>
     2509                     </tr>
     2510                     <tr>
     2511                        <td class="left">402</td>
     2512                        <td class="left">Payment Required</td>
     2513                        <td class="left"><a href="#status.402" id="rfc.xref.status.402.2" title="402 Payment Required">Section&nbsp;8.4.3</a>
     2514                        </td>
     2515                     </tr>
     2516                     <tr>
     2517                        <td class="left">403</td>
     2518                        <td class="left">Forbidden</td>
     2519                        <td class="left"><a href="#status.403" id="rfc.xref.status.403.2" title="403 Forbidden">Section&nbsp;8.4.4</a>
     2520                        </td>
     2521                     </tr>
     2522                     <tr>
     2523                        <td class="left">404</td>
     2524                        <td class="left">Not Found</td>
     2525                        <td class="left"><a href="#status.404" id="rfc.xref.status.404.2" title="404 Not Found">Section&nbsp;8.4.5</a>
     2526                        </td>
     2527                     </tr>
     2528                     <tr>
     2529                        <td class="left">405</td>
     2530                        <td class="left">Method Not Allowed</td>
     2531                        <td class="left"><a href="#status.405" id="rfc.xref.status.405.2" title="405 Method Not Allowed">Section&nbsp;8.4.6</a>
     2532                        </td>
     2533                     </tr>
     2534                     <tr>
     2535                        <td class="left">406</td>
     2536                        <td class="left">Not Acceptable</td>
     2537                        <td class="left"><a href="#status.406" id="rfc.xref.status.406.2" title="406 Not Acceptable">Section&nbsp;8.4.7</a>
     2538                        </td>
     2539                     </tr>
     2540                     <tr>
     2541                        <td class="left">407</td>
     2542                        <td class="left">Proxy Authentication Required</td>
     2543                        <td class="left"><a href="#status.407" id="rfc.xref.status.407.1" title="407 Proxy Authentication Required">Section&nbsp;8.4.8</a>
     2544                        </td>
     2545                     </tr>
     2546                     <tr>
     2547                        <td class="left">408</td>
     2548                        <td class="left">Request Timeout</td>
     2549                        <td class="left"><a href="#status.408" id="rfc.xref.status.408.2" title="408 Request Timeout">Section&nbsp;8.4.9</a>
     2550                        </td>
     2551                     </tr>
     2552                     <tr>
     2553                        <td class="left">409</td>
     2554                        <td class="left">Conflict</td>
     2555                        <td class="left"><a href="#status.409" id="rfc.xref.status.409.2" title="409 Conflict">Section&nbsp;8.4.10</a>
     2556                        </td>
     2557                     </tr>
     2558                     <tr>
     2559                        <td class="left">410</td>
     2560                        <td class="left">Gone</td>
     2561                        <td class="left"><a href="#status.410" id="rfc.xref.status.410.2" title="410 Gone">Section&nbsp;8.4.11</a>
     2562                        </td>
     2563                     </tr>
     2564                     <tr>
     2565                        <td class="left">411</td>
     2566                        <td class="left">Length Required</td>
     2567                        <td class="left"><a href="#status.411" id="rfc.xref.status.411.2" title="411 Length Required">Section&nbsp;8.4.12</a>
     2568                        </td>
     2569                     </tr>
     2570                     <tr>
     2571                        <td class="left">413</td>
     2572                        <td class="left">Request Representation Too Large</td>
     2573                        <td class="left"><a href="#status.413" id="rfc.xref.status.413.2" title="413 Request Representation Too Large">Section&nbsp;8.4.14</a>
     2574                        </td>
     2575                     </tr>
     2576                     <tr>
     2577                        <td class="left">414</td>
     2578                        <td class="left">URI Too Long</td>
     2579                        <td class="left"><a href="#status.414" id="rfc.xref.status.414.2" title="414 URI Too Long">Section&nbsp;8.4.15</a>
     2580                        </td>
     2581                     </tr>
     2582                     <tr>
     2583                        <td class="left">415</td>
     2584                        <td class="left">Unsupported Media Type</td>
     2585                        <td class="left"><a href="#status.415" id="rfc.xref.status.415.2" title="415 Unsupported Media Type">Section&nbsp;8.4.16</a>
     2586                        </td>
     2587                     </tr>
     2588                     <tr>
     2589                        <td class="left">417</td>
     2590                        <td class="left">Expectation Failed</td>
     2591                        <td class="left"><a href="#status.417" id="rfc.xref.status.417.2" title="417 Expectation Failed">Section&nbsp;8.4.18</a>
     2592                        </td>
     2593                     </tr>
     2594                     <tr>
     2595                        <td class="left">426</td>
     2596                        <td class="left">Upgrade Required</td>
     2597                        <td class="left"><a href="#status.426" id="rfc.xref.status.426.2" title="426 Upgrade Required">Section&nbsp;8.4.19</a>
     2598                        </td>
     2599                     </tr>
     2600                     <tr>
     2601                        <td class="left">500</td>
     2602                        <td class="left">Internal Server Error</td>
     2603                        <td class="left"><a href="#status.500" id="rfc.xref.status.500.2" title="500 Internal Server Error">Section&nbsp;8.5.1</a>
     2604                        </td>
     2605                     </tr>
     2606                     <tr>
     2607                        <td class="left">501</td>
     2608                        <td class="left">Not Implemented</td>
     2609                        <td class="left"><a href="#status.501" id="rfc.xref.status.501.2" title="501 Not Implemented">Section&nbsp;8.5.2</a>
     2610                        </td>
     2611                     </tr>
     2612                     <tr>
     2613                        <td class="left">502</td>
     2614                        <td class="left">Bad Gateway</td>
     2615                        <td class="left"><a href="#status.502" id="rfc.xref.status.502.2" title="502 Bad Gateway">Section&nbsp;8.5.3</a>
     2616                        </td>
     2617                     </tr>
     2618                     <tr>
     2619                        <td class="left">503</td>
     2620                        <td class="left">Service Unavailable</td>
     2621                        <td class="left"><a href="#status.503" id="rfc.xref.status.503.2" title="503 Service Unavailable">Section&nbsp;8.5.4</a>
     2622                        </td>
     2623                     </tr>
     2624                     <tr>
     2625                        <td class="left">504</td>
     2626                        <td class="left">Gateway Timeout</td>
     2627                        <td class="left"><a href="#status.504" id="rfc.xref.status.504.2" title="504 Gateway Timeout">Section&nbsp;8.5.5</a>
     2628                        </td>
     2629                     </tr>
     2630                     <tr>
     2631                        <td class="left">505</td>
     2632                        <td class="left">HTTP Version Not Supported</td>
     2633                        <td class="left"><a href="#status.505" id="rfc.xref.status.505.2" title="505 HTTP Version Not Supported">Section&nbsp;8.5.6</a>
     2634                        </td>
     2635                     </tr>
     2636                  </tbody>
     2637               </table>
     2638            </div>
     2639         </div>
     2640         <div id="header.field.registration">
     2641            <h2 id="rfc.section.10.3"><a href="#rfc.section.10.3">10.3</a>&nbsp;<a href="#header.field.registration">Header Field Registration</a></h2>
     2642            <p id="rfc.section.10.3.p.1">The Message Header Field Registry located at &lt;<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>&gt; shall be updated with the permanent registrations below (see <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>):
     2643            </p>
     2644            <div id="rfc.table.3">
     2645               <div id="iana.header.registration.table"></div>
     2646               <table class="tt full left" cellpadding="3" cellspacing="0">
     2647                  <thead>
     2648                     <tr>
     2649                        <th>Header Field Name</th>
     2650                        <th>Protocol</th>
     2651                        <th>Status</th>
     2652                        <th>Reference</th>