Changeset 651
- Timestamp:
- 29/07/09 09:21:28 (13 years ago)
- Location:
- draft-ietf-httpbis/latest
- Files:
-
- 2 edited
Legend:
- Unmodified
- Added
- Removed
-
draft-ietf-httpbis/latest/p1-messaging.html
r649 r651 360 360 <link rel="Chapter" title="1 Introduction" href="#rfc.section.1"> 361 361 <link rel="Chapter" title="2 HTTP architecture" href="#rfc.section.2"> 362 <link rel="Chapter" title="3 HTTP Message" href="#rfc.section.3"> 363 <link rel="Chapter" title="4 Request" href="#rfc.section.4"> 364 <link rel="Chapter" title="5 Response" href="#rfc.section.5"> 365 <link rel="Chapter" title="6 Protocol Parameters" href="#rfc.section.6"> 366 <link rel="Chapter" title="7 Connections" href="#rfc.section.7"> 367 <link rel="Chapter" title="8 Header Field Definitions" href="#rfc.section.8"> 368 <link rel="Chapter" title="9 IANA Considerations" href="#rfc.section.9"> 369 <link rel="Chapter" title="10 Security Considerations" href="#rfc.section.10"> 370 <link rel="Chapter" title="11 Acknowledgments" href="#rfc.section.11"> 371 <link rel="Chapter" href="#rfc.section.12" title="12 References"> 362 <link rel="Chapter" title="3 Header Field Definitions" href="#rfc.section.3"> 363 <link rel="Chapter" title="4 IANA Considerations" href="#rfc.section.4"> 364 <link rel="Chapter" title="5 Security Considerations" href="#rfc.section.5"> 365 <link rel="Chapter" title="6 Acknowledgments" href="#rfc.section.6"> 366 <link rel="Chapter" href="#rfc.section.7" title="7 References"> 372 367 <link rel="Appendix" title="A Tolerant Applications" href="#rfc.section.A"> 373 368 <link rel="Appendix" title="B Compatibility with Previous Versions" href="#rfc.section.B"> … … 471 466 <tr> 472 467 <td class="header left"></td> 473 <td class="header right">July 2 8, 2009</td>468 <td class="header right">July 29, 2009</td> 474 469 </tr> 475 470 </table> … … 538 533 <li class="tocline1">2.6.2 <a href="#https.uri">https URI scheme</a></li> 539 534 <li class="tocline1">2.6.3 <a href="#uri.comparison">http and https URI Normalization and Comparison</a></li> 540 <li class="tocline1">2.6.4 <a href="#scheme.aliases">Scheme aliases considered harmful</a></li>541 535 </ul> 542 536 </li> 543 <li class="tocline1">2.7 <a href="#http.proxy">Use of HTTP for proxy communication</a></li> 544 <li class="tocline1">2.8 <a href="#http.intercept">Interception of HTTP for access control</a></li> 545 <li class="tocline1">2.9 <a href="#http.others">Use of HTTP by other protocols</a></li> 546 <li class="tocline1">2.10 <a href="#http.media">Use of HTTP by media type specification</a></li> 547 </ul> 548 </li> 549 <li class="tocline0">3. <a href="#http.message">HTTP Message</a><ul class="toc"> 550 <li class="tocline1">3.1 <a href="#message.robustness">Message Parsing Robustness</a></li> 551 <li class="tocline1">3.2 <a href="#header.fields">Header Fields</a></li> 552 <li class="tocline1">3.3 <a href="#message.body">Message Body</a></li> 553 <li class="tocline1">3.4 <a href="#message.length">Message Length</a></li> 554 <li class="tocline1">3.5 <a href="#general.header.fields">General Header Fields</a></li> 555 </ul> 556 </li> 557 <li class="tocline0">4. <a href="#request">Request</a><ul class="toc"> 558 <li class="tocline1">4.1 <a href="#request-line">Request-Line</a><ul class="toc"> 559 <li class="tocline1">4.1.1 <a href="#method">Method</a></li> 560 <li class="tocline1">4.1.2 <a href="#request-target">request-target</a></li> 537 <li class="tocline1">2.7 <a href="#http.message">HTTP Message</a><ul class="toc"> 538 <li class="tocline1">2.7.1 <a href="#message.robustness">Message Parsing Robustness</a></li> 539 <li class="tocline1">2.7.2 <a href="#header.fields">Header Fields</a></li> 540 <li class="tocline1">2.7.3 <a href="#message.body">Message Body</a></li> 541 <li class="tocline1">2.7.4 <a href="#message.length">Message Length</a></li> 542 <li class="tocline1">2.7.5 <a href="#general.header.fields">General Header Fields</a></li> 561 543 </ul> 562 544 </li> 563 <li class="tocline1">4.2 <a href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></li> 564 </ul> 565 </li> 566 <li class="tocline0">5. <a href="#response">Response</a><ul class="toc"> 567 <li class="tocline1">5.1 <a href="#status-line">Status-Line</a><ul class="toc"> 568 <li class="tocline1">5.1.1 <a href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></li> 545 <li class="tocline1">2.8 <a href="#request">Request</a><ul class="toc"> 546 <li class="tocline1">2.8.1 <a href="#request-line">Request-Line</a><ul class="toc"> 547 <li class="tocline1">2.8.1.1 <a href="#method">Method</a></li> 548 <li class="tocline1">2.8.1.2 <a href="#request-target">request-target</a></li> 549 </ul> 550 </li> 551 <li class="tocline1">2.8.2 <a href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></li> 569 552 </ul> 570 553 </li> 571 </ul> 572 </li> 573 <li class="tocline0">6. <a href="#protocol.parameters">Protocol Parameters</a><ul class="toc"> 574 <li class="tocline1">6.1 <a href="#date.time.formats.full.date">Date/Time Formats: Full Date</a></li> 575 <li class="tocline1">6.2 <a href="#transfer.codings">Transfer Codings</a><ul class="toc"> 576 <li class="tocline1">6.2.1 <a href="#chunked.transfer.encoding">Chunked Transfer Coding</a></li> 554 <li class="tocline1">2.9 <a href="#response">Response</a><ul class="toc"> 555 <li class="tocline1">2.9.1 <a href="#status-line">Status-Line</a><ul class="toc"> 556 <li class="tocline1">2.9.1.1 <a href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></li> 557 </ul> 558 </li> 577 559 </ul> 578 560 </li> 579 <li class="tocline1">6.3 <a href="#product.tokens">Product Tokens</a></li> 580 <li class="tocline1">6.4 <a href="#quality.values">Quality Values</a></li> 581 </ul> 582 </li> 583 <li class="tocline0">7. <a href="#connections">Connections</a><ul class="toc"> 584 <li class="tocline1">7.1 <a href="#persistent.connections">Persistent Connections</a><ul class="toc"> 585 <li class="tocline1">7.1.1 <a href="#persistent.purpose">Purpose</a></li> 586 <li class="tocline1">7.1.2 <a href="#persistent.overall">Overall Operation</a><ul class="toc"> 587 <li class="tocline1">7.1.2.1 <a href="#persistent.negotiation">Negotiation</a></li> 588 <li class="tocline1">7.1.2.2 <a href="#pipelining">Pipelining</a></li> 561 <li class="tocline1">2.10 <a href="#protocol.parameters">Protocol Parameters</a><ul class="toc"> 562 <li class="tocline1">2.10.1 <a href="#date.time.formats.full.date">Date/Time Formats: Full Date</a></li> 563 <li class="tocline1">2.10.2 <a href="#transfer.codings">Transfer Codings</a><ul class="toc"> 564 <li class="tocline1">2.10.2.1 <a href="#chunked.transfer.encoding">Chunked Transfer Coding</a></li> 589 565 </ul> 590 566 </li> 591 <li class="tocline1"> 7.1.3 <a href="#persistent.proxy">Proxy Servers</a></li>592 <li class="tocline1"> 7.1.4 <a href="#persistent.practical">Practical Considerations</a></li>567 <li class="tocline1">2.10.3 <a href="#product.tokens">Product Tokens</a></li> 568 <li class="tocline1">2.10.4 <a href="#quality.values">Quality Values</a></li> 593 569 </ul> 594 570 </li> 595 <li class="tocline1">7.2 <a href="#message.transmission.requirements">Message Transmission Requirements</a><ul class="toc"> 596 <li class="tocline1">7.2.1 <a href="#persistent.flow">Persistent Connections and Flow Control</a></li> 597 <li class="tocline1">7.2.2 <a href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></li> 598 <li class="tocline1">7.2.3 <a href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></li> 599 <li class="tocline1">7.2.4 <a href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></li> 571 <li class="tocline1">2.11 <a href="#connections">Connections</a><ul class="toc"> 572 <li class="tocline1">2.11.1 <a href="#persistent.connections">Persistent Connections</a><ul class="toc"> 573 <li class="tocline1">2.11.1.1 <a href="#persistent.purpose">Purpose</a></li> 574 <li class="tocline1">2.11.1.2 <a href="#persistent.overall">Overall Operation</a><ul class="toc"> 575 <li class="tocline1">2.11.1.2.1 <a href="#persistent.negotiation">Negotiation</a></li> 576 <li class="tocline1">2.11.1.2.2 <a href="#pipelining">Pipelining</a></li> 577 </ul> 578 </li> 579 <li class="tocline1">2.11.1.3 <a href="#persistent.proxy">Proxy Servers</a></li> 580 <li class="tocline1">2.11.1.4 <a href="#persistent.practical">Practical Considerations</a></li> 581 </ul> 582 </li> 583 <li class="tocline1">2.11.2 <a href="#message.transmission.requirements">Message Transmission Requirements</a><ul class="toc"> 584 <li class="tocline1">2.11.2.1 <a href="#persistent.flow">Persistent Connections and Flow Control</a></li> 585 <li class="tocline1">2.11.2.2 <a href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></li> 586 <li class="tocline1">2.11.2.3 <a href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></li> 587 <li class="tocline1">2.11.2.4 <a href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></li> 588 </ul> 589 </li> 600 590 </ul> 601 591 </li> 602 </ul> 603 </li> 604 <li class="tocline0">8. <a href="#header.field.definitions">Header Field Definitions</a><ul class="toc"> 605 <li class="tocline1">8.1 <a href="#header.connection">Connection</a></li> 606 <li class="tocline1">8.2 <a href="#header.content-length">Content-Length</a></li> 607 <li class="tocline1">8.3 <a href="#header.date">Date</a><ul class="toc"> 608 <li class="tocline1">8.3.1 <a href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></li> 592 <li class="tocline1">2.12 <a href="#misc">Miscellaneous notes that may disappear</a><ul class="toc"> 593 <li class="tocline1">2.12.1 <a href="#scheme.aliases">Scheme aliases considered harmful</a></li> 609 594 </ul> 610 595 </li> 611 <li class="tocline1">8.4 <a href="#header.host">Host</a></li> 612 <li class="tocline1">8.5 <a href="#header.te">TE</a></li> 613 <li class="tocline1">8.6 <a href="#header.trailer">Trailer</a></li> 614 <li class="tocline1">8.7 <a href="#header.transfer-encoding">Transfer-Encoding</a></li> 615 <li class="tocline1">8.8 <a href="#header.upgrade">Upgrade</a></li> 616 <li class="tocline1">8.9 <a href="#header.via">Via</a></li> 596 <li class="tocline1">2.13 <a href="#http.proxy">Use of HTTP for proxy communication</a></li> 597 <li class="tocline1">2.14 <a href="#http.intercept">Interception of HTTP for access control</a></li> 598 <li class="tocline1">2.15 <a href="#http.others">Use of HTTP by other protocols</a></li> 599 <li class="tocline1">2.16 <a href="#http.media">Use of HTTP by media type specification</a></li> 617 600 </ul> 618 601 </li> 619 <li class="tocline0">9. <a href="#IANA.considerations">IANA Considerations</a><ul class="toc"> 620 <li class="tocline1">9.1 <a href="#message.header.registration">Message Header Registration</a></li> 621 <li class="tocline1">9.2 <a href="#uri.scheme.registration">URI Scheme Registration</a></li> 622 <li class="tocline1">9.3 <a href="#internet.media.type.http">Internet Media Type Registrations</a><ul class="toc"> 623 <li class="tocline1">9.3.1 <a href="#internet.media.type.message.http">Internet Media Type message/http</a></li> 624 <li class="tocline1">9.3.2 <a href="#internet.media.type.application.http">Internet Media Type application/http</a></li> 602 <li class="tocline0">3. <a href="#header.field.definitions">Header Field Definitions</a><ul class="toc"> 603 <li class="tocline1">3.1 <a href="#header.connection">Connection</a></li> 604 <li class="tocline1">3.2 <a href="#header.content-length">Content-Length</a></li> 605 <li class="tocline1">3.3 <a href="#header.date">Date</a><ul class="toc"> 606 <li class="tocline1">3.3.1 <a href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></li> 625 607 </ul> 626 608 </li> 609 <li class="tocline1">3.4 <a href="#header.host">Host</a></li> 610 <li class="tocline1">3.5 <a href="#header.te">TE</a></li> 611 <li class="tocline1">3.6 <a href="#header.trailer">Trailer</a></li> 612 <li class="tocline1">3.7 <a href="#header.transfer-encoding">Transfer-Encoding</a></li> 613 <li class="tocline1">3.8 <a href="#header.upgrade">Upgrade</a></li> 614 <li class="tocline1">3.9 <a href="#header.via">Via</a></li> 627 615 </ul> 628 616 </li> 629 <li class="tocline0">10. <a href="#security.considerations">Security Considerations</a><ul class="toc"> 630 <li class="tocline1">10.1 <a href="#personal.information">Personal Information</a></li> 631 <li class="tocline1">10.2 <a href="#abuse.of.server.log.information">Abuse of Server Log Information</a></li> 632 <li class="tocline1">10.3 <a href="#attack.pathname">Attacks Based On File and Path Names</a></li> 633 <li class="tocline1">10.4 <a href="#dns.spoofing">DNS Spoofing</a></li> 634 <li class="tocline1">10.5 <a href="#attack.proxies">Proxies and Caching</a></li> 635 <li class="tocline1">10.6 <a href="#attack.DoS">Denial of Service Attacks on Proxies</a></li> 617 <li class="tocline0">4. <a href="#IANA.considerations">IANA Considerations</a><ul class="toc"> 618 <li class="tocline1">4.1 <a href="#message.header.registration">Message Header Registration</a></li> 619 <li class="tocline1">4.2 <a href="#uri.scheme.registration">URI Scheme Registration</a></li> 620 <li class="tocline1">4.3 <a href="#internet.media.type.http">Internet Media Type Registrations</a><ul class="toc"> 621 <li class="tocline1">4.3.1 <a href="#internet.media.type.message.http">Internet Media Type message/http</a></li> 622 <li class="tocline1">4.3.2 <a href="#internet.media.type.application.http">Internet Media Type application/http</a></li> 623 </ul> 624 </li> 625 <li class="tocline1">4.4 <a href="#transfer.coding.registration">Transfer Coding Registry</a></li> 636 626 </ul> 637 627 </li> 638 <li class="tocline0">11. <a href="#ack">Acknowledgments</a></li> 639 <li class="tocline0">12. <a href="#rfc.references">References</a><ul class="toc"> 640 <li class="tocline1">12.1 <a href="#rfc.references.1">Normative References</a></li> 641 <li class="tocline1">12.2 <a href="#rfc.references.2">Informative References</a></li> 628 <li class="tocline0">5. <a href="#security.considerations">Security Considerations</a><ul class="toc"> 629 <li class="tocline1">5.1 <a href="#personal.information">Personal Information</a></li> 630 <li class="tocline1">5.2 <a href="#abuse.of.server.log.information">Abuse of Server Log Information</a></li> 631 <li class="tocline1">5.3 <a href="#attack.pathname">Attacks Based On File and Path Names</a></li> 632 <li class="tocline1">5.4 <a href="#dns.spoofing">DNS Spoofing</a></li> 633 <li class="tocline1">5.5 <a href="#attack.proxies">Proxies and Caching</a></li> 634 <li class="tocline1">5.6 <a href="#attack.DoS">Denial of Service Attacks on Proxies</a></li> 635 </ul> 636 </li> 637 <li class="tocline0">6. <a href="#ack">Acknowledgments</a></li> 638 <li class="tocline0">7. <a href="#rfc.references">References</a><ul class="toc"> 639 <li class="tocline1">7.1 <a href="#rfc.references.1">Normative References</a></li> 640 <li class="tocline1">7.2 <a href="#rfc.references.2">Informative References</a></li> 642 641 </ul> 643 642 </li> … … 769 768 ; "bad" whitespace 770 769 <a href="#rule.whitespace" class="smpl">obs-fold</a> = <a href="#core.rules" class="smpl">CRLF</a> 771 ; see <a href="#header.fields" title="Header Fields">Section 3.2</a>770 ; see <a href="#header.fields" title="Header Fields">Section 2.7.2</a> 772 771 </pre><div id="rule.token.separators"> 773 <p id="rfc.section.1.2.2.p.8"> Many HTTP/1.1 header field values consist of words separated by whitespace or special characters. These special characters <em class="bcp14">MUST</em> be in a quoted string to be used within a parameter value (as defined in <a href="#transfer.codings" title="Transfer Codings">Section 6.2</a>).772 <p id="rfc.section.1.2.2.p.8"> Many HTTP/1.1 header field values consist of words separated by whitespace or special characters. These special characters <em class="bcp14">MUST</em> be in a quoted string to be used within a parameter value (as defined in <a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a>). 774 773 </p> 775 774 </div> … … 832 831 <div id="rfc.iref.r.1"></div> 833 832 <div id="rfc.iref.r.2"></div> 834 <p id="rfc.section.2.1.p.5">A client sends an HTTP request to the server in the form of a request message (<a href="#request" title="Request">Section 4</a>), beginning with a method, URI, and protocol version, followed by MIME-like header fields containing request modifiers, client835 information, and payload metadata, an empty line, and finally the payload body (if any). The server response (<a href="#response" title="Response">Section 5</a>) begins with a status line, including the protocol version, a success or error code, and textual reason phrase, followed833 <p id="rfc.section.2.1.p.5">A client sends an HTTP request to the server in the form of a request message (<a href="#request" title="Request">Section 2.8</a>), beginning with a method, URI, and protocol version, followed by MIME-like header fields containing request modifiers, client 834 information, and payload metadata, an empty line, and finally the payload body (if any). The server response (<a href="#response" title="Response">Section 2.9</a>) begins with a status line, including the protocol version, a success or error code, and textual reason phrase, followed 836 835 by MIME-like header fields containing server information, resource metadata, payload metadata, an empty line, and finally 837 836 the payload body (if any). … … 928 927 </p> 929 928 <p id="rfc.section.2.4.p.3">In HTTP/1.0, most implementations used a new connection for each request/response exchange. In HTTP/1.1, a connection may 930 be used for one or more request/response exchanges, although connections may be closed for a variety of reasons (see <a href="#persistent.connections" title="Persistent Connections">Section 7.1</a>).929 be used for one or more request/response exchanges, although connections may be closed for a variety of reasons (see <a href="#persistent.connections" title="Persistent Connections">Section 2.11.1</a>). 931 930 </p> 932 931 <h2 id="rfc.section.2.5"><a href="#rfc.section.2.5">2.5</a> <a id="http.version" href="#http.version">HTTP Version</a></h2> … … 1007 1006 </p> 1008 1007 <p id="rfc.section.2.6.1.p.5">When an "http" URI is used within a context that calls for access to the indicated resource, a client <em class="bcp14">MAY</em> attempt access by resolving the host to an IP address, establishing a TCP connection to that address on the indicated port, 1009 and sending an HTTP request message to the server containing the URI's identifying data as described in <a href="#request" title="Request">Section 4</a>. If the server responds to that request with a non-interim HTTP response message, as described in <a href="#response" title="Response">Section 5</a>, then that response is considered an authoritative answer to the client's request.1008 and sending an HTTP request message to the server containing the URI's identifying data as described in <a href="#request" title="Request">Section 2.8</a>. If the server responds to that request with a non-interim HTTP response message, as described in <a href="#response" title="Response">Section 2.9</a>, then that response is considered an authoritative answer to the client's request. 1010 1009 </p> 1011 1010 <p id="rfc.section.2.6.1.p.6">Although HTTP is independent of the transport protocol, the "http" scheme is specific to TCP-based services because the name … … 1045 1044 http://EXAMPLE.com:/%7esmith/home.html 1046 1045 </pre><p id="rfc.section.2.6.3.p.5"> <span class="comment" id="rfc.comment.1">[<a href="#rfc.comment.1" class="smpl">rfc.comment.1</a>: [[This paragraph does not belong here. --Roy]]]</span> If path-abempty is the empty string (i.e., there is no slash "/" path separator following the authority), then the "http" 1047 URI <em class="bcp14">MUST</em> be given as "/" when used as a request-target (<a href="#request-target" title="request-target">Section 4.1.2</a>). If a proxy receives a host name which is not a fully qualified domain name, it <em class="bcp14">MAY</em> add its domain to the host name it received. If a proxy receives a fully qualified domain name, the proxy <em class="bcp14">MUST NOT</em> change the host name. 1048 </p> 1049 <h3 id="rfc.section.2.6.4"><a href="#rfc.section.2.6.4">2.6.4</a> <a id="scheme.aliases" href="#scheme.aliases">Scheme aliases considered harmful</a></h3> 1050 <p id="rfc.section.2.6.4.p.1"> <span class="comment" id="rfc.comment.2">[<a href="#rfc.comment.2" class="smpl">rfc.comment.2</a>: TBS: describe why aliases like webcal are harmful.]</span> 1051 </p> 1052 <h2 id="rfc.section.2.7"><a href="#rfc.section.2.7">2.7</a> <a id="http.proxy" href="#http.proxy">Use of HTTP for proxy communication</a></h2> 1053 <p id="rfc.section.2.7.p.1"> <span class="comment" id="rfc.comment.3">[<a href="#rfc.comment.3" class="smpl">rfc.comment.3</a>: TBD: Configured to use HTTP to proxy HTTP or other protocols.]</span> 1054 </p> 1055 <h2 id="rfc.section.2.8"><a href="#rfc.section.2.8">2.8</a> <a id="http.intercept" href="#http.intercept">Interception of HTTP for access control</a></h2> 1056 <p id="rfc.section.2.8.p.1"> <span class="comment" id="rfc.comment.4">[<a href="#rfc.comment.4" class="smpl">rfc.comment.4</a>: TBD: Interception of HTTP traffic for initiating access control.]</span> 1057 </p> 1058 <h2 id="rfc.section.2.9"><a href="#rfc.section.2.9">2.9</a> <a id="http.others" href="#http.others">Use of HTTP by other protocols</a></h2> 1059 <p id="rfc.section.2.9.p.1"> <span class="comment" id="rfc.comment.5">[<a href="#rfc.comment.5" class="smpl">rfc.comment.5</a>: TBD: Profiles of HTTP defined by other protocol. Extensions of HTTP like WebDAV.]</span> 1060 </p> 1061 <h2 id="rfc.section.2.10"><a href="#rfc.section.2.10">2.10</a> <a id="http.media" href="#http.media">Use of HTTP by media type specification</a></h2> 1062 <p id="rfc.section.2.10.p.1"> <span class="comment" id="rfc.comment.6">[<a href="#rfc.comment.6" class="smpl">rfc.comment.6</a>: TBD: Instructions on composing HTTP requests via hypertext formats.]</span> 1063 </p> 1064 <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a> <a id="http.message" href="#http.message">HTTP Message</a></h1> 1046 URI <em class="bcp14">MUST</em> be given as "/" when used as a request-target (<a href="#request-target" title="request-target">Section 2.8.1.2</a>). If a proxy receives a host name which is not a fully qualified domain name, it <em class="bcp14">MAY</em> add its domain to the host name it received. If a proxy receives a fully qualified domain name, the proxy <em class="bcp14">MUST NOT</em> change the host name. 1047 </p> 1048 <h2 id="rfc.section.2.7"><a href="#rfc.section.2.7">2.7</a> <a id="http.message" href="#http.message">HTTP Message</a></h2> 1065 1049 <div id="rfc.iref.h.3"></div> 1066 1050 <div id="rfc.iref.h.4"></div> 1067 1051 <div id="rfc.iref.h.5"></div> 1068 <p id="rfc.section. 3.p.1">All HTTP/1.1 messages consist of a start-line followed by a sequence of characters in a format similar to the Internet Message1052 <p id="rfc.section.2.7.p.1">All HTTP/1.1 messages consist of a start-line followed by a sequence of characters in a format similar to the Internet Message 1069 1053 Format <a href="#RFC5322" id="rfc.xref.RFC5322.2"><cite title="Internet Message Format">[RFC5322]</cite></a>: zero or more header fields (collectively referred to as the "headers" or the "header section"), an empty line indicating 1070 1054 the end of the header section, and an optional message-body. 1071 1055 </p> 1072 <p id="rfc.section. 3.p.2">An HTTP message can either be a request from client to server or a response from server to client. Syntactically, the two1056 <p id="rfc.section.2.7.p.2">An HTTP message can either be a request from client to server or a response from server to client. Syntactically, the two 1073 1057 types of message differ only in the start-line, which is either a Request-Line (for requests) or a Status-Line (for responses), 1074 and in the algorithm for determining the length of the message-body (<a href="#message.length" title="Message Length">Section 3.4</a>). In theory, a client could receive requests and a server could receive responses, distinguishing them by their different1058 and in the algorithm for determining the length of the message-body (<a href="#message.length" title="Message Length">Section 2.7.4</a>). In theory, a client could receive requests and a server could receive responses, distinguishing them by their different 1075 1059 start-line formats, but in practice servers are implemented to only expect a request (a response is interpreted as an unknown 1076 1060 or invalid request method) and clients are implemented to only expect a response. … … 1081 1065 [ <a href="#message.body" class="smpl">message-body</a> ] 1082 1066 <a href="#http.message" class="smpl">start-line</a> = <a href="#request-line" class="smpl">Request-Line</a> / <a href="#status-line" class="smpl">Status-Line</a> 1083 </pre><p id="rfc.section. 3.p.4">Whitespace (WSP) <em class="bcp14">MUST NOT</em> be sent between the start-line and the first header field. The presence of whitespace might be an attempt to trick a noncompliant1067 </pre><p id="rfc.section.2.7.p.4">Whitespace (WSP) <em class="bcp14">MUST NOT</em> be sent between the start-line and the first header field. The presence of whitespace might be an attempt to trick a noncompliant 1084 1068 implementation of HTTP into ignoring that field or processing the next line as a new request, either of which may result in 1085 1069 security issues when implementations within the request chain interpret the same message differently. HTTP/1.1 servers <em class="bcp14">MUST</em> reject such a message with a 400 (Bad Request) response. 1086 1070 </p> 1087 <h 2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a> <a id="message.robustness" href="#message.robustness">Message Parsing Robustness</a></h2>1088 <p id="rfc.section. 3.1.p.1">In the interest of robustness, servers <em class="bcp14">SHOULD</em> ignore at least one empty line received where a Request-Line is expected. In other words, if the server is reading the protocol1071 <h3 id="rfc.section.2.7.1"><a href="#rfc.section.2.7.1">2.7.1</a> <a id="message.robustness" href="#message.robustness">Message Parsing Robustness</a></h3> 1072 <p id="rfc.section.2.7.1.p.1">In the interest of robustness, servers <em class="bcp14">SHOULD</em> ignore at least one empty line received where a Request-Line is expected. In other words, if the server is reading the protocol 1089 1073 stream at the beginning of a message and receives a CRLF first, it should ignore the CRLF. 1090 1074 </p> 1091 <p id="rfc.section. 3.1.p.2">Some old HTTP/1.0 client implementations generate an extra CRLF after a POST request as a lame workaround for some early server1075 <p id="rfc.section.2.7.1.p.2">Some old HTTP/1.0 client implementations generate an extra CRLF after a POST request as a lame workaround for some early server 1092 1076 applications that failed to read message-body content that was not terminated by a line-ending. An HTTP/1.1 client <em class="bcp14">MUST NOT</em> preface or follow a request with an extra CRLF. If terminating the request message-body with a line-ending is desired, then 1093 1077 the client <em class="bcp14">MUST</em> include the terminating CRLF octets as part of the message-body length. 1094 1078 </p> 1095 <p id="rfc.section. 3.1.p.3">The normal procedure for parsing an HTTP message is to read the start-line into a structure, read each header field into a1079 <p id="rfc.section.2.7.1.p.3">The normal procedure for parsing an HTTP message is to read the start-line into a structure, read each header field into a 1096 1080 hash table by field name until the empty line, and then use the parsed data to determine if a message-body is expected. If 1097 1081 a message-body has been indicated, then it is read as a stream until an amount of OCTETs equal to the message-length is read … … 1100 1084 security flaws due to the differing ways that such parsers interpret invalid characters. 1101 1085 </p> 1102 <h 2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a> <a id="header.fields" href="#header.fields">Header Fields</a></h2>1103 <p id="rfc.section. 3.2.p.1">Each HTTP header field consists of a case-insensitive field name followed by a colon (":"), optional whitespace, and the field1086 <h3 id="rfc.section.2.7.2"><a href="#rfc.section.2.7.2">2.7.2</a> <a id="header.fields" href="#header.fields">Header Fields</a></h3> 1087 <p id="rfc.section.2.7.2.p.1">Each HTTP header field consists of a case-insensitive field name followed by a colon (":"), optional whitespace, and the field 1104 1088 value. 1105 1089 </p> … … 1108 1092 <a href="#header.fields" class="smpl">field-value</a> = *( <a href="#header.fields" class="smpl">field-content</a> / <a href="#rule.whitespace" class="smpl">OWS</a> ) 1109 1093 <a href="#header.fields" class="smpl">field-content</a> = *( <a href="#core.rules" class="smpl">WSP</a> / <a href="#core.rules" class="smpl">VCHAR</a> / <a href="#rule.quoted-string" class="smpl">obs-text</a> ) 1110 </pre><p id="rfc.section. 3.2.p.3">No whitespace is allowed between the header field name and colon. For security reasons, any request message received containing1094 </pre><p id="rfc.section.2.7.2.p.3">No whitespace is allowed between the header field name and colon. For security reasons, any request message received containing 1111 1095 such whitespace <em class="bcp14">MUST</em> be rejected with a response code of 400 (Bad Request). A proxy <em class="bcp14">MUST</em> remove any such whitespace from a response message before forwarding the message downstream. 1112 1096 </p> 1113 <p id="rfc.section. 3.2.p.4">A field value <em class="bcp14">MAY</em> be preceded by optional whitespace (OWS); a single SP is preferred. The field value does not include any leading or trailing1097 <p id="rfc.section.2.7.2.p.4">A field value <em class="bcp14">MAY</em> be preceded by optional whitespace (OWS); a single SP is preferred. The field value does not include any leading or trailing 1114 1098 white space: OWS occurring before the first non-whitespace character of the field value or after the last non-whitespace character 1115 1099 of the field value is ignored and <em class="bcp14">SHOULD</em> be removed without changing the meaning of the header field. 1116 1100 </p> 1117 <p id="rfc.section. 3.2.p.5">The order in which header fields with differing field names are received is not significant. However, it is "good practice"1101 <p id="rfc.section.2.7.2.p.5">The order in which header fields with differing field names are received is not significant. However, it is "good practice" 1118 1102 to send header fields that contain control data first, such as Host on requests and Date on responses, so that implementations 1119 1103 can decide when not to handle a message as early as possible. A server <em class="bcp14">MUST</em> wait until the entire header section is received before interpreting a request message, since later header fields might include 1120 1104 conditionals, authentication credentials, or deliberately misleading duplicate header fields that would impact request processing. 1121 1105 </p> 1122 <p id="rfc.section. 3.2.p.6">Multiple header fields with the same field name <em class="bcp14">MAY</em> be sent in a message if and only if the entire field value for that header field is defined as a comma-separated list [i.e.,1123 #(values)]. Multiple header fields with the same field name can be combined into one "field-name: field-value" pair, without1124 changing the semantics of the message, by appending each subsequent field value to the combined field value in order, separated1125 bya comma. The order in which header fields with the same field name are received is therefore significant to the interpretation1106 <p id="rfc.section.2.7.2.p.6">Multiple header fields with the same field name <em class="bcp14">MUST NOT</em> be sent in a message unless the entire field value for that header field is defined as a comma-separated list [i.e., #(values)]. 1107 Multiple header fields with the same field name can be combined into one "field-name: field-value" pair, without changing 1108 the semantics of the message, by appending each subsequent field value to the combined field value in order, separated by 1109 a comma. The order in which header fields with the same field name are received is therefore significant to the interpretation 1126 1110 of the combined field value; a proxy <em class="bcp14">MUST NOT</em> change the order of these field values when forwarding a message. 1127 1111 </p> … … 1131 1115 </p> 1132 1116 </div> 1133 <p id="rfc.section. 3.2.p.8">Historically, HTTP header field values could be extended over multiple lines by preceding each extra line with at least one1117 <p id="rfc.section.2.7.2.p.8">Historically, HTTP header field values could be extended over multiple lines by preceding each extra line with at least one 1134 1118 space or horizontal tab character (line folding). This specification deprecates such line folding except within the message/http 1135 media type (<a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section 9.3.1</a>). HTTP/1.1 senders <em class="bcp14">MUST NOT</em> produce messages that include line folding (i.e., that contain any field-content that matches the obs-fold rule) unless the1119 media type (<a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section 4.3.1</a>). HTTP/1.1 senders <em class="bcp14">MUST NOT</em> produce messages that include line folding (i.e., that contain any field-content that matches the obs-fold rule) unless the 1136 1120 message is intended for packaging within the message/http media type. HTTP/1.1 recipients <em class="bcp14">SHOULD</em> accept line folding and replace any embedded obs-fold whitespace with a single SP prior to interpreting the field value or 1137 1121 forwarding the message downstream. 1138 1122 </p> 1139 <p id="rfc.section. 3.2.p.9">Historically, HTTP has allowed field content with text in the ISO-8859-1 <a href="#ISO-8859-1" id="rfc.xref.ISO-8859-1.1"><cite title="Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1">[ISO-8859-1]</cite></a> character encoding and supported other character sets only through use of <a href="#RFC2047" id="rfc.xref.RFC2047.1"><cite title="MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text">[RFC2047]</cite></a> encoding. In practice, most HTTP header field values use only a subset of the US-ASCII character encoding <a href="#USASCII" id="rfc.xref.USASCII.2"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a>. Newly defined header fields <em class="bcp14">SHOULD</em> limit their field values to US-ASCII characters. Recipients <em class="bcp14">SHOULD</em> treat other (obs-text) octets in field content as opaque data.1123 <p id="rfc.section.2.7.2.p.9">Historically, HTTP has allowed field content with text in the ISO-8859-1 <a href="#ISO-8859-1" id="rfc.xref.ISO-8859-1.1"><cite title="Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1">[ISO-8859-1]</cite></a> character encoding and supported other character sets only through use of <a href="#RFC2047" id="rfc.xref.RFC2047.1"><cite title="MIME (Multipurpose Internet Mail Extensions) Part Three: Message Header Extensions for Non-ASCII Text">[RFC2047]</cite></a> encoding. In practice, most HTTP header field values use only a subset of the US-ASCII character encoding <a href="#USASCII" id="rfc.xref.USASCII.2"><cite title="Coded Character Set -- 7-bit American Standard Code for Information Interchange">[USASCII]</cite></a>. Newly defined header fields <em class="bcp14">SHOULD</em> limit their field values to US-ASCII characters. Recipients <em class="bcp14">SHOULD</em> treat other (obs-text) octets in field content as opaque data. 1140 1124 </p> 1141 1125 <div id="rule.comment"> 1142 <p id="rfc.section. 3.2.p.10"> Comments can be included in some HTTP header fields by surrounding the comment text with parentheses. Comments are only allowed1126 <p id="rfc.section.2.7.2.p.10"> Comments can be included in some HTTP header fields by surrounding the comment text with parentheses. Comments are only allowed 1143 1127 in fields containing "comment" as part of their field value definition. 1144 1128 </p> … … 1147 1131 <a href="#rule.comment" class="smpl">ctext</a> = <a href="#rule.whitespace" class="smpl">OWS</a> / %x21-27 / %x2A-5B / %x5D-7E / <a href="#rule.quoted-string" class="smpl">obs-text</a> 1148 1132 ; <a href="#rule.whitespace" class="smpl">OWS</a> / <<a href="#core.rules" class="smpl">VCHAR</a> except "(", ")", and "\"> / <a href="#rule.quoted-string" class="smpl">obs-text</a> 1149 </pre><h 2 id="rfc.section.3.3"><a href="#rfc.section.3.3">3.3</a> <a id="message.body" href="#message.body">Message Body</a></h2>1150 <p id="rfc.section. 3.3.p.1">The message-body (if any) of an HTTP message is used to carry the entity-body associated with the request or response. The1133 </pre><h3 id="rfc.section.2.7.3"><a href="#rfc.section.2.7.3">2.7.3</a> <a id="message.body" href="#message.body">Message Body</a></h3> 1134 <p id="rfc.section.2.7.3.p.1">The message-body (if any) of an HTTP message is used to carry the entity-body associated with the request or response. The 1151 1135 message-body differs from the entity-body only when a transfer-coding has been applied, as indicated by the Transfer-Encoding 1152 header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.1" title="Transfer-Encoding">Section 8.7</a>).1136 header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.1" title="Transfer-Encoding">Section 3.7</a>). 1153 1137 </p> 1154 1138 <div id="rfc.figure.u.25"></div><pre class="inline"><span id="rfc.iref.g.42"></span> <a href="#message.body" class="smpl">message-body</a> = <a href="#abnf.dependencies" class="smpl">entity-body</a> 1155 1139 / <entity-body encoded as per <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a>> 1156 </pre><p id="rfc.section. 3.3.p.3">Transfer-Encoding <em class="bcp14">MUST</em> be used to indicate any transfer-codings applied by an application to ensure safe and proper transfer of the message. Transfer-Encoding1157 is a property of the message, not of the entity, and thus <em class="bcp14">MAY</em> be added or removed by any application along the request/response chain. (However, <a href="#transfer.codings" title="Transfer Codings">Section 6.2</a> places restrictions on when certain transfer-codings may be used.)1158 </p> 1159 <p id="rfc.section. 3.3.p.4">The rules for when a message-body is allowed in a message differ for requests and responses.</p>1160 <p id="rfc.section. 3.3.p.5">The presence of a message-body in a request is signaled by the inclusion of a Content-Length or Transfer-Encoding header field1140 </pre><p id="rfc.section.2.7.3.p.3">Transfer-Encoding <em class="bcp14">MUST</em> be used to indicate any transfer-codings applied by an application to ensure safe and proper transfer of the message. Transfer-Encoding 1141 is a property of the message, not of the entity, and thus <em class="bcp14">MAY</em> be added or removed by any application along the request/response chain. (However, <a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a> places restrictions on when certain transfer-codings may be used.) 1142 </p> 1143 <p id="rfc.section.2.7.3.p.4">The rules for when a message-body is allowed in a message differ for requests and responses.</p> 1144 <p id="rfc.section.2.7.3.p.5">The presence of a message-body in a request is signaled by the inclusion of a Content-Length or Transfer-Encoding header field 1161 1145 in the request's header fields. When a request message contains both a message-body of non-zero length and a method that does 1162 1146 not define any semantics for that request message-body, then an origin server <em class="bcp14">SHOULD</em> either ignore the message-body or respond with an appropriate error message (e.g., 413). A proxy or gateway, when presented 1163 1147 the same request, <em class="bcp14">SHOULD</em> either forward the request inbound with the message-body or ignore the message-body when determining a response. 1164 1148 </p> 1165 <p id="rfc.section. 3.3.p.6">For response messages, whether or not a message-body is included with a message is dependent on both the request method and1166 the response status code (<a href="#status.code.and.reason.phrase" title="Status Code and Reason Phrase">Section 5.1.1</a>). All responses to the HEAD request method <em class="bcp14">MUST NOT</em> include a message-body, even though the presence of entity-header fields might lead one to believe they do. All 1xx (informational),1149 <p id="rfc.section.2.7.3.p.6">For response messages, whether or not a message-body is included with a message is dependent on both the request method and 1150 the response status code (<a href="#status.code.and.reason.phrase" title="Status Code and Reason Phrase">Section 2.9.1.1</a>). All responses to the HEAD request method <em class="bcp14">MUST NOT</em> include a message-body, even though the presence of entity-header fields might lead one to believe they do. All 1xx (informational), 1167 1151 204 (No Content), and 304 (Not Modified) responses <em class="bcp14">MUST NOT</em> include a message-body. All other responses do include a message-body, although it <em class="bcp14">MAY</em> be of zero length. 1168 1152 </p> 1169 <h 2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a> <a id="message.length" href="#message.length">Message Length</a></h2>1170 <p id="rfc.section. 3.4.p.1">The transfer-length of a message is the length of the message-body as it appears in the message; that is, after any transfer-codings1153 <h3 id="rfc.section.2.7.4"><a href="#rfc.section.2.7.4">2.7.4</a> <a id="message.length" href="#message.length">Message Length</a></h3> 1154 <p id="rfc.section.2.7.4.p.1">The transfer-length of a message is the length of the message-body as it appears in the message; that is, after any transfer-codings 1171 1155 have been applied. When a message-body is included with a message, the transfer-length of that body is determined by one of 1172 1156 the following (in order of precedence): 1173 1157 </p> 1174 <p id="rfc.section. 3.4.p.2"> </p>1158 <p id="rfc.section.2.7.4.p.2"> </p> 1175 1159 <ol> 1176 1160 <li> … … 1180 1164 </li> 1181 1165 <li> 1182 <p>If a Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.2" title="Transfer-Encoding">Section 8.7</a>) is present and the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section 6.2</a>) is used, the transfer-length is defined by the use of this transfer-coding. If a Transfer-Encoding header field is present1166 <p>If a Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.2" title="Transfer-Encoding">Section 3.7</a>) is present and the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a>) is used, the transfer-length is defined by the use of this transfer-coding. If a Transfer-Encoding header field is present 1183 1167 and the "chunked" transfer-coding is not present, the transfer-length is defined by the sender closing the connection. 1184 1168 </p> 1185 1169 </li> 1186 1170 <li> 1187 <p>If a Content-Length header field (<a href="#header.content-length" id="rfc.xref.header.content-length.1" title="Content-Length">Section 8.2</a>) is present, its value in OCTETs represents both the entity-length and the transfer-length. The Content-Length header field <em class="bcp14">MUST NOT</em> be sent if these two lengths are different (i.e., if a Transfer-Encoding header field is present). If a message is received1171 <p>If a Content-Length header field (<a href="#header.content-length" id="rfc.xref.header.content-length.1" title="Content-Length">Section 3.2</a>) is present, its value in OCTETs represents both the entity-length and the transfer-length. The Content-Length header field <em class="bcp14">MUST NOT</em> be sent if these two lengths are different (i.e., if a Transfer-Encoding header field is present). If a message is received 1188 1172 with both a Transfer-Encoding header field and a Content-Length header field, the latter <em class="bcp14">MUST</em> be ignored. 1189 1173 </p> … … 1205 1189 </li> 1206 1190 </ol> 1207 <p id="rfc.section. 3.4.p.3">For compatibility with HTTP/1.0 applications, HTTP/1.1 requests containing a message-body <em class="bcp14">MUST</em> include a valid Content-Length header field unless the server is known to be HTTP/1.1 compliant. If a request contains a message-body1191 <p id="rfc.section.2.7.4.p.3">For compatibility with HTTP/1.0 applications, HTTP/1.1 requests containing a message-body <em class="bcp14">MUST</em> include a valid Content-Length header field unless the server is known to be HTTP/1.1 compliant. If a request contains a message-body 1208 1192 and a Content-Length is not given, the server <em class="bcp14">SHOULD</em> respond with 400 (Bad Request) if it cannot determine the length of the message, or with 411 (Length Required) if it wishes 1209 1193 to insist on receiving a valid Content-Length. 1210 1194 </p> 1211 <p id="rfc.section. 3.4.p.4">All HTTP/1.1 applications that receive entities <em class="bcp14">MUST</em> accept the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section 6.2</a>), thus allowing this mechanism to be used for messages when the message length cannot be determined in advance.1212 </p> 1213 <p id="rfc.section. 3.4.p.5">Messages <em class="bcp14">MUST NOT</em> include both a Content-Length header field and a transfer-coding. If the message does include a transfer-coding, the Content-Length <em class="bcp14">MUST</em> be ignored.1214 </p> 1215 <p id="rfc.section. 3.4.p.6">When a Content-Length is given in a message where a message-body is allowed, its field value <em class="bcp14">MUST</em> exactly match the number of OCTETs in the message-body. HTTP/1.1 user agents <em class="bcp14">MUST</em> notify the user when an invalid length is received and detected.1216 </p> 1217 <h 2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a> <a id="general.header.fields" href="#general.header.fields">General Header Fields</a></h2>1218 <p id="rfc.section. 3.5.p.1">There are a few header fields which have general applicability for both request and response messages, but which do not apply1195 <p id="rfc.section.2.7.4.p.4">All HTTP/1.1 applications that receive entities <em class="bcp14">MUST</em> accept the "chunked" transfer-coding (<a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a>), thus allowing this mechanism to be used for messages when the message length cannot be determined in advance. 1196 </p> 1197 <p id="rfc.section.2.7.4.p.5">Messages <em class="bcp14">MUST NOT</em> include both a Content-Length header field and a transfer-coding. If the message does include a transfer-coding, the Content-Length <em class="bcp14">MUST</em> be ignored. 1198 </p> 1199 <p id="rfc.section.2.7.4.p.6">When a Content-Length is given in a message where a message-body is allowed, its field value <em class="bcp14">MUST</em> exactly match the number of OCTETs in the message-body. HTTP/1.1 user agents <em class="bcp14">MUST</em> notify the user when an invalid length is received and detected. 1200 </p> 1201 <h3 id="rfc.section.2.7.5"><a href="#rfc.section.2.7.5">2.7.5</a> <a id="general.header.fields" href="#general.header.fields">General Header Fields</a></h3> 1202 <p id="rfc.section.2.7.5.p.1">There are a few header fields which have general applicability for both request and response messages, but which do not apply 1219 1203 to the entity being transferred. These header fields apply only to the message being transmitted. 1220 1204 </p> 1221 1205 <div id="rfc.figure.u.26"></div><pre class="inline"><span id="rfc.iref.g.43"></span> <a href="#general.header.fields" class="smpl">general-header</a> = <a href="#abnf.dependencies" class="smpl">Cache-Control</a> ; <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.cache-control" title="Cache-Control">Section 3.2</a> 1222 / <a href="#header.connection" class="smpl">Connection</a> ; <a href="#header.connection" id="rfc.xref.header.connection.1" title="Connection">Section 8.1</a>1223 / <a href="#header.date" class="smpl">Date</a> ; <a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section 8.3</a>1206 / <a href="#header.connection" class="smpl">Connection</a> ; <a href="#header.connection" id="rfc.xref.header.connection.1" title="Connection">Section 3.1</a> 1207 / <a href="#header.date" class="smpl">Date</a> ; <a href="#header.date" id="rfc.xref.header.date.1" title="Date">Section 3.3</a> 1224 1208 / <a href="#abnf.dependencies" class="smpl">Pragma</a> ; <a href="#Part6" id="rfc.xref.Part6.6"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.pragma" title="Pragma">Section 3.4</a> 1225 / <a href="#header.trailer" class="smpl">Trailer</a> ; <a href="#header.trailer" id="rfc.xref.header.trailer.1" title="Trailer">Section 8.6</a>1226 / <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a> ; <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.3" title="Transfer-Encoding">Section 8.7</a>1227 / <a href="#header.upgrade" class="smpl">Upgrade</a> ; <a href="#header.upgrade" id="rfc.xref.header.upgrade.1" title="Upgrade">Section 8.8</a>1228 / <a href="#header.via" class="smpl">Via</a> ; <a href="#header.via" id="rfc.xref.header.via.1" title="Via">Section 8.9</a>1209 / <a href="#header.trailer" class="smpl">Trailer</a> ; <a href="#header.trailer" id="rfc.xref.header.trailer.1" title="Trailer">Section 3.6</a> 1210 / <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding</a> ; <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.3" title="Transfer-Encoding">Section 3.7</a> 1211 / <a href="#header.upgrade" class="smpl">Upgrade</a> ; <a href="#header.upgrade" id="rfc.xref.header.upgrade.1" title="Upgrade">Section 3.8</a> 1212 / <a href="#header.via" class="smpl">Via</a> ; <a href="#header.via" id="rfc.xref.header.via.1" title="Via">Section 3.9</a> 1229 1213 / <a href="#abnf.dependencies" class="smpl">Warning</a> ; <a href="#Part6" id="rfc.xref.Part6.7"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.warning" title="Warning">Section 3.6</a> 1230 </pre><p id="rfc.section. 3.5.p.3">General-header field names can be extended reliably only in combination with a change in the protocol version. However, new1214 </pre><p id="rfc.section.2.7.5.p.3">General-header field names can be extended reliably only in combination with a change in the protocol version. However, new 1231 1215 or experimental header fields may be given the semantics of general header fields if all parties in the communication recognize 1232 1216 them to be general-header fields. Unrecognized header fields are treated as entity-header fields. 1233 1217 </p> 1234 <h 1 id="rfc.section.4"><a href="#rfc.section.4">4.</a> <a id="request" href="#request">Request</a></h1>1235 <p id="rfc.section. 4.p.1">A request message from a client to a server includes, within the first line of that message, the method to be applied to the1218 <h2 id="rfc.section.2.8"><a href="#rfc.section.2.8">2.8</a> <a id="request" href="#request">Request</a></h2> 1219 <p id="rfc.section.2.8.p.1">A request message from a client to a server includes, within the first line of that message, the method to be applied to the 1236 1220 resource, the identifier of the resource, and the protocol version in use. 1237 1221 </p> 1238 <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.44"></span> <a href="#request" class="smpl">Request</a> = <a href="#request-line" class="smpl">Request-Line</a> ; <a href="#request-line" title="Request-Line">Section 4.1</a>1239 *(( <a href="#general.header.fields" class="smpl">general-header</a> ; <a href="#general.header.fields" title="General Header Fields">Section 3.5</a>1222 <div id="rfc.figure.u.27"></div><pre class="inline"><span id="rfc.iref.g.44"></span> <a href="#request" class="smpl">Request</a> = <a href="#request-line" class="smpl">Request-Line</a> ; <a href="#request-line" title="Request-Line">Section 2.8.1</a> 1223 *(( <a href="#general.header.fields" class="smpl">general-header</a> ; <a href="#general.header.fields" title="General Header Fields">Section 2.7.5</a> 1240 1224 / <a href="#abnf.dependencies" class="smpl">request-header</a> ; <a href="#Part2" id="rfc.xref.Part2.3"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#request.header.fields" title="Request Header Fields">Section 3</a> 1241 1225 / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#core.rules" class="smpl">CRLF</a> ) ; <a href="#Part3" id="rfc.xref.Part3.5"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 3.1</a> 1242 1226 <a href="#core.rules" class="smpl">CRLF</a> 1243 [ <a href="#message.body" class="smpl">message-body</a> ] ; <a href="#message.body" title="Message Body">Section 3.3</a>1244 </pre><h 2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a> <a id="request-line" href="#request-line">Request-Line</a></h2>1245 <p id="rfc.section. 4.1.p.1">The Request-Line begins with a method token, followed by the request-target and the protocol version, and ending with CRLF.1227 [ <a href="#message.body" class="smpl">message-body</a> ] ; <a href="#message.body" title="Message Body">Section 2.7.3</a> 1228 </pre><h3 id="rfc.section.2.8.1"><a href="#rfc.section.2.8.1">2.8.1</a> <a id="request-line" href="#request-line">Request-Line</a></h3> 1229 <p id="rfc.section.2.8.1.p.1">The Request-Line begins with a method token, followed by the request-target and the protocol version, and ending with CRLF. 1246 1230 The elements are separated by SP characters. No CR or LF is allowed except in the final CRLF sequence. 1247 1231 </p> 1248 1232 <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.45"></span> <a href="#request-line" class="smpl">Request-Line</a> = <a href="#method" class="smpl">Method</a> <a href="#core.rules" class="smpl">SP</a> <a href="#request-target" class="smpl">request-target</a> <a href="#core.rules" class="smpl">SP</a> <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#core.rules" class="smpl">CRLF</a> 1249 </pre><h 3 id="rfc.section.4.1.1"><a href="#rfc.section.4.1.1">4.1.1</a> <a id="method" href="#method">Method</a></h3>1250 <p id="rfc.section. 4.1.1.p.1">The Method token indicates the method to be performed on the resource identified by the request-target. The method is case-sensitive.</p>1233 </pre><h4 id="rfc.section.2.8.1.1"><a href="#rfc.section.2.8.1.1">2.8.1.1</a> <a id="method" href="#method">Method</a></h4> 1234 <p id="rfc.section.2.8.1.1.p.1">The Method token indicates the method to be performed on the resource identified by the request-target. The method is case-sensitive.</p> 1251 1235 <div id="rfc.figure.u.29"></div><pre class="inline"><span id="rfc.iref.g.46"></span><span id="rfc.iref.g.47"></span> <a href="#method" class="smpl">Method</a> = <a href="#rule.token.separators" class="smpl">token</a> 1252 </pre><h 3 id="rfc.section.4.1.2"><a href="#rfc.section.4.1.2">4.1.2</a> <a id="request-target" href="#request-target">request-target</a></h3>1253 <p id="rfc.section. 4.1.2.p.1">The request-target identifies the resource upon which to apply the request.</p>1236 </pre><h4 id="rfc.section.2.8.1.2"><a href="#rfc.section.2.8.1.2">2.8.1.2</a> <a id="request-target" href="#request-target">request-target</a></h4> 1237 <p id="rfc.section.2.8.1.2.p.1">The request-target identifies the resource upon which to apply the request.</p> 1254 1238 <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.48"></span> <a href="#request-target" class="smpl">request-target</a> = "*" 1255 1239 / <a href="#uri" class="smpl">absolute-URI</a> 1256 1240 / ( <a href="#uri" class="smpl">path-absolute</a> [ "?" <a href="#uri" class="smpl">query</a> ] ) 1257 1241 / <a href="#uri" class="smpl">authority</a> 1258 </pre><p id="rfc.section. 4.1.2.p.3">The four options for request-target are dependent on the nature of the request. The asterisk "*" means that the request does1242 </pre><p id="rfc.section.2.8.1.2.p.3">The four options for request-target are dependent on the nature of the request. The asterisk "*" means that the request does 1259 1243 not apply to a particular resource, but to the server itself, and is only allowed when the method used does not necessarily 1260 1244 apply to a resource. One example would be 1261 1245 </p> 1262 1246 <div id="rfc.figure.u.31"></div><pre class="text"> OPTIONS * HTTP/1.1 1263 </pre><p id="rfc.section. 4.1.2.p.5">The absolute-URI form is <em class="bcp14">REQUIRED</em> when the request is being made to a proxy. The proxy is requested to forward the request or service it from a valid cache,1247 </pre><p id="rfc.section.2.8.1.2.p.5">The absolute-URI form is <em class="bcp14">REQUIRED</em> when the request is being made to a proxy. The proxy is requested to forward the request or service it from a valid cache, 1264 1248 and return the response. Note that the proxy <em class="bcp14">MAY</em> forward the request on to another proxy or directly to the server specified by the absolute-URI. In order to avoid request 1265 1249 loops, a proxy <em class="bcp14">MUST</em> be able to recognize all of its server names, including any aliases, local variations, and the numeric IP address. An example … … 1267 1251 </p> 1268 1252 <div id="rfc.figure.u.32"></div><pre class="text"> GET http://www.example.org/pub/WWW/TheProject.html HTTP/1.1 1269 </pre><p id="rfc.section. 4.1.2.p.7">To allow for transition to absolute-URIs in all requests in future versions of HTTP, all HTTP/1.1 servers <em class="bcp14">MUST</em> accept the absolute-URI form in requests, even though HTTP/1.1 clients will only generate them in requests to proxies.1270 </p> 1271 <p id="rfc.section. 4.1.2.p.8">The authority form is only used by the CONNECT method (<a href="p2-semantics.html#CONNECT" title="CONNECT">Section 7.9</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>).1272 </p> 1273 <p id="rfc.section. 4.1.2.p.9">The most common form of request-target is that used to identify a resource on an origin server or gateway. In this case the1253 </pre><p id="rfc.section.2.8.1.2.p.7">To allow for transition to absolute-URIs in all requests in future versions of HTTP, all HTTP/1.1 servers <em class="bcp14">MUST</em> accept the absolute-URI form in requests, even though HTTP/1.1 clients will only generate them in requests to proxies. 1254 </p> 1255 <p id="rfc.section.2.8.1.2.p.8">The authority form is only used by the CONNECT method (<a href="p2-semantics.html#CONNECT" title="CONNECT">Section 7.9</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). 1256 </p> 1257 <p id="rfc.section.2.8.1.2.p.9">The most common form of request-target is that used to identify a resource on an origin server or gateway. In this case the 1274 1258 absolute path of the URI <em class="bcp14">MUST</em> be transmitted (see <a href="#http.uri" title="http URI scheme">Section 2.6.1</a>, path-absolute) as the request-target, and the network location of the URI (authority) <em class="bcp14">MUST</em> be transmitted in a Host header field. For example, a client wishing to retrieve the resource above directly from the origin 1275 1259 server would create a TCP connection to port 80 of the host "www.example.org" and send the lines: … … 1277 1261 <div id="rfc.figure.u.33"></div><pre class="text"> GET /pub/WWW/TheProject.html HTTP/1.1 1278 1262 Host: www.example.org 1279 </pre><p id="rfc.section. 4.1.2.p.11">followed by the remainder of the Request. Note that the absolute path cannot be empty; if none is present in the original1263 </pre><p id="rfc.section.2.8.1.2.p.11">followed by the remainder of the Request. Note that the absolute path cannot be empty; if none is present in the original 1280 1264 URI, it <em class="bcp14">MUST</em> be given as "/" (the server root). 1281 1265 </p> 1282 <p id="rfc.section. 4.1.2.p.12">If a proxy receives a request without any path in the request-target and the method specified is capable of supporting the1266 <p id="rfc.section.2.8.1.2.p.12">If a proxy receives a request without any path in the request-target and the method specified is capable of supporting the 1283 1267 asterisk form of request-target, then the last proxy on the request chain <em class="bcp14">MUST</em> forward the request with "*" as the final request-target. 1284 1268 </p> … … 1289 1273 Host: www.example.org:8001 1290 1274 </pre> <p>after connecting to port 8001 of host "www.example.org".</p> 1291 <p id="rfc.section. 4.1.2.p.15">The request-target is transmitted in the format specified in <a href="#http.uri" title="http URI scheme">Section 2.6.1</a>. If the request-target is percent-encoded (<a href="#RFC3986" id="rfc.xref.RFC3986.18"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.1">Section 2.1</a>), the origin server <em class="bcp14">MUST</em> decode the request-target in order to properly interpret the request. Servers <em class="bcp14">SHOULD</em> respond to invalid request-targets with an appropriate status code.1292 </p> 1293 <p id="rfc.section. 4.1.2.p.16">A transparent proxy <em class="bcp14">MUST NOT</em> rewrite the "path-absolute" part of the received request-target when forwarding it to the next inbound server, except as noted1275 <p id="rfc.section.2.8.1.2.p.15">The request-target is transmitted in the format specified in <a href="#http.uri" title="http URI scheme">Section 2.6.1</a>. If the request-target is percent-encoded (<a href="#RFC3986" id="rfc.xref.RFC3986.18"><cite title="Uniform Resource Identifier (URI): Generic Syntax">[RFC3986]</cite></a>, <a href="http://tools.ietf.org/html/rfc3986#section-2.1">Section 2.1</a>), the origin server <em class="bcp14">MUST</em> decode the request-target in order to properly interpret the request. Servers <em class="bcp14">SHOULD</em> respond to invalid request-targets with an appropriate status code. 1276 </p> 1277 <p id="rfc.section.2.8.1.2.p.16">A transparent proxy <em class="bcp14">MUST NOT</em> rewrite the "path-absolute" part of the received request-target when forwarding it to the next inbound server, except as noted 1294 1278 above to replace a null path-absolute with "/". 1295 1279 </p> … … 1300 1284 </p> 1301 1285 </div> 1302 <p id="rfc.section. 4.1.2.p.18">HTTP does not place a pre-defined limit on the length of a request-target. A server <em class="bcp14">MUST</em> be prepared to receive URIs of unbounded length and respond with the 414 (URI Too Long) status if the received request-target1286 <p id="rfc.section.2.8.1.2.p.18">HTTP does not place a pre-defined limit on the length of a request-target. A server <em class="bcp14">MUST</em> be prepared to receive URIs of unbounded length and respond with the 414 (URI Too Long) status if the received request-target 1303 1287 would be longer than the server wishes to handle (see <a href="p2-semantics.html#status.414" title="414 URI Too Long">Section 8.4.15</a> of <a href="#Part2" id="rfc.xref.Part2.5"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). 1304 1288 </p> 1305 <p id="rfc.section. 4.1.2.p.19">Various ad-hoc limitations on request-target length are found in practice. It is <em class="bcp14">RECOMMENDED</em> that all HTTP senders and recipients support request-target lengths of 8000 or more OCTETs.1306 </p> 1307 <h 2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a> <a id="the.resource.identified.by.a.request" href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></h2>1308 <p id="rfc.section. 4.2.p.1">The exact resource identified by an Internet request is determined by examining both the request-target and the Host header1289 <p id="rfc.section.2.8.1.2.p.19">Various ad-hoc limitations on request-target length are found in practice. It is <em class="bcp14">RECOMMENDED</em> that all HTTP senders and recipients support request-target lengths of 8000 or more OCTETs. 1290 </p> 1291 <h3 id="rfc.section.2.8.2"><a href="#rfc.section.2.8.2">2.8.2</a> <a id="the.resource.identified.by.a.request" href="#the.resource.identified.by.a.request">The Resource Identified by a Request</a></h3> 1292 <p id="rfc.section.2.8.2.p.1">The exact resource identified by an Internet request is determined by examining both the request-target and the Host header 1309 1293 field. 1310 1294 </p> 1311 <p id="rfc.section. 4.2.p.2">An origin server that does not allow resources to differ by the requested host <em class="bcp14">MAY</em> ignore the Host header field value when determining the resource identified by an HTTP/1.1 request. (But see <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">Appendix B.1.1</a> for other requirements on Host support in HTTP/1.1.)1312 </p> 1313 <p id="rfc.section. 4.2.p.3">An origin server that does differentiate resources based on the host requested (sometimes referred to as virtual hosts or1295 <p id="rfc.section.2.8.2.p.2">An origin server that does not allow resources to differ by the requested host <em class="bcp14">MAY</em> ignore the Host header field value when determining the resource identified by an HTTP/1.1 request. (But see <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">Appendix B.1.1</a> for other requirements on Host support in HTTP/1.1.) 1296 </p> 1297 <p id="rfc.section.2.8.2.p.3">An origin server that does differentiate resources based on the host requested (sometimes referred to as virtual hosts or 1314 1298 vanity host names) <em class="bcp14">MUST</em> use the following rules for determining the requested resource on an HTTP/1.1 request: 1315 1299 </p> … … 1323 1307 </li> 1324 1308 </ol> 1325 <p id="rfc.section. 4.2.p.4">Recipients of an HTTP/1.0 request that lacks a Host header field <em class="bcp14">MAY</em> attempt to use heuristics (e.g., examination of the URI path for something unique to a particular host) in order to determine1309 <p id="rfc.section.2.8.2.p.4">Recipients of an HTTP/1.0 request that lacks a Host header field <em class="bcp14">MAY</em> attempt to use heuristics (e.g., examination of the URI path for something unique to a particular host) in order to determine 1326 1310 what exact resource is being requested. 1327 1311 </p> 1328 <h 1 id="rfc.section.5"><a href="#rfc.section.5">5.</a> <a id="response" href="#response">Response</a></h1>1329 <p id="rfc.section. 5.p.1">After receiving and interpreting a request message, a server responds with an HTTP response message.</p>1330 <div id="rfc.figure.u.36"></div><pre class="inline"><span id="rfc.iref.g.49"></span> <a href="#response" class="smpl">Response</a> = <a href="#status-line" class="smpl">Status-Line</a> ; <a href="#status-line" title="Status-Line">Section 5.1</a>1331 *(( <a href="#general.header.fields" class="smpl">general-header</a> ; <a href="#general.header.fields" title="General Header Fields">Section 3.5</a>1312 <h2 id="rfc.section.2.9"><a href="#rfc.section.2.9">2.9</a> <a id="response" href="#response">Response</a></h2> 1313 <p id="rfc.section.2.9.p.1">After receiving and interpreting a request message, a server responds with an HTTP response message.</p> 1314 <div id="rfc.figure.u.36"></div><pre class="inline"><span id="rfc.iref.g.49"></span> <a href="#response" class="smpl">Response</a> = <a href="#status-line" class="smpl">Status-Line</a> ; <a href="#status-line" title="Status-Line">Section 2.9.1</a> 1315 *(( <a href="#general.header.fields" class="smpl">general-header</a> ; <a href="#general.header.fields" title="General Header Fields">Section 2.7.5</a> 1332 1316 / <a href="#abnf.dependencies" class="smpl">response-header</a> ; <a href="#Part2" id="rfc.xref.Part2.6"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>, <a href="p2-semantics.html#response.header.fields" title="Response Header Fields">Section 5</a> 1333 1317 / <a href="#abnf.dependencies" class="smpl">entity-header</a> ) <a href="#core.rules" class="smpl">CRLF</a> ) ; <a href="#Part3" id="rfc.xref.Part3.6"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="p3-payload.html#entity.header.fields" title="Entity Header Fields">Section 3.1</a> 1334 1318 <a href="#core.rules" class="smpl">CRLF</a> 1335 [ <a href="#message.body" class="smpl">message-body</a> ] ; <a href="#message.body" title="Message Body">Section 3.3</a>1336 </pre><h 2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a> <a id="status-line" href="#status-line">Status-Line</a></h2>1337 <p id="rfc.section. 5.1.p.1">The first line of a Response message is the Status-Line, consisting of the protocol version followed by a numeric status code1319 [ <a href="#message.body" class="smpl">message-body</a> ] ; <a href="#message.body" title="Message Body">Section 2.7.3</a> 1320 </pre><h3 id="rfc.section.2.9.1"><a href="#rfc.section.2.9.1">2.9.1</a> <a id="status-line" href="#status-line">Status-Line</a></h3> 1321 <p id="rfc.section.2.9.1.p.1">The first line of a Response message is the Status-Line, consisting of the protocol version followed by a numeric status code 1338 1322 and its associated textual phrase, with each element separated by SP characters. No CR or LF is allowed except in the final 1339 1323 CRLF sequence. 1340 1324 </p> 1341 1325 <div id="rfc.figure.u.37"></div><pre class="inline"><span id="rfc.iref.g.50"></span> <a href="#status-line" class="smpl">Status-Line</a> = <a href="#http.version" class="smpl">HTTP-Version</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a> <a href="#core.rules" class="smpl">SP</a> <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a> <a href="#core.rules" class="smpl">CRLF</a> 1342 </pre><h 3 id="rfc.section.5.1.1"><a href="#rfc.section.5.1.1">5.1.1</a> <a id="status.code.and.reason.phrase" href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h3>1343 <p id="rfc.section. 5.1.1.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request. These codes1326 </pre><h4 id="rfc.section.2.9.1.1"><a href="#rfc.section.2.9.1.1">2.9.1.1</a> <a id="status.code.and.reason.phrase" href="#status.code.and.reason.phrase">Status Code and Reason Phrase</a></h4> 1327 <p id="rfc.section.2.9.1.1.p.1">The Status-Code element is a 3-digit integer result code of the attempt to understand and satisfy the request. These codes 1344 1328 are fully defined in <a href="p2-semantics.html#status.codes" title="Status Code Definitions">Section 8</a> of <a href="#Part2" id="rfc.xref.Part2.7"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>. The Reason Phrase exists for the sole purpose of providing a textual description associated with the numeric status code, 1345 1329 out of deference to earlier Internet application protocols that were more frequently used with interactive text clients. A 1346 1330 client <em class="bcp14">SHOULD</em> ignore the content of the Reason Phrase. 1347 1331 </p> 1348 <p id="rfc.section. 5.1.1.p.2">The first digit of the Status-Code defines the class of response. The last two digits do not have any categorization role.1332 <p id="rfc.section.2.9.1.1.p.2">The first digit of the Status-Code defines the class of response. The last two digits do not have any categorization role. 1349 1333 There are 5 values for the first digit: 1350 1334 </p> … … 1358 1342 <div id="rfc.figure.u.38"></div><pre class="inline"><span id="rfc.iref.g.51"></span><span id="rfc.iref.g.52"></span><span id="rfc.iref.g.53"></span> <a href="#status.code.and.reason.phrase" class="smpl">Status-Code</a> = 3<a href="#core.rules" class="smpl">DIGIT</a> 1359 1343 <a href="#status.code.and.reason.phrase" class="smpl">Reason-Phrase</a> = *( <a href="#core.rules" class="smpl">WSP</a> / <a href="#core.rules" class="smpl">VCHAR</a> / <a href="#rule.quoted-string" class="smpl">obs-text</a> ) 1360 </pre><h 1 id="rfc.section.6"><a href="#rfc.section.6">6.</a> <a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h1>1361 <h 2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a> <a id="date.time.formats.full.date" href="#date.time.formats.full.date">Date/Time Formats: Full Date</a></h2>1362 <p id="rfc.section. 6.1.p.1">HTTP applications have historically allowed three different formats for the representation of date/time stamps:</p>1344 </pre><h2 id="rfc.section.2.10"><a href="#rfc.section.2.10">2.10</a> <a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h2> 1345 <h3 id="rfc.section.2.10.1"><a href="#rfc.section.2.10.1">2.10.1</a> <a id="date.time.formats.full.date" href="#date.time.formats.full.date">Date/Time Formats: Full Date</a></h3> 1346 <p id="rfc.section.2.10.1.p.1">HTTP applications have historically allowed three different formats for the representation of date/time stamps:</p> 1363 1347 <div id="rfc.figure.u.39"></div><pre class="text"> Sun, 06 Nov 1994 08:49:37 GMT ; RFC 1123 1364 1348 Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format 1365 1349 Sun Nov 6 08:49:37 1994 ; ANSI C's asctime() format 1366 </pre><p id="rfc.section. 6.1.p.3">The first format is preferred as an Internet standard and represents a fixed-length subset of that defined by <a href="#RFC1123" id="rfc.xref.RFC1123.1"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>. The other formats are described here only for compatibility with obsolete implementations. HTTP/1.1 clients and servers1350 </pre><p id="rfc.section.2.10.1.p.3">The first format is preferred as an Internet standard and represents a fixed-length subset of that defined by <a href="#RFC1123" id="rfc.xref.RFC1123.1"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>. The other formats are described here only for compatibility with obsolete implementations. HTTP/1.1 clients and servers 1367 1351 that parse the date value <em class="bcp14">MUST</em> accept all three formats (for compatibility with HTTP/1.0), though they <em class="bcp14">MUST</em> only generate the RFC 1123 format for representing HTTP-date values in header fields. See <a href="#tolerant.applications" title="Tolerant Applications">Appendix A</a> for further information. 1368 1352 </p> 1369 <p id="rfc.section. 6.1.p.4">All HTTP date/time stamps <em class="bcp14">MUST</em> be represented in Greenwich Mean Time (GMT), without exception. For the purposes of HTTP, GMT is exactly equal to UTC (Coordinated1353 <p id="rfc.section.2.10.1.p.4">All HTTP date/time stamps <em class="bcp14">MUST</em> be represented in Greenwich Mean Time (GMT), without exception. For the purposes of HTTP, GMT is exactly equal to UTC (Coordinated 1370 1354 Universal Time). This is indicated in the first two formats by the inclusion of "GMT" as the three-letter abbreviation for 1371 1355 time zone, and <em class="bcp14">MUST</em> be assumed when reading the asctime format. HTTP-date is case sensitive and <em class="bcp14">MUST NOT</em> include additional whitespace beyond that specifically included as SP in the grammar. … … 1373 1357 <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.54"></span> <a href="#date.time.formats.full.date" class="smpl">HTTP-date</a> = <a href="#preferred.date.format" class="smpl">rfc1123-date</a> / <a href="#obsolete.date.formats" class="smpl">obs-date</a> 1374 1358 </pre><div id="preferred.date.format"> 1375 <p id="rfc.section. 6.1.p.6"> Preferred format:</p>1359 <p id="rfc.section.2.10.1.p.6"> Preferred format:</p> 1376 1360 </div> 1377 1361 <div id="rfc.figure.u.41"></div><pre class="inline"><span id="rfc.iref.g.55"></span><span id="rfc.iref.g.56"></span><span id="rfc.iref.g.57"></span><span id="rfc.iref.g.58"></span><span id="rfc.iref.g.59"></span><span id="rfc.iref.g.60"></span><span id="rfc.iref.g.61"></span><span id="rfc.iref.g.62"></span><span id="rfc.iref.g.63"></span><span id="rfc.iref.g.64"></span><span id="rfc.iref.g.65"></span><span id="rfc.iref.g.66"></span> <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#core.rules" class="smpl">SP</a> date1 <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#core.rules" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a> … … 1411 1395 <a href="#preferred.date.format" class="smpl">minute</a> = 2<a href="#core.rules" class="smpl">DIGIT</a> 1412 1396 <a href="#preferred.date.format" class="smpl">second</a> = 2<a href="#core.rules" class="smpl">DIGIT</a> 1413 </pre><p id="rfc.section. 6.1.p.8">The semantics of <a href="#preferred.date.format" class="smpl">day-name</a>, <a href="#preferred.date.format" class="smpl">day</a>, <a href="#preferred.date.format" class="smpl">month</a>, <a href="#preferred.date.format" class="smpl">year</a>, and <a href="#preferred.date.format" class="smpl">time-of-day</a> are the same as those defined for the RFC 5322 constructs with the corresponding name (<a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.3">Section 3.3</a>).1397 </pre><p id="rfc.section.2.10.1.p.8">The semantics of <a href="#preferred.date.format" class="smpl">day-name</a>, <a href="#preferred.date.format" class="smpl">day</a>, <a href="#preferred.date.format" class="smpl">month</a>, <a href="#preferred.date.format" class="smpl">year</a>, and <a href="#preferred.date.format" class="smpl">time-of-day</a> are the same as those defined for the RFC 5322 constructs with the corresponding name (<a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.3">Section 3.3</a>). 1414 1398 </p> 1415 1399 <div id="obsolete.date.formats"> 1416 <p id="rfc.section. 6.1.p.9"> Obsolete formats:</p>1400 <p id="rfc.section.2.10.1.p.9"> Obsolete formats:</p> 1417 1401 </div> 1418 1402 <div id="rfc.figure.u.42"></div><pre class="inline"><span id="rfc.iref.g.67"></span> <a href="#obsolete.date.formats" class="smpl">obs-date</a> = <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> / <a href="#obsolete.date.formats" class="smpl">asctime-date</a> … … 1441 1425 </p> 1442 1426 </div> 1443 <h 2 id="rfc.section.6.2"><a href="#rfc.section.6.2">6.2</a> <a id="transfer.codings" href="#transfer.codings">Transfer Codings</a></h2>1444 <p id="rfc.section. 6.2.p.1">Transfer-coding values are used to indicate an encoding transformation that has been, can be, or may need to be applied to1427 <h3 id="rfc.section.2.10.2"><a href="#rfc.section.2.10.2">2.10.2</a> <a id="transfer.codings" href="#transfer.codings">Transfer Codings</a></h3> 1428 <p id="rfc.section.2.10.2.p.1">Transfer-coding values are used to indicate an encoding transformation that has been, can be, or may need to be applied to 1445 1429 an entity-body in order to ensure "safe transport" through the network. This differs from a content coding in that the transfer-coding 1446 1430 is a property of the message, not of the original entity. … … 1449 1433 <a href="#transfer.codings" class="smpl">transfer-extension</a> = <a href="#rule.token.separators" class="smpl">token</a> *( <a href="#rule.whitespace" class="smpl">OWS</a> ";" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#rule.parameter" class="smpl">transfer-parameter</a> ) 1450 1434 </pre><div id="rule.parameter"> 1451 <p id="rfc.section. 6.2.p.3"> Parameters are in the form of attribute/value pairs.</p>1435 <p id="rfc.section.2.10.2.p.3"> Parameters are in the form of attribute/value pairs.</p> 1452 1436 </div> 1453 1437 <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.72"></span><span id="rfc.iref.g.73"></span><span id="rfc.iref.g.74"></span><span id="rfc.iref.g.75"></span><span id="rfc.iref.g.76"></span> <a href="#rule.parameter" class="smpl">transfer-parameter</a> = <a href="#rule.parameter" class="smpl">attribute</a> <a href="#rule.whitespace" class="smpl">BWS</a> "=" <a href="#rule.whitespace" class="smpl">BWS</a> <a href="#rule.parameter" class="smpl">value</a> 1454 1438 <a href="#rule.parameter" class="smpl">attribute</a> = <a href="#rule.token.separators" class="smpl">token</a> 1455 1439 <a href="#rule.parameter" class="smpl">value</a> = <a href="#rule.token.separators" class="smpl">token</a> / <a href="#rule.quoted-string" class="smpl">quoted-string</a> 1456 </pre><p id="rfc.section. 6.2.p.5">All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in the TE header field (<a href="#header.te" id="rfc.xref.header.te.1" title="TE">Section 8.5</a>) and in the Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.4" title="Transfer-Encoding">Section 8.7</a>).1457 </p> 1458 <p id="rfc.section. 6.2.p.6">Whenever a transfer-coding is applied to a message-body, the set of transfer-codings <em class="bcp14">MUST</em> include "chunked", unless the message indicates it is terminated by closing the connection. When the "chunked" transfer-coding1440 </pre><p id="rfc.section.2.10.2.p.5">All transfer-coding values are case-insensitive. HTTP/1.1 uses transfer-coding values in the TE header field (<a href="#header.te" id="rfc.xref.header.te.1" title="TE">Section 3.5</a>) and in the Transfer-Encoding header field (<a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.4" title="Transfer-Encoding">Section 3.7</a>). 1441 </p> 1442 <p id="rfc.section.2.10.2.p.6">Whenever a transfer-coding is applied to a message-body, the set of transfer-codings <em class="bcp14">MUST</em> include "chunked", unless the message indicates it is terminated by closing the connection. When the "chunked" transfer-coding 1459 1443 is used, it <em class="bcp14">MUST</em> be the last transfer-coding applied to the message-body. The "chunked" transfer-coding <em class="bcp14">MUST NOT</em> be applied more than once to a message-body. These rules allow the recipient to determine the transfer-length of the message 1460 (<a href="#message.length" title="Message Length">Section 3.4</a>).1461 </p> 1462 <p id="rfc.section. 6.2.p.7">Transfer-codings are analogous to the Content-Transfer-Encoding values of MIME, which were designed to enable safe transport1444 (<a href="#message.length" title="Message Length">Section 2.7.4</a>). 1445 </p> 1446 <p id="rfc.section.2.10.2.p.7">Transfer-codings are analogous to the Content-Transfer-Encoding values of MIME, which were designed to enable safe transport 1463 1447 of binary data over a 7-bit transport service (<a href="#RFC2045" id="rfc.xref.RFC2045.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>, <a href="http://tools.ietf.org/html/rfc2045#section-6">Section 6</a>). However, safe transport has a different focus for an 8bit-clean transfer protocol. In HTTP, the only unsafe characteristic 1464 of message-bodies is the difficulty in determining the exact body length (<a href="#message.length" title="Message Length">Section 3.4</a>), or the desire to encrypt data over a shared transport.1465 </p> 1466 <p id="rfc.section. 6.2.p.8">The Internet Assigned Numbers Authority (IANA) acts as a registry for transfer-coding value tokens. Initially, the registry1467 contains the following tokens: "chunked" (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 6.2.1</a>), "gzip", "compress", and "deflate" (<a href="p3-payload.html#content.codings" title="Content Codings">Section 2.2</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>).1468 </p> 1469 <p id="rfc.section. 6.2.p.9">New transfer-coding value tokens <em class="bcp14">SHOULD</em> be registered in the same way as new content-coding value tokens (<a href="p3-payload.html#content.codings" title="Content Codings">Section 2.2</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>).1470 </p> 1471 <p id="rfc.section. 6.2.p.10">A server which receives an entity-body with a transfer-coding it does not understand <em class="bcp14">SHOULD</em> return 501 (Not Implemented), and close the connection. A server <em class="bcp14">MUST NOT</em> send transfer-codings to an HTTP/1.0 client.1472 </p> 1473 <h 3 id="rfc.section.6.2.1"><a href="#rfc.section.6.2.1">6.2.1</a> <a id="chunked.transfer.encoding" href="#chunked.transfer.encoding">Chunked Transfer Coding</a></h3>1474 <p id="rfc.section. 6.2.1.p.1">The chunked encoding modifies the body of a message in order to transfer it as a series of chunks, each with its own size1448 of message-bodies is the difficulty in determining the exact body length (<a href="#message.length" title="Message Length">Section 2.7.4</a>), or the desire to encrypt data over a shared transport. 1449 </p> 1450 <p id="rfc.section.2.10.2.p.8">The Internet Assigned Numbers Authority (IANA) acts as a registry for transfer-coding value tokens. Initially, the registry 1451 contains the following tokens: "chunked" (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 2.10.2.1</a>), "gzip", "compress", and "deflate" (<a href="p3-payload.html#content.codings" title="Content Codings">Section 2.2</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>). 1452 </p> 1453 <p id="rfc.section.2.10.2.p.9">New transfer-coding value tokens <em class="bcp14">SHOULD</em> be registered in the same way as new content-coding value tokens (<a href="p3-payload.html#content.codings" title="Content Codings">Section 2.2</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>). 1454 </p> 1455 <p id="rfc.section.2.10.2.p.10">A server which receives an entity-body with a transfer-coding it does not understand <em class="bcp14">SHOULD</em> return 501 (Not Implemented), and close the connection. A server <em class="bcp14">MUST NOT</em> send transfer-codings to an HTTP/1.0 client. 1456 </p> 1457 <h4 id="rfc.section.2.10.2.1"><a href="#rfc.section.2.10.2.1">2.10.2.1</a> <a id="chunked.transfer.encoding" href="#chunked.transfer.encoding">Chunked Transfer Coding</a></h4> 1458 <p id="rfc.section.2.10.2.1.p.1">The chunked encoding modifies the body of a message in order to transfer it as a series of chunks, each with its own size 1475 1459 indicator, followed by an <em class="bcp14">OPTIONAL</em> trailer containing entity-header fields. This allows dynamically produced content to be transferred along with the information 1476 1460 necessary for the recipient to verify that it has received the full message. … … 1492 1476 <a href="#chunked.transfer.encoding" class="smpl">chunk-data</a> = 1*<a href="#core.rules" class="smpl">OCTET</a> ; a sequence of chunk-size octets 1493 1477 <a href="#chunked.transfer.encoding" class="smpl">trailer-part</a> = *( <a href="#abnf.dependencies" class="smpl">entity-header</a> <a href="#core.rules" class="smpl">CRLF</a> ) 1494 </pre><p id="rfc.section. 6.2.1.p.3">The chunk-size field is a string of hex digits indicating the size of the chunk-data in octets. The chunked encoding is ended1478 </pre><p id="rfc.section.2.10.2.1.p.3">The chunk-size field is a string of hex digits indicating the size of the chunk-data in octets. The chunked encoding is ended 1495 1479 by any chunk whose size is zero, followed by the trailer, which is terminated by an empty line. 1496 1480 </p> 1497 <p id="rfc.section. 6.2.1.p.4">The trailer allows the sender to include additional HTTP header fields at the end of the message. The Trailer header field1498 can be used to indicate which header fields are included in a trailer (see <a href="#header.trailer" id="rfc.xref.header.trailer.2" title="Trailer">Section 8.6</a>).1499 </p> 1500 <p id="rfc.section. 6.2.1.p.5">A server using chunked transfer-coding in a response <em class="bcp14">MUST NOT</em> use the trailer for any header fields unless at least one of the following is true:1481 <p id="rfc.section.2.10.2.1.p.4">The trailer allows the sender to include additional HTTP header fields at the end of the message. The Trailer header field 1482 can be used to indicate which header fields are included in a trailer (see <a href="#header.trailer" id="rfc.xref.header.trailer.2" title="Trailer">Section 3.6</a>). 1483 </p> 1484 <p id="rfc.section.2.10.2.1.p.5">A server using chunked transfer-coding in a response <em class="bcp14">MUST NOT</em> use the trailer for any header fields unless at least one of the following is true: 1501 1485 </p> 1502 1486 <ol> 1503 1487 <li>the request included a TE header field that indicates "trailers" is acceptable in the transfer-coding of the response, as 1504 described in <a href="#header.te" id="rfc.xref.header.te.2" title="TE">Section 8.5</a>; or,1488 described in <a href="#header.te" id="rfc.xref.header.te.2" title="TE">Section 3.5</a>; or, 1505 1489 </li> 1506 1490 <li>the server is the origin server for the response, the trailer fields consist entirely of optional metadata, and the recipient … … 1509 1493 </li> 1510 1494 </ol> 1511 <p id="rfc.section. 6.2.1.p.6">This requirement prevents an interoperability failure when the message is being received by an HTTP/1.1 (or later) proxy and1495 <p id="rfc.section.2.10.2.1.p.6">This requirement prevents an interoperability failure when the message is being received by an HTTP/1.1 (or later) proxy and 1512 1496 forwarded to an HTTP/1.0 recipient. It avoids a situation where compliance with the protocol would have necessitated a possibly 1513 1497 infinite buffer on the proxy. 1514 1498 </p> 1515 <p id="rfc.section. 6.2.1.p.7">A process for decoding the "chunked" transfer-coding can be represented in pseudo-code as:</p>1499 <p id="rfc.section.2.10.2.1.p.7">A process for decoding the "chunked" transfer-coding can be represented in pseudo-code as:</p> 1516 1500 <div id="rfc.figure.u.48"></div><pre class="text"> length := 0 1517 1501 read chunk-size, chunk-ext (if any) and CRLF … … 1529 1513 Content-Length := length 1530 1514 Remove "chunked" from Transfer-Encoding 1531 </pre><p id="rfc.section. 6.2.1.p.9">All HTTP/1.1 applications <em class="bcp14">MUST</em> be able to receive and decode the "chunked" transfer-coding, and <em class="bcp14">MUST</em> ignore chunk-ext extensions they do not understand.1532 </p> 1533 <h 2 id="rfc.section.6.3"><a href="#rfc.section.6.3">6.3</a> <a id="product.tokens" href="#product.tokens">Product Tokens</a></h2>1534 <p id="rfc.section. 6.3.p.1">Product tokens are used to allow communicating applications to identify themselves by software name and version. Most fields1515 </pre><p id="rfc.section.2.10.2.1.p.9">All HTTP/1.1 applications <em class="bcp14">MUST</em> be able to receive and decode the "chunked" transfer-coding, and <em class="bcp14">MUST</em> ignore chunk-ext extensions they do not understand. 1516 </p> 1517 <h3 id="rfc.section.2.10.3"><a href="#rfc.section.2.10.3">2.10.3</a> <a id="product.tokens" href="#product.tokens">Product Tokens</a></h3> 1518 <p id="rfc.section.2.10.3.p.1">Product tokens are used to allow communicating applications to identify themselves by software name and version. Most fields 1535 1519 using product tokens also allow sub-products which form a significant part of the application to be listed, separated by whitespace. 1536 1520 By convention, the products are listed in order of their significance for identifying the application. … … 1538 1522 <div id="rfc.figure.u.49"></div><pre class="inline"><span id="rfc.iref.g.86"></span><span id="rfc.iref.g.87"></span> <a href="#product.tokens" class="smpl">product</a> = <a href="#rule.token.separators" class="smpl">token</a> ["/" <a href="#product.tokens" class="smpl">product-version</a>] 1539 1523 <a href="#product.tokens" class="smpl">product-version</a> = <a href="#rule.token.separators" class="smpl">token</a> 1540 </pre><p id="rfc.section. 6.3.p.3">Examples:</p>1524 </pre><p id="rfc.section.2.10.3.p.3">Examples:</p> 1541 1525 <div id="rfc.figure.u.50"></div><pre class="text"> User-Agent: CERN-LineMode/2.15 libwww/2.17b3 1542 1526 Server: Apache/0.8.4 1543 </pre><p id="rfc.section. 6.3.p.5">Product tokens <em class="bcp14">SHOULD</em> be short and to the point. They <em class="bcp14">MUST NOT</em> be used for advertising or other non-essential information. Although any token character <em class="bcp14">MAY</em> appear in a product-version, this token <em class="bcp14">SHOULD</em> only be used for a version identifier (i.e., successive versions of the same product <em class="bcp14">SHOULD</em> only differ in the product-version portion of the product value).1544 </p> 1545 <h 2 id="rfc.section.6.4"><a href="#rfc.section.6.4">6.4</a> <a id="quality.values" href="#quality.values">Quality Values</a></h2>1546 <p id="rfc.section. 6.4.p.1">Both transfer codings (TE request header, <a href="#header.te" id="rfc.xref.header.te.3" title="TE">Section 8.5</a>) and content negotiation (<a href="p3-payload.html#content.negotiation" title="Content Negotiation">Section 4</a> of <a href="#Part3" id="rfc.xref.Part3.9"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) use short "floating point" numbers to indicate the relative importance ("weight") of various negotiable parameters. A weight1527 </pre><p id="rfc.section.2.10.3.p.5">Product tokens <em class="bcp14">SHOULD</em> be short and to the point. They <em class="bcp14">MUST NOT</em> be used for advertising or other non-essential information. Although any token character <em class="bcp14">MAY</em> appear in a product-version, this token <em class="bcp14">SHOULD</em> only be used for a version identifier (i.e., successive versions of the same product <em class="bcp14">SHOULD</em> only differ in the product-version portion of the product value). 1528 </p> 1529 <h3 id="rfc.section.2.10.4"><a href="#rfc.section.2.10.4">2.10.4</a> <a id="quality.values" href="#quality.values">Quality Values</a></h3> 1530 <p id="rfc.section.2.10.4.p.1">Both transfer codings (TE request header, <a href="#header.te" id="rfc.xref.header.te.3" title="TE">Section 3.5</a>) and content negotiation (<a href="p3-payload.html#content.negotiation" title="Content Negotiation">Section 4</a> of <a href="#Part3" id="rfc.xref.Part3.9"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>) use short "floating point" numbers to indicate the relative importance ("weight") of various negotiable parameters. A weight 1547 1531 is normalized to a real number in the range 0 through 1, where 0 is the minimum and 1 the maximum value. If a parameter has 1548 1532 a quality value of 0, then content with this parameter is `not acceptable' for the client. HTTP/1.1 applications <em class="bcp14">MUST NOT</em> generate more than three digits after the decimal point. User configuration of these values <em class="bcp14">SHOULD</em> also be limited in this fashion. … … 1554 1538 </p> 1555 1539 </div> 1556 <h 1 id="rfc.section.7"><a href="#rfc.section.7">7.</a> <a id="connections" href="#connections">Connections</a></h1>1557 <h 2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a> <a id="persistent.connections" href="#persistent.connections">Persistent Connections</a></h2>1558 <h 3 id="rfc.section.7.1.1"><a href="#rfc.section.7.1.1">7.1.1</a> <a id="persistent.purpose" href="#persistent.purpose">Purpose</a></h3>1559 <p id="rfc.section. 7.1.1.p.1">Prior to persistent connections, a separate TCP connection was established to fetch each URL, increasing the load on HTTP1540 <h2 id="rfc.section.2.11"><a href="#rfc.section.2.11">2.11</a> <a id="connections" href="#connections">Connections</a></h2> 1541 <h3 id="rfc.section.2.11.1"><a href="#rfc.section.2.11.1">2.11.1</a> <a id="persistent.connections" href="#persistent.connections">Persistent Connections</a></h3> 1542 <h4 id="rfc.section.2.11.1.1"><a href="#rfc.section.2.11.1.1">2.11.1.1</a> <a id="persistent.purpose" href="#persistent.purpose">Purpose</a></h4> 1543 <p id="rfc.section.2.11.1.1.p.1">Prior to persistent connections, a separate TCP connection was established to fetch each URL, increasing the load on HTTP 1560 1544 servers and causing congestion on the Internet. The use of inline images and other associated data often require a client 1561 1545 to make multiple requests of the same server in a short amount of time. Analysis of these performance problems and results 1562 1546 from a prototype implementation are available <a href="#Pad1995" id="rfc.xref.Pad1995.1"><cite title="Improving HTTP Latency">[Pad1995]</cite></a> <a href="#Spe" id="rfc.xref.Spe.1"><cite title="Analysis of HTTP Performance Problems">[Spe]</cite></a>. Implementation experience and measurements of actual HTTP/1.1 implementations show good results <a href="#Nie1997" id="rfc.xref.Nie1997.1"><cite title="Network Performance Effects of HTTP/1.1, CSS1, and PNG">[Nie1997]</cite></a>. Alternatives have also been explored, for example, T/TCP <a href="#Tou1998" id="rfc.xref.Tou1998.1"><cite title="Analysis of HTTP Performance">[Tou1998]</cite></a>. 1563 1547 </p> 1564 <p id="rfc.section. 7.1.1.p.2">Persistent HTTP connections have a number of advantages: </p>1548 <p id="rfc.section.2.11.1.1.p.2">Persistent HTTP connections have a number of advantages: </p> 1565 1549 <ul> 1566 1550 <li>By opening and closing fewer TCP connections, CPU time is saved in routers and hosts (clients, servers, proxies, gateways, … … 1579 1563 </li> 1580 1564 </ul> 1581 <p id="rfc.section. 7.1.1.p.3">HTTP implementations <em class="bcp14">SHOULD</em> implement persistent connections.1582 </p> 1583 <h 3 id="rfc.section.7.1.2"><a href="#rfc.section.7.1.2">7.1.2</a> <a id="persistent.overall" href="#persistent.overall">Overall Operation</a></h3>1584 <p id="rfc.section. 7.1.2.p.1">A significant difference between HTTP/1.1 and earlier versions of HTTP is that persistent connections are the default behavior1565 <p id="rfc.section.2.11.1.1.p.3">HTTP implementations <em class="bcp14">SHOULD</em> implement persistent connections. 1566 </p> 1567 <h4 id="rfc.section.2.11.1.2"><a href="#rfc.section.2.11.1.2">2.11.1.2</a> <a id="persistent.overall" href="#persistent.overall">Overall Operation</a></h4> 1568 <p id="rfc.section.2.11.1.2.p.1">A significant difference between HTTP/1.1 and earlier versions of HTTP is that persistent connections are the default behavior 1585 1569 of any HTTP connection. That is, unless otherwise indicated, the client <em class="bcp14">SHOULD</em> assume that the server will maintain a persistent connection, even after error responses from the server. 1586 1570 </p> 1587 <p id="rfc.section. 7.1.2.p.2">Persistent connections provide a mechanism by which a client and a server can signal the close of a TCP connection. This signaling1588 takes place using the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.2" title="Connection">Section 8.1</a>). Once a close has been signaled, the client <em class="bcp14">MUST NOT</em> send any more requests on that connection.1589 </p> 1590 <h 4 id="rfc.section.7.1.2.1"><a href="#rfc.section.7.1.2.1">7.1.2.1</a> <a id="persistent.negotiation" href="#persistent.negotiation">Negotiation</a></h4>1591 <p id="rfc.section. 7.1.2.1.p.1">An HTTP/1.1 server <em class="bcp14">MAY</em> assume that a HTTP/1.1 client intends to maintain a persistent connection unless a Connection header including the connection-token1571 <p id="rfc.section.2.11.1.2.p.2">Persistent connections provide a mechanism by which a client and a server can signal the close of a TCP connection. This signaling 1572 takes place using the Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.2" title="Connection">Section 3.1</a>). Once a close has been signaled, the client <em class="bcp14">MUST NOT</em> send any more requests on that connection. 1573 </p> 1574 <h5 id="rfc.section.2.11.1.2.1"><a href="#rfc.section.2.11.1.2.1">2.11.1.2.1</a> <a id="persistent.negotiation" href="#persistent.negotiation">Negotiation</a></h5> 1575 <p id="rfc.section.2.11.1.2.1.p.1">An HTTP/1.1 server <em class="bcp14">MAY</em> assume that a HTTP/1.1 client intends to maintain a persistent connection unless a Connection header including the connection-token 1592 1576 "close" was sent in the request. If the server chooses to close the connection immediately after sending the response, it <em class="bcp14">SHOULD</em> send a Connection header including the connection-token close. 1593 1577 </p> 1594 <p id="rfc.section. 7.1.2.1.p.2">An HTTP/1.1 client <em class="bcp14">MAY</em> expect a connection to remain open, but would decide to keep it open based on whether the response from a server contains1578 <p id="rfc.section.2.11.1.2.1.p.2">An HTTP/1.1 client <em class="bcp14">MAY</em> expect a connection to remain open, but would decide to keep it open based on whether the response from a server contains 1595 1579 a Connection header with the connection-token close. In case the client does not want to maintain a connection for more than 1596 1580 that request, it <em class="bcp14">SHOULD</em> send a Connection header including the connection-token close. 1597 1581 </p> 1598 <p id="rfc.section. 7.1.2.1.p.3">If either the client or the server sends the close token in the Connection header, that request becomes the last one for the1582 <p id="rfc.section.2.11.1.2.1.p.3">If either the client or the server sends the close token in the Connection header, that request becomes the last one for the 1599 1583 connection. 1600 1584 </p> 1601 <p id="rfc.section. 7.1.2.1.p.4">Clients and servers <em class="bcp14">SHOULD NOT</em> assume that a persistent connection is maintained for HTTP versions less than 1.1 unless it is explicitly signaled. See <a href="#compatibility.with.http.1.0.persistent.connections" title="Compatibility with HTTP/1.0 Persistent Connections">Appendix B.2</a> for more information on backward compatibility with HTTP/1.0 clients.1602 </p> 1603 <p id="rfc.section. 7.1.2.1.p.5">In order to remain persistent, all messages on the connection <em class="bcp14">MUST</em> have a self-defined message length (i.e., one not defined by closure of the connection), as described in <a href="#message.length" title="Message Length">Section 3.4</a>.1604 </p> 1605 <h 4 id="rfc.section.7.1.2.2"><a href="#rfc.section.7.1.2.2">7.1.2.2</a> <a id="pipelining" href="#pipelining">Pipelining</a></h4>1606 <p id="rfc.section. 7.1.2.2.p.1">A client that supports persistent connections <em class="bcp14">MAY</em> "pipeline" its requests (i.e., send multiple requests without waiting for each response). A server <em class="bcp14">MUST</em> send its responses to those requests in the same order that the requests were received.1607 </p> 1608 <p id="rfc.section. 7.1.2.2.p.2">Clients which assume persistent connections and pipeline immediately after connection establishment <em class="bcp14">SHOULD</em> be prepared to retry their connection if the first pipelined attempt fails. If a client does such a retry, it <em class="bcp14">MUST NOT</em> pipeline before it knows the connection is persistent. Clients <em class="bcp14">MUST</em> also be prepared to resend their requests if the server closes the connection before sending all of the corresponding responses.1609 </p> 1610 <p id="rfc.section. 7.1.2.2.p.3">Clients <em class="bcp14">SHOULD NOT</em> pipeline requests using non-idempotent methods or non-idempotent sequences of methods (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 7.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.8"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Otherwise, a premature termination of the transport connection could lead to indeterminate results. A client wishing to1585 <p id="rfc.section.2.11.1.2.1.p.4">Clients and servers <em class="bcp14">SHOULD NOT</em> assume that a persistent connection is maintained for HTTP versions less than 1.1 unless it is explicitly signaled. See <a href="#compatibility.with.http.1.0.persistent.connections" title="Compatibility with HTTP/1.0 Persistent Connections">Appendix B.2</a> for more information on backward compatibility with HTTP/1.0 clients. 1586 </p> 1587 <p id="rfc.section.2.11.1.2.1.p.5">In order to remain persistent, all messages on the connection <em class="bcp14">MUST</em> have a self-defined message length (i.e., one not defined by closure of the connection), as described in <a href="#message.length" title="Message Length">Section 2.7.4</a>. 1588 </p> 1589 <h5 id="rfc.section.2.11.1.2.2"><a href="#rfc.section.2.11.1.2.2">2.11.1.2.2</a> <a id="pipelining" href="#pipelining">Pipelining</a></h5> 1590 <p id="rfc.section.2.11.1.2.2.p.1">A client that supports persistent connections <em class="bcp14">MAY</em> "pipeline" its requests (i.e., send multiple requests without waiting for each response). A server <em class="bcp14">MUST</em> send its responses to those requests in the same order that the requests were received. 1591 </p> 1592 <p id="rfc.section.2.11.1.2.2.p.2">Clients which assume persistent connections and pipeline immediately after connection establishment <em class="bcp14">SHOULD</em> be prepared to retry their connection if the first pipelined attempt fails. If a client does such a retry, it <em class="bcp14">MUST NOT</em> pipeline before it knows the connection is persistent. Clients <em class="bcp14">MUST</em> also be prepared to resend their requests if the server closes the connection before sending all of the corresponding responses. 1593 </p> 1594 <p id="rfc.section.2.11.1.2.2.p.3">Clients <em class="bcp14">SHOULD NOT</em> pipeline requests using non-idempotent methods or non-idempotent sequences of methods (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 7.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.8"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Otherwise, a premature termination of the transport connection could lead to indeterminate results. A client wishing to 1611 1595 send a non-idempotent request <em class="bcp14">SHOULD</em> wait to send that request until it has received the response status for the previous request. 1612 1596 </p> 1613 <h 3 id="rfc.section.7.1.3"><a href="#rfc.section.7.1.3">7.1.3</a> <a id="persistent.proxy" href="#persistent.proxy">Proxy Servers</a></h3>1614 <p id="rfc.section. 7.1.3.p.1">It is especially important that proxies correctly implement the properties of the Connection header field as specified in <a href="#header.connection" id="rfc.xref.header.connection.3" title="Connection">Section 8.1</a>.1615 </p> 1616 <p id="rfc.section. 7.1.3.p.2">The proxy server <em class="bcp14">MUST</em> signal persistent connections separately with its clients and the origin servers (or other proxy servers) that it connects1597 <h4 id="rfc.section.2.11.1.3"><a href="#rfc.section.2.11.1.3">2.11.1.3</a> <a id="persistent.proxy" href="#persistent.proxy">Proxy Servers</a></h4> 1598 <p id="rfc.section.2.11.1.3.p.1">It is especially important that proxies correctly implement the properties of the Connection header field as specified in <a href="#header.connection" id="rfc.xref.header.connection.3" title="Connection">Section 3.1</a>. 1599 </p> 1600 <p id="rfc.section.2.11.1.3.p.2">The proxy server <em class="bcp14">MUST</em> signal persistent connections separately with its clients and the origin servers (or other proxy servers) that it connects 1617 1601 to. Each persistent connection applies to only one transport link. 1618 1602 </p> 1619 <p id="rfc.section. 7.1.3.p.3">A proxy server <em class="bcp14">MUST NOT</em> establish a HTTP/1.1 persistent connection with an HTTP/1.0 client (but see <a href="http://tools.ietf.org/html/rfc2068#section-19.7.1">Section 19.7.1</a> of <a href="#RFC2068" id="rfc.xref.RFC2068.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> for information and discussion of the problems with the Keep-Alive header implemented by many HTTP/1.0 clients).1620 </p> 1621 <h 3 id="rfc.section.7.1.4"><a href="#rfc.section.7.1.4">7.1.4</a> <a id="persistent.practical" href="#persistent.practical">Practical Considerations</a></h3>1622 <p id="rfc.section. 7.1.4.p.1">Servers will usually have some time-out value beyond which they will no longer maintain an inactive connection. Proxy servers1603 <p id="rfc.section.2.11.1.3.p.3">A proxy server <em class="bcp14">MUST NOT</em> establish a HTTP/1.1 persistent connection with an HTTP/1.0 client (but see <a href="http://tools.ietf.org/html/rfc2068#section-19.7.1">Section 19.7.1</a> of <a href="#RFC2068" id="rfc.xref.RFC2068.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> for information and discussion of the problems with the Keep-Alive header implemented by many HTTP/1.0 clients). 1604 </p> 1605 <h4 id="rfc.section.2.11.1.4"><a href="#rfc.section.2.11.1.4">2.11.1.4</a> <a id="persistent.practical" href="#persistent.practical">Practical Considerations</a></h4> 1606 <p id="rfc.section.2.11.1.4.p.1">Servers will usually have some time-out value beyond which they will no longer maintain an inactive connection. Proxy servers 1623 1607 might make this a higher value since it is likely that the client will be making more connections through the same server. 1624 1608 The use of persistent connections places no requirements on the length (or existence) of this time-out for either the client 1625 1609 or the server. 1626 1610 </p> 1627 <p id="rfc.section. 7.1.4.p.2">When a client or server wishes to time-out it <em class="bcp14">SHOULD</em> issue a graceful close on the transport connection. Clients and servers <em class="bcp14">SHOULD</em> both constantly watch for the other side of the transport close, and respond to it as appropriate. If a client or server does1611 <p id="rfc.section.2.11.1.4.p.2">When a client or server wishes to time-out it <em class="bcp14">SHOULD</em> issue a graceful close on the transport connection. Clients and servers <em class="bcp14">SHOULD</em> both constantly watch for the other side of the transport close, and respond to it as appropriate. If a client or server does 1628 1612 not detect the other side's close promptly it could cause unnecessary resource drain on the network. 1629 1613 </p> 1630 <p id="rfc.section. 7.1.4.p.3">A client, server, or proxy <em class="bcp14">MAY</em> close the transport connection at any time. For example, a client might have started to send a new request at the same time1614 <p id="rfc.section.2.11.1.4.p.3">A client, server, or proxy <em class="bcp14">MAY</em> close the transport connection at any time. For example, a client might have started to send a new request at the same time 1631 1615 that the server has decided to close the "idle" connection. From the server's point of view, the connection is being closed 1632 1616 while it was idle, but from the client's point of view, a request is in progress. 1633 1617 </p> 1634 <p id="rfc.section. 7.1.4.p.4">This means that clients, servers, and proxies <em class="bcp14">MUST</em> be able to recover from asynchronous close events. Client software <em class="bcp14">SHOULD</em> reopen the transport connection and retransmit the aborted sequence of requests without user interaction so long as the request1618 <p id="rfc.section.2.11.1.4.p.4">This means that clients, servers, and proxies <em class="bcp14">MUST</em> be able to recover from asynchronous close events. Client software <em class="bcp14">SHOULD</em> reopen the transport connection and retransmit the aborted sequence of requests without user interaction so long as the request 1635 1619 sequence is idempotent (see <a href="p2-semantics.html#idempotent.methods" title="Idempotent Methods">Section 7.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.9"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). Non-idempotent methods or sequences <em class="bcp14">MUST NOT</em> be automatically retried, although user agents <em class="bcp14">MAY</em> offer a human operator the choice of retrying the request(s). Confirmation by user-agent software with semantic understanding 1636 1620 of the application <em class="bcp14">MAY</em> substitute for user confirmation. The automatic retry <em class="bcp14">SHOULD NOT</em> be repeated if the second sequence of requests fails. 1637 1621 </p> 1638 <p id="rfc.section. 7.1.4.p.5">Servers <em class="bcp14">SHOULD</em> always respond to at least one request per connection, if at all possible. Servers <em class="bcp14">SHOULD NOT</em> close a connection in the middle of transmitting a response, unless a network or client failure is suspected.1639 </p> 1640 <p id="rfc.section. 7.1.4.p.6">Clients that use persistent connections <em class="bcp14">SHOULD</em> limit the number of simultaneous connections that they maintain to a given server. A single-user client <em class="bcp14">SHOULD NOT</em> maintain more than 2 connections with any server or proxy. A proxy <em class="bcp14">SHOULD</em> use up to 2*N connections to another server or proxy, where N is the number of simultaneously active users. These guidelines1622 <p id="rfc.section.2.11.1.4.p.5">Servers <em class="bcp14">SHOULD</em> always respond to at least one request per connection, if at all possible. Servers <em class="bcp14">SHOULD NOT</em> close a connection in the middle of transmitting a response, unless a network or client failure is suspected. 1623 </p> 1624 <p id="rfc.section.2.11.1.4.p.6">Clients that use persistent connections <em class="bcp14">SHOULD</em> limit the number of simultaneous connections that they maintain to a given server. A single-user client <em class="bcp14">SHOULD NOT</em> maintain more than 2 connections with any server or proxy. A proxy <em class="bcp14">SHOULD</em> use up to 2*N connections to another server or proxy, where N is the number of simultaneously active users. These guidelines 1641 1625 are intended to improve HTTP response times and avoid congestion. 1642 1626 </p> 1643 <h 2 id="rfc.section.7.2"><a href="#rfc.section.7.2">7.2</a> <a id="message.transmission.requirements" href="#message.transmission.requirements">Message Transmission Requirements</a></h2>1644 <h 3 id="rfc.section.7.2.1"><a href="#rfc.section.7.2.1">7.2.1</a> <a id="persistent.flow" href="#persistent.flow">Persistent Connections and Flow Control</a></h3>1645 <p id="rfc.section. 7.2.1.p.1">HTTP/1.1 servers <em class="bcp14">SHOULD</em> maintain persistent connections and use TCP's flow control mechanisms to resolve temporary overloads, rather than terminating1627 <h3 id="rfc.section.2.11.2"><a href="#rfc.section.2.11.2">2.11.2</a> <a id="message.transmission.requirements" href="#message.transmission.requirements">Message Transmission Requirements</a></h3> 1628 <h4 id="rfc.section.2.11.2.1"><a href="#rfc.section.2.11.2.1">2.11.2.1</a> <a id="persistent.flow" href="#persistent.flow">Persistent Connections and Flow Control</a></h4> 1629 <p id="rfc.section.2.11.2.1.p.1">HTTP/1.1 servers <em class="bcp14">SHOULD</em> maintain persistent connections and use TCP's flow control mechanisms to resolve temporary overloads, rather than terminating 1646 1630 connections with the expectation that clients will retry. The latter technique can exacerbate network congestion. 1647 1631 </p> 1648 <h 3 id="rfc.section.7.2.2"><a href="#rfc.section.7.2.2">7.2.2</a> <a id="persistent.monitor" href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></h3>1649 <p id="rfc.section. 7.2.2.p.1">An HTTP/1.1 (or later) client sending a message-body <em class="bcp14">SHOULD</em> monitor the network connection for an error status while it is transmitting the request. If the client sees an error status,1650 it <em class="bcp14">SHOULD</em> immediately cease transmitting the body. If the body is being sent using a "chunked" encoding (<a href="#transfer.codings" title="Transfer Codings">Section 6.2</a>), a zero length chunk and empty trailer <em class="bcp14">MAY</em> be used to prematurely mark the end of the message. If the body was preceded by a Content-Length header, the client <em class="bcp14">MUST</em> close the connection.1651 </p> 1652 <h 3 id="rfc.section.7.2.3"><a href="#rfc.section.7.2.3">7.2.3</a> <a id="use.of.the.100.status" href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></h3>1653 <p id="rfc.section. 7.2.3.p.1">The purpose of the 100 (Continue) status (see <a href="p2-semantics.html#status.100" title="100 Continue">Section 8.1.1</a> of <a href="#Part2" id="rfc.xref.Part2.10"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) is to allow a client that is sending a request message with a request body to determine if the origin server is willing1632 <h4 id="rfc.section.2.11.2.2"><a href="#rfc.section.2.11.2.2">2.11.2.2</a> <a id="persistent.monitor" href="#persistent.monitor">Monitoring Connections for Error Status Messages</a></h4> 1633 <p id="rfc.section.2.11.2.2.p.1">An HTTP/1.1 (or later) client sending a message-body <em class="bcp14">SHOULD</em> monitor the network connection for an error status while it is transmitting the request. If the client sees an error status, 1634 it <em class="bcp14">SHOULD</em> immediately cease transmitting the body. If the body is being sent using a "chunked" encoding (<a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a>), a zero length chunk and empty trailer <em class="bcp14">MAY</em> be used to prematurely mark the end of the message. If the body was preceded by a Content-Length header, the client <em class="bcp14">MUST</em> close the connection. 1635 </p> 1636 <h4 id="rfc.section.2.11.2.3"><a href="#rfc.section.2.11.2.3">2.11.2.3</a> <a id="use.of.the.100.status" href="#use.of.the.100.status">Use of the 100 (Continue) Status</a></h4> 1637 <p id="rfc.section.2.11.2.3.p.1">The purpose of the 100 (Continue) status (see <a href="p2-semantics.html#status.100" title="100 Continue">Section 8.1.1</a> of <a href="#Part2" id="rfc.xref.Part2.10"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) is to allow a client that is sending a request message with a request body to determine if the origin server is willing 1654 1638 to accept the request (based on the request headers) before the client sends the request body. In some cases, it might either 1655 1639 be inappropriate or highly inefficient for the client to send the body if the server will reject the message without looking 1656 1640 at the body. 1657 1641 </p> 1658 <p id="rfc.section. 7.2.3.p.2">Requirements for HTTP/1.1 clients: </p>1642 <p id="rfc.section.2.11.2.3.p.2">Requirements for HTTP/1.1 clients: </p> 1659 1643 <ul> 1660 1644 <li>If a client will wait for a 100 (Continue) response before sending the request body, it <em class="bcp14">MUST</em> send an Expect request-header field (<a href="p2-semantics.html#header.expect" title="Expect">Section 9.2</a> of <a href="#Part2" id="rfc.xref.Part2.11"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>) with the "100-continue" expectation. … … 1663 1647 </li> 1664 1648 </ul> 1665 <p id="rfc.section. 7.2.3.p.3">Because of the presence of older implementations, the protocol allows ambiguous situations in which a client may send "Expect:1649 <p id="rfc.section.2.11.2.3.p.3">Because of the presence of older implementations, the protocol allows ambiguous situations in which a client may send "Expect: 1666 1650 100-continue" without receiving either a 417 (Expectation Failed) status or a 100 (Continue) status. Therefore, when a client 1667 1651 sends this header field to an origin server (possibly via a proxy) from which it has never seen a 100 (Continue) status, the 1668 1652 client <em class="bcp14">SHOULD NOT</em> wait for an indefinite period before sending the request body. 1669 1653 </p> 1670 <p id="rfc.section. 7.2.3.p.4">Requirements for HTTP/1.1 origin servers: </p>1654 <p id="rfc.section.2.11.2.3.p.4">Requirements for HTTP/1.1 origin servers: </p> 1671 1655 <ul> 1672 1656 <li>Upon receiving a request which includes an Expect request-header field with the "100-continue" expectation, an origin server <em class="bcp14">MUST</em> either respond with 100 (Continue) status and continue to read from the input stream, or respond with a final status code. … … 1692 1676 </li> 1693 1677 </ul> 1694 <p id="rfc.section. 7.2.3.p.5">Requirements for HTTP/1.1 proxies: </p>1678 <p id="rfc.section.2.11.2.3.p.5">Requirements for HTTP/1.1 proxies: </p> 1695 1679 <ul> 1696 1680 <li>If a proxy receives a request that includes an Expect request-header field with the "100-continue" expectation, and the proxy … … 1707 1691 </li> 1708 1692 </ul> 1709 <h 3 id="rfc.section.7.2.4"><a href="#rfc.section.7.2.4">7.2.4</a> <a id="connection.premature" href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></h3>1710 <p id="rfc.section. 7.2.4.p.1">If an HTTP/1.1 client sends a request which includes a request body, but which does not include an Expect request-header field1693 <h4 id="rfc.section.2.11.2.4"><a href="#rfc.section.2.11.2.4">2.11.2.4</a> <a id="connection.premature" href="#connection.premature">Client Behavior if Server Prematurely Closes Connection</a></h4> 1694 <p id="rfc.section.2.11.2.4.p.1">If an HTTP/1.1 client sends a request which includes a request body, but which does not include an Expect request-header field 1711 1695 with the "100-continue" expectation, and if the client is not directly connected to an HTTP/1.1 origin server, and if the 1712 1696 client sees the connection close before receiving any status from the server, the client <em class="bcp14">SHOULD</em> retry the request. If the client does retry this request, it <em class="bcp14">MAY</em> use the following "binary exponential backoff" algorithm to be assured of obtaining a reliable response: … … 1725 1709 </li> 1726 1710 </ol> 1727 <p id="rfc.section. 7.2.4.p.2">If at any point an error status is received, the client </p>1711 <p id="rfc.section.2.11.2.4.p.2">If at any point an error status is received, the client </p> 1728 1712 <ul> 1729 1713 <li><em class="bcp14">SHOULD NOT</em> continue and … … 1732 1716 </li> 1733 1717 </ul> 1734 <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a> <a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1> 1735 <p id="rfc.section.8.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to message framing and transport protocols.</p> 1736 <p id="rfc.section.8.p.2">For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who 1718 <h2 id="rfc.section.2.12"><a href="#rfc.section.2.12">2.12</a> <a id="misc" href="#misc">Miscellaneous notes that may disappear</a></h2> 1719 <h3 id="rfc.section.2.12.1"><a href="#rfc.section.2.12.1">2.12.1</a> <a id="scheme.aliases" href="#scheme.aliases">Scheme aliases considered harmful</a></h3> 1720 <p id="rfc.section.2.12.1.p.1"> <span class="comment" id="rfc.comment.2">[<a href="#rfc.comment.2" class="smpl">rfc.comment.2</a>: TBS: describe why aliases like webcal are harmful.]</span> 1721 </p> 1722 <h2 id="rfc.section.2.13"><a href="#rfc.section.2.13">2.13</a> <a id="http.proxy" href="#http.proxy">Use of HTTP for proxy communication</a></h2> 1723 <p id="rfc.section.2.13.p.1"> <span class="comment" id="rfc.comment.3">[<a href="#rfc.comment.3" class="smpl">rfc.comment.3</a>: TBD: Configured to use HTTP to proxy HTTP or other protocols.]</span> 1724 </p> 1725 <h2 id="rfc.section.2.14"><a href="#rfc.section.2.14">2.14</a> <a id="http.intercept" href="#http.intercept">Interception of HTTP for access control</a></h2> 1726 <p id="rfc.section.2.14.p.1"> <span class="comment" id="rfc.comment.4">[<a href="#rfc.comment.4" class="smpl">rfc.comment.4</a>: TBD: Interception of HTTP traffic for initiating access control.]</span> 1727 </p> 1728 <h2 id="rfc.section.2.15"><a href="#rfc.section.2.15">2.15</a> <a id="http.others" href="#http.others">Use of HTTP by other protocols</a></h2> 1729 <p id="rfc.section.2.15.p.1"> <span class="comment" id="rfc.comment.5">[<a href="#rfc.comment.5" class="smpl">rfc.comment.5</a>: TBD: Profiles of HTTP defined by other protocol. Extensions of HTTP like WebDAV.]</span> 1730 </p> 1731 <h2 id="rfc.section.2.16"><a href="#rfc.section.2.16">2.16</a> <a id="http.media" href="#http.media">Use of HTTP by media type specification</a></h2> 1732 <p id="rfc.section.2.16.p.1"> <span class="comment" id="rfc.comment.6">[<a href="#rfc.comment.6" class="smpl">rfc.comment.6</a>: TBD: Instructions on composing HTTP requests via hypertext formats.]</span> 1733 </p> 1734 <h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a> <a id="header.field.definitions" href="#header.field.definitions">Header Field Definitions</a></h1> 1735 <p id="rfc.section.3.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to message framing and transport protocols.</p> 1736 <p id="rfc.section.3.p.2">For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who 1737 1737 receives the entity. 1738 1738 </p> 1739 1739 <div id="rfc.iref.c.5"></div> 1740 1740 <div id="rfc.iref.h.6"></div> 1741 <h2 id="rfc.section. 8.1"><a href="#rfc.section.8.1">8.1</a> <a id="header.connection" href="#header.connection">Connection</a></h2>1742 <p id="rfc.section. 8.1.p.1">The general-header field "Connection" allows the sender to specify options that are desired for that particular connection1741 <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a> <a id="header.connection" href="#header.connection">Connection</a></h2> 1742 <p id="rfc.section.3.1.p.1">The general-header field "Connection" allows the sender to specify options that are desired for that particular connection 1743 1743 and <em class="bcp14">MUST NOT</em> be communicated by proxies over further connections. 1744 1744 </p> 1745 <p id="rfc.section. 8.1.p.2">The Connection header's value has the following grammar:</p>1745 <p id="rfc.section.3.1.p.2">The Connection header's value has the following grammar:</p> 1746 1746 <div id="rfc.figure.u.52"></div><pre class="inline"><span id="rfc.iref.g.89"></span><span id="rfc.iref.g.90"></span><span id="rfc.iref.g.91"></span> <a href="#header.connection" class="smpl">Connection</a> = "Connection" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.connection" class="smpl">Connection-v</a> 1747 1747 <a href="#header.connection" class="smpl">Connection-v</a> = 1#<a href="#header.connection" class="smpl">connection-token</a> 1748 1748 <a href="#header.connection" class="smpl">connection-token</a> = <a href="#rule.token.separators" class="smpl">token</a> 1749 </pre><p id="rfc.section. 8.1.p.4">HTTP/1.1 proxies <em class="bcp14">MUST</em> parse the Connection header field before a message is forwarded and, for each connection-token in this field, remove any header1749 </pre><p id="rfc.section.3.1.p.4">HTTP/1.1 proxies <em class="bcp14">MUST</em> parse the Connection header field before a message is forwarded and, for each connection-token in this field, remove any header 1750 1750 field(s) from the message with the same name as the connection-token. Connection options are signaled by the presence of a 1751 1751 connection-token in the Connection header field, not by any corresponding additional header field(s), since the additional 1752 1752 header field may not be sent if there are no parameters associated with that connection option. 1753 1753 </p> 1754 <p id="rfc.section. 8.1.p.5">Message headers listed in the Connection header <em class="bcp14">MUST NOT</em> include end-to-end headers, such as Cache-Control.1755 </p> 1756 <p id="rfc.section. 8.1.p.6">HTTP/1.1 defines the "close" connection option for the sender to signal that the connection will be closed after completion1754 <p id="rfc.section.3.1.p.5">Message headers listed in the Connection header <em class="bcp14">MUST NOT</em> include end-to-end headers, such as Cache-Control. 1755 </p> 1756 <p id="rfc.section.3.1.p.6">HTTP/1.1 defines the "close" connection option for the sender to signal that the connection will be closed after completion 1757 1757 of the response. For example, 1758 1758 </p> 1759 1759 <div id="rfc.figure.u.53"></div><pre class="text"> Connection: close 1760 </pre><p id="rfc.section. 8.1.p.8">in either the request or the response header fields indicates that the connection <em class="bcp14">SHOULD NOT</em> be considered `persistent' (<a href="#persistent.connections" title="Persistent Connections">Section 7.1</a>) after the current request/response is complete.1761 </p> 1762 <p id="rfc.section. 8.1.p.9">An HTTP/1.1 client that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every request message.1763 </p> 1764 <p id="rfc.section. 8.1.p.10">An HTTP/1.1 server that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every response message that does not have a 1xx (informational) status code.1765 </p> 1766 <p id="rfc.section. 8.1.p.11">A system receiving an HTTP/1.0 (or lower-version) message that includes a Connection header <em class="bcp14">MUST</em>, for each connection-token in this field, remove and ignore any header field(s) from the message with the same name as the1760 </pre><p id="rfc.section.3.1.p.8">in either the request or the response header fields indicates that the connection <em class="bcp14">SHOULD NOT</em> be considered `persistent' (<a href="#persistent.connections" title="Persistent Connections">Section 2.11.1</a>) after the current request/response is complete. 1761 </p> 1762 <p id="rfc.section.3.1.p.9">An HTTP/1.1 client that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every request message. 1763 </p> 1764 <p id="rfc.section.3.1.p.10">An HTTP/1.1 server that does not support persistent connections <em class="bcp14">MUST</em> include the "close" connection option in every response message that does not have a 1xx (informational) status code. 1765 </p> 1766 <p id="rfc.section.3.1.p.11">A system receiving an HTTP/1.0 (or lower-version) message that includes a Connection header <em class="bcp14">MUST</em>, for each connection-token in this field, remove and ignore any header field(s) from the message with the same name as the 1767 1767 connection-token. This protects against mistaken forwarding of such header fields by pre-HTTP/1.1 proxies. See <a href="#compatibility.with.http.1.0.persistent.connections" title="Compatibility with HTTP/1.0 Persistent Connections">Appendix B.2</a>. 1768 1768 </p> 1769 1769 <div id="rfc.iref.c.6"></div> 1770 1770 <div id="rfc.iref.h.7"></div> 1771 <h2 id="rfc.section. 8.2"><a href="#rfc.section.8.2">8.2</a> <a id="header.content-length" href="#header.content-length">Content-Length</a></h2>1772 <p id="rfc.section. 8.2.p.1">The entity-header field "Content-Length" indicates the size of the entity-body, in number of OCTETs, sent to the recipient1771 <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a> <a id="header.content-length" href="#header.content-length">Content-Length</a></h2> 1772 <p id="rfc.section.3.2.p.1">The entity-header field "Content-Length" indicates the size of the entity-body, in number of OCTETs, sent to the recipient 1773 1773 or, in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET. 1774 1774 </p> 1775 1775 <div id="rfc.figure.u.54"></div><pre class="inline"><span id="rfc.iref.g.92"></span><span id="rfc.iref.g.93"></span> <a href="#header.content-length" class="smpl">Content-Length</a> = "Content-Length" ":" <a href="#rule.whitespace" class="smpl">OWS</a> 1*<a href="#header.content-length" class="smpl">Content-Length-v</a> 1776 1776 <a href="#header.content-length" class="smpl">Content-Length-v</a> = 1*<a href="#core.rules" class="smpl">DIGIT</a> 1777 </pre><p id="rfc.section. 8.2.p.3">An example is</p>1777 </pre><p id="rfc.section.3.2.p.3">An example is</p> 1778 1778 <div id="rfc.figure.u.55"></div><pre class="text"> Content-Length: 3495 1779 </pre><p id="rfc.section. 8.2.p.5">Applications <em class="bcp14">SHOULD</em> use this field to indicate the transfer-length of the message-body, unless this is prohibited by the rules in <a href="#message.length" title="Message Length">Section 3.4</a>.1780 </p> 1781 <p id="rfc.section. 8.2.p.6">Any Content-Length greater than or equal to zero is a valid value. <a href="#message.length" title="Message Length">Section 3.4</a> describes how to determine the length of a message-body if a Content-Length is not given.1782 </p> 1783 <p id="rfc.section. 8.2.p.7">Note that the meaning of this field is significantly different from the corresponding definition in MIME, where it is an optional1779 </pre><p id="rfc.section.3.2.p.5">Applications <em class="bcp14">SHOULD</em> use this field to indicate the transfer-length of the message-body, unless this is prohibited by the rules in <a href="#message.length" title="Message Length">Section 2.7.4</a>. 1780 </p> 1781 <p id="rfc.section.3.2.p.6">Any Content-Length greater than or equal to zero is a valid value. <a href="#message.length" title="Message Length">Section 2.7.4</a> describes how to determine the length of a message-body if a Content-Length is not given. 1782 </p> 1783 <p id="rfc.section.3.2.p.7">Note that the meaning of this field is significantly different from the corresponding definition in MIME, where it is an optional 1784 1784 field used within the "message/external-body" content-type. In HTTP, it <em class="bcp14">SHOULD</em> be sent whenever the message's length can be determined prior to being transferred, unless this is prohibited by the rules 1785 in <a href="#message.length" title="Message Length">Section 3.4</a>.1785 in <a href="#message.length" title="Message Length">Section 2.7.4</a>. 1786 1786 </p> 1787 1787 <div id="rfc.iref.d.2"></div> 1788 1788 <div id="rfc.iref.h.8"></div> 1789 <h2 id="rfc.section. 8.3"><a href="#rfc.section.8.3">8.3</a> <a id="header.date" href="#header.date">Date</a></h2>1790 <p id="rfc.section. 8.3.p.1">The general-header field "Date" represents the date and time at which the message was originated, having the same semantics1791 as orig-date in <a href="http://tools.ietf.org/html/rfc5322#section-3.6.1">Section 3.6.1</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as described in <a href="#date.time.formats.full.date" title="Date/Time Formats: Full Date">Section 6.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format.1789 <h2 id="rfc.section.3.3"><a href="#rfc.section.3.3">3.3</a> <a id="header.date" href="#header.date">Date</a></h2> 1790 <p id="rfc.section.3.3.p.1">The general-header field "Date" represents the date and time at which the message was originated, having the same semantics 1791 as orig-date in <a href="http://tools.ietf.org/html/rfc5322#section-3.6.1">Section 3.6.1</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.4"><cite title="Internet Message Format">[RFC5322]</cite></a>. The field value is an HTTP-date, as described in <a href="#date.time.formats.full.date" title="Date/Time Formats: Full Date">Section 2.10.1</a>; it <em class="bcp14">MUST</em> be sent in rfc1123-date format. 1792 1792 </p> 1793 1793 <div id="rfc.figure.u.56"></div><pre class="inline"><span id="rfc.iref.g.94"></span><span id="rfc.iref.g.95"></span> <a href="#header.date" class="smpl">Date</a> = "Date" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.date" class="smpl">Date-v</a> 1794 1794 <a href="#header.date" class="smpl">Date-v</a> = <a href="#date.time.formats.full.date" class="smpl">HTTP-date</a> 1795 </pre><p id="rfc.section. 8.3.p.3">An example is</p>1795 </pre><p id="rfc.section.3.3.p.3">An example is</p> 1796 1796 <div id="rfc.figure.u.57"></div><pre class="text"> Date: Tue, 15 Nov 1994 08:12:31 GMT 1797 </pre><p id="rfc.section. 8.3.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases:1797 </pre><p id="rfc.section.3.3.p.5">Origin servers <em class="bcp14">MUST</em> include a Date header field in all responses, except in these cases: 1798 1798 </p> 1799 1799 <ol> … … 1803 1803 is inconvenient or impossible to generate a valid Date. 1804 1804 </li> 1805 <li>If the server does not have a clock that can provide a reasonable approximation of the current time, its responses <em class="bcp14">MUST NOT</em> include a Date header field. In this case, the rules in <a href="#clockless.origin.server.operation" title="Clockless Origin Server Operation">Section 8.3.1</a> <em class="bcp14">MUST</em> be followed.1805 <li>If the server does not have a clock that can provide a reasonable approximation of the current time, its responses <em class="bcp14">MUST NOT</em> include a Date header field. In this case, the rules in <a href="#clockless.origin.server.operation" title="Clockless Origin Server Operation">Section 3.3.1</a> <em class="bcp14">MUST</em> be followed. 1806 1806 </li> 1807 1807 </ol> 1808 <p id="rfc.section. 8.3.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient or gatewayed via a protocol which requires1808 <p id="rfc.section.3.3.p.6">A received message that does not have a Date header field <em class="bcp14">MUST</em> be assigned one by the recipient if the message will be cached by that recipient or gatewayed via a protocol which requires 1809 1809 a Date. An HTTP implementation without a clock <em class="bcp14">MUST NOT</em> cache responses without revalidating them on every use. An HTTP cache, especially a shared cache, <em class="bcp14">SHOULD</em> use a mechanism, such as NTP <a href="#RFC1305" id="rfc.xref.RFC1305.1"><cite title="Network Time Protocol (Version 3) Specification, Implementation">[RFC1305]</cite></a>, to synchronize its clock with a reliable external standard. 1810 1810 </p> 1811 <p id="rfc.section. 8.3.p.7">Clients <em class="bcp14">SHOULD</em> only send a Date header field in messages that include an entity-body, as in the case of the PUT and POST requests, and even1811 <p id="rfc.section.3.3.p.7">Clients <em class="bcp14">SHOULD</em> only send a Date header field in messages that include an entity-body, as in the case of the PUT and POST requests, and even 1812 1812 then it is optional. A client without a clock <em class="bcp14">MUST NOT</em> send a Date header field in a request. 1813 1813 </p> 1814 <p id="rfc.section. 8.3.p.8">The HTTP-date sent in a Date header <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means1814 <p id="rfc.section.3.3.p.8">The HTTP-date sent in a Date header <em class="bcp14">SHOULD NOT</em> represent a date and time subsequent to the generation of the message. It <em class="bcp14">SHOULD</em> represent the best available approximation of the date and time of message generation, unless the implementation has no means 1815 1815 of generating a reasonably accurate date and time. In theory, the date ought to represent the moment just before the entity 1816 1816 is generated. In practice, the date can be generated at any time during the message origination without affecting its semantic 1817 1817 value. 1818 1818 </p> 1819 <h3 id="rfc.section. 8.3.1"><a href="#rfc.section.8.3.1">8.3.1</a> <a id="clockless.origin.server.operation" href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></h3>1820 <p id="rfc.section. 8.3.1.p.1">Some origin server implementations might not have a clock available. An origin server without a clock <em class="bcp14">MUST NOT</em> assign Expires or Last-Modified values to a response, unless these values were associated with the resource by a system or1819 <h3 id="rfc.section.3.3.1"><a href="#rfc.section.3.3.1">3.3.1</a> <a id="clockless.origin.server.operation" href="#clockless.origin.server.operation">Clockless Origin Server Operation</a></h3> 1820 <p id="rfc.section.3.3.1.p.1">Some origin server implementations might not have a clock available. An origin server without a clock <em class="bcp14">MUST NOT</em> assign Expires or Last-Modified values to a response, unless these values were associated with the resource by a system or 1821 1821 user with a reliable clock. It <em class="bcp14">MAY</em> assign an Expires value that is known, at or before server configuration time, to be in the past (this allows "pre-expiration" 1822 1822 of responses without storing separate Expires values for each resource). … … 1824 1824 <div id="rfc.iref.h.9"></div> 1825 1825 <div id="rfc.iref.h.10"></div> 1826 <h2 id="rfc.section. 8.4"><a href="#rfc.section.8.4">8.4</a> <a id="header.host" href="#header.host">Host</a></h2>1827 <p id="rfc.section. 8.4.p.1">The request-header field "Host" specifies the Internet host and port number of the resource being requested, as obtained from1826 <h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a> <a id="header.host" href="#header.host">Host</a></h2> 1827 <p id="rfc.section.3.4.p.1">The request-header field "Host" specifies the Internet host and port number of the resource being requested, as obtained from 1828 1828 the original URI given by the user or referring resource (generally an http URI, as described in <a href="#http.uri" title="http URI scheme">Section 2.6.1</a>). The Host field value <em class="bcp14">MUST</em> represent the naming authority of the origin server or gateway given by the original URL. This allows the origin server or 1829 1829 gateway to differentiate between internally-ambiguous URLs, such as the root "/" URL of a server for multiple host names on … … 1832 1832 <div id="rfc.figure.u.58"></div><pre class="inline"><span id="rfc.iref.g.96"></span><span id="rfc.iref.g.97"></span> <a href="#header.host" class="smpl">Host</a> = "Host" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.host" class="smpl">Host-v</a> 1833 1833 <a href="#header.host" class="smpl">Host-v</a> = <a href="#uri" class="smpl">uri-host</a> [ ":" <a href="#uri" class="smpl">port</a> ] ; <a href="#http.uri" title="http URI scheme">Section 2.6.1</a> 1834 </pre><p id="rfc.section. 8.4.p.3">A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an HTTP1834 </pre><p id="rfc.section.3.4.p.3">A "host" without any trailing port information implies the default port for the service requested (e.g., "80" for an HTTP 1835 1835 URL). For example, a request on the origin server for <http://www.example.org/pub/WWW/> would properly include: 1836 1836 </p> 1837 1837 <div id="rfc.figure.u.59"></div><pre class="text"> GET /pub/WWW/ HTTP/1.1 1838 1838 Host: www.example.org 1839 </pre><p id="rfc.section. 8.4.p.5">A client <em class="bcp14">MUST</em> include a Host header field in all HTTP/1.1 request messages. If the requested URI does not include an Internet host name1839 </pre><p id="rfc.section.3.4.p.5">A client <em class="bcp14">MUST</em> include a Host header field in all HTTP/1.1 request messages. If the requested URI does not include an Internet host name 1840 1840 for the service being requested, then the Host header field <em class="bcp14">MUST</em> be given with an empty value. An HTTP/1.1 proxy <em class="bcp14">MUST</em> ensure that any request message it forwards does contain an appropriate Host header field that identifies the service being 1841 1841 requested by the proxy. All Internet-based HTTP/1.1 servers <em class="bcp14">MUST</em> respond with a 400 (Bad Request) status code to any HTTP/1.1 request message which lacks a Host header field. 1842 1842 </p> 1843 <p id="rfc.section. 8.4.p.6">See Sections <a href="#the.resource.identified.by.a.request" title="The Resource Identified by a Request">4.2</a> and <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">B.1.1</a> for other requirements relating to Host.1843 <p id="rfc.section.3.4.p.6">See Sections <a href="#the.resource.identified.by.a.request" title="The Resource Identified by a Request">2.8.2</a> and <a href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" title="Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses">B.1.1</a> for other requirements relating to Host. 1844 1844 </p> 1845 1845 <div id="rfc.iref.t.2"></div> 1846 1846 <div id="rfc.iref.h.11"></div> 1847 <h2 id="rfc.section. 8.5"><a href="#rfc.section.8.5">8.5</a> <a id="header.te" href="#header.te">TE</a></h2>1848 <p id="rfc.section. 8.5.p.1">The request-header field "TE" indicates what extension transfer-codings it is willing to accept in the response and whether1847 <h2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a> <a id="header.te" href="#header.te">TE</a></h2> 1848 <p id="rfc.section.3.5.p.1">The request-header field "TE" indicates what extension transfer-codings it is willing to accept in the response and whether 1849 1849 or not it is willing to accept trailer fields in a chunked transfer-coding. Its value may consist of the keyword "trailers" 1850 and/or a comma-separated list of extension transfer-coding names with optional accept parameters (as described in <a href="#transfer.codings" title="Transfer Codings">Section 6.2</a>).1850 and/or a comma-separated list of extension transfer-coding names with optional accept parameters (as described in <a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a>). 1851 1851 </p> 1852 1852 <div id="rfc.figure.u.60"></div><pre class="inline"><span id="rfc.iref.g.98"></span><span id="rfc.iref.g.99"></span><span id="rfc.iref.g.100"></span><span id="rfc.iref.g.101"></span><span id="rfc.iref.g.102"></span> <a href="#header.te" class="smpl">TE</a> = "TE" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.te" class="smpl">TE-v</a> … … 1855 1855 <a href="#header.te" class="smpl">te-params</a> = <a href="#rule.whitespace" class="smpl">OWS</a> ";" <a href="#rule.whitespace" class="smpl">OWS</a> "q=" <a href="#quality.values" class="smpl">qvalue</a> *( <a href="#header.te" class="smpl">te-ext</a> ) 1856 1856 <a href="#header.te" class="smpl">te-ext</a> = <a href="#rule.whitespace" class="smpl">OWS</a> ";" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#rule.token.separators" class="smpl">token</a> [ "=" ( <a href="#rule.token.separators" class="smpl">token</a> / <a href="#rule.quoted-string" class="smpl">quoted-string</a> ) ] 1857 </pre><p id="rfc.section. 8.5.p.3">The presence of the keyword "trailers" indicates that the client is willing to accept trailer fields in a chunked transfer-coding,1858 as defined in <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 6.2.1</a>. This keyword is reserved for use with transfer-coding values even though it does not itself represent a transfer-coding.1859 </p> 1860 <p id="rfc.section. 8.5.p.4">Examples of its use are:</p>1857 </pre><p id="rfc.section.3.5.p.3">The presence of the keyword "trailers" indicates that the client is willing to accept trailer fields in a chunked transfer-coding, 1858 as defined in <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 2.10.2.1</a>. This keyword is reserved for use with transfer-coding values even though it does not itself represent a transfer-coding. 1859 </p> 1860 <p id="rfc.section.3.5.p.4">Examples of its use are:</p> 1861 1861 <div id="rfc.figure.u.61"></div><pre class="text"> TE: deflate 1862 1862 TE: 1863 1863 TE: trailers, deflate;q=0.5 1864 </pre><p id="rfc.section. 8.5.p.6">The TE header field only applies to the immediate connection. Therefore, the keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.4" title="Connection">Section 8.1</a>) whenever TE is present in an HTTP/1.1 message.1865 </p> 1866 <p id="rfc.section. 8.5.p.7">A server tests whether a transfer-coding is acceptable, according to a TE field, using these rules: </p>1864 </pre><p id="rfc.section.3.5.p.6">The TE header field only applies to the immediate connection. Therefore, the keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.4" title="Connection">Section 3.1</a>) whenever TE is present in an HTTP/1.1 message. 1865 </p> 1866 <p id="rfc.section.3.5.p.7">A server tests whether a transfer-coding is acceptable, according to a TE field, using these rules: </p> 1867 1867 <ol> 1868 1868 <li> … … 1878 1878 <li> 1879 1879 <p>If the transfer-coding being tested is one of the transfer-codings listed in the TE field, then it is acceptable unless it 1880 is accompanied by a qvalue of 0. (As defined in <a href="#quality.values" title="Quality Values">Section 6.4</a>, a qvalue of 0 means "not acceptable.")1880 is accompanied by a qvalue of 0. (As defined in <a href="#quality.values" title="Quality Values">Section 2.10.4</a>, a qvalue of 0 means "not acceptable.") 1881 1881 </p> 1882 1882 </li> … … 1887 1887 </li> 1888 1888 </ol> 1889 <p id="rfc.section. 8.5.p.8">If the TE field-value is empty or if no TE field is present, the only transfer-coding is "chunked". A message with no transfer-coding1889 <p id="rfc.section.3.5.p.8">If the TE field-value is empty or if no TE field is present, the only transfer-coding is "chunked". A message with no transfer-coding 1890 1890 is always acceptable. 1891 1891 </p> 1892 1892 <div id="rfc.iref.t.3"></div> 1893 1893 <div id="rfc.iref.h.12"></div> 1894 <h2 id="rfc.section. 8.6"><a href="#rfc.section.8.6">8.6</a> <a id="header.trailer" href="#header.trailer">Trailer</a></h2>1895 <p id="rfc.section. 8.6.p.1">The general field "Trailer" indicates that the given set of header fields is present in the trailer of a message encoded with1894 <h2 id="rfc.section.3.6"><a href="#rfc.section.3.6">3.6</a> <a id="header.trailer" href="#header.trailer">Trailer</a></h2> 1895 <p id="rfc.section.3.6.p.1">The general field "Trailer" indicates that the given set of header fields is present in the trailer of a message encoded with 1896 1896 chunked transfer-coding. 1897 1897 </p> 1898 1898 <div id="rfc.figure.u.62"></div><pre class="inline"><span id="rfc.iref.g.103"></span><span id="rfc.iref.g.104"></span> <a href="#header.trailer" class="smpl">Trailer</a> = "Trailer" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.trailer" class="smpl">Trailer-v</a> 1899 1899 <a href="#header.trailer" class="smpl">Trailer-v</a> = 1#<a href="#header.fields" class="smpl">field-name</a> 1900 </pre><p id="rfc.section. 8.6.p.3">An HTTP/1.1 message <em class="bcp14">SHOULD</em> include a Trailer header field in a message using chunked transfer-coding with a non-empty trailer. Doing so allows the recipient1900 </pre><p id="rfc.section.3.6.p.3">An HTTP/1.1 message <em class="bcp14">SHOULD</em> include a Trailer header field in a message using chunked transfer-coding with a non-empty trailer. Doing so allows the recipient 1901 1901 to know which header fields to expect in the trailer. 1902 1902 </p> 1903 <p id="rfc.section. 8.6.p.4">If no Trailer header field is present, the trailer <em class="bcp14">SHOULD NOT</em> include any header fields. See <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 6.2.1</a> for restrictions on the use of trailer fields in a "chunked" transfer-coding.1904 </p> 1905 <p id="rfc.section. 8.6.p.5">Message header fields listed in the Trailer header field <em class="bcp14">MUST NOT</em> include the following header fields:1903 <p id="rfc.section.3.6.p.4">If no Trailer header field is present, the trailer <em class="bcp14">SHOULD NOT</em> include any header fields. See <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 2.10.2.1</a> for restrictions on the use of trailer fields in a "chunked" transfer-coding. 1904 </p> 1905 <p id="rfc.section.3.6.p.5">Message header fields listed in the Trailer header field <em class="bcp14">MUST NOT</em> include the following header fields: 1906 1906 </p> 1907 1907 <ul> … … 1912 1912 <div id="rfc.iref.t.4"></div> 1913 1913 <div id="rfc.iref.h.13"></div> 1914 <h2 id="rfc.section. 8.7"><a href="#rfc.section.8.7">8.7</a> <a id="header.transfer-encoding" href="#header.transfer-encoding">Transfer-Encoding</a></h2>1915 <p id="rfc.section. 8.7.p.1">The general-header "Transfer-Encoding" field indicates what (if any) type of transformation has been applied to the message1914 <h2 id="rfc.section.3.7"><a href="#rfc.section.3.7">3.7</a> <a id="header.transfer-encoding" href="#header.transfer-encoding">Transfer-Encoding</a></h2> 1915 <p id="rfc.section.3.7.p.1">The general-header "Transfer-Encoding" field indicates what (if any) type of transformation has been applied to the message 1916 1916 body in order to safely transfer it between the sender and the recipient. This differs from the content-coding in that the 1917 1917 transfer-coding is a property of the message, not of the entity. … … 1920 1920 <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding-v</a> 1921 1921 <a href="#header.transfer-encoding" class="smpl">Transfer-Encoding-v</a> = 1#<a href="#transfer.codings" class="smpl">transfer-coding</a> 1922 </pre><p id="rfc.section. 8.7.p.3">Transfer-codings are defined in <a href="#transfer.codings" title="Transfer Codings">Section 6.2</a>. An example is:1922 </pre><p id="rfc.section.3.7.p.3">Transfer-codings are defined in <a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a>. An example is: 1923 1923 </p> 1924 1924 <div id="rfc.figure.u.64"></div><pre class="text"> Transfer-Encoding: chunked 1925 </pre><p id="rfc.section. 8.7.p.5">If multiple encodings have been applied to an entity, the transfer-codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other entity-header fields not defined by this specification.1926 </p> 1927 <p id="rfc.section. 8.7.p.6">Many older HTTP/1.0 applications do not understand the Transfer-Encoding header.</p>1925 </pre><p id="rfc.section.3.7.p.5">If multiple encodings have been applied to an entity, the transfer-codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other entity-header fields not defined by this specification. 1926 </p> 1927 <p id="rfc.section.3.7.p.6">Many older HTTP/1.0 applications do not understand the Transfer-Encoding header.</p> 1928 1928 <div id="rfc.iref.u.5"></div> 1929 1929 <div id="rfc.iref.h.14"></div> 1930 <h2 id="rfc.section. 8.8"><a href="#rfc.section.8.8">8.8</a> <a id="header.upgrade" href="#header.upgrade">Upgrade</a></h2>1931 <p id="rfc.section. 8.8.p.1">The general-header "Upgrade" allows the client to specify what additional communication protocols it supports and would like1930 <h2 id="rfc.section.3.8"><a href="#rfc.section.3.8">3.8</a> <a id="header.upgrade" href="#header.upgrade">Upgrade</a></h2> 1931 <p id="rfc.section.3.8.p.1">The general-header "Upgrade" allows the client to specify what additional communication protocols it supports and would like 1932 1932 to use if the server finds it appropriate to switch protocols. The server <em class="bcp14">MUST</em> use the Upgrade header field within a 101 (Switching Protocols) response to indicate which protocol(s) are being switched. 1933 1933 </p> 1934 1934 <div id="rfc.figure.u.65"></div><pre class="inline"><span id="rfc.iref.g.107"></span><span id="rfc.iref.g.108"></span> <a href="#header.upgrade" class="smpl">Upgrade</a> = "Upgrade" ":" <a href="#rule.whitespace" class="smpl">OWS</a> <a href="#header.upgrade" class="smpl">Upgrade-v</a> 1935 1935 <a href="#header.upgrade" class="smpl">Upgrade-v</a> = 1#<a href="#product.tokens" class="smpl">product</a> 1936 </pre><p id="rfc.section. 8.8.p.3">For example,</p>1936 </pre><p id="rfc.section.3.8.p.3">For example,</p> 1937 1937 <div id="rfc.figure.u.66"></div><pre class="text"> Upgrade: HTTP/2.0, SHTTP/1.3, IRC/6.9, RTA/x11 1938 </pre><p id="rfc.section. 8.8.p.5">The Upgrade header field is intended to provide a simple mechanism for transition from HTTP/1.1 to some other, incompatible1938 </pre><p id="rfc.section.3.8.p.5">The Upgrade header field is intended to provide a simple mechanism for transition from HTTP/1.1 to some other, incompatible 1939 1939 protocol. It does so by allowing the client to advertise its desire to use another protocol, such as a later version of HTTP 1940 1940 with a higher major version number, even though the current request has been made using HTTP/1.1. This eases the difficult … … 1943 1943 the server, possibly according to the nature of the method and/or resource being requested). 1944 1944 </p> 1945 <p id="rfc.section. 8.8.p.6">The Upgrade header field only applies to switching application-layer protocols upon the existing transport-layer connection.1945 <p id="rfc.section.3.8.p.6">The Upgrade header field only applies to switching application-layer protocols upon the existing transport-layer connection. 1946 1946 Upgrade cannot be used to insist on a protocol change; its acceptance and use by the server is optional. The capabilities 1947 1947 and nature of the application-layer communication after the protocol change is entirely dependent upon the new protocol chosen, 1948 1948 although the first action after changing the protocol <em class="bcp14">MUST</em> be a response to the initial HTTP request containing the Upgrade header field. 1949 1949 </p> 1950 <p id="rfc.section. 8.8.p.7">The Upgrade header field only applies to the immediate connection. Therefore, the upgrade keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.5" title="Connection">Section 8.1</a>) whenever Upgrade is present in an HTTP/1.1 message.1951 </p> 1952 <p id="rfc.section. 8.8.p.8">The Upgrade header field cannot be used to indicate a switch to a protocol on a different connection. For that purpose, it1950 <p id="rfc.section.3.8.p.7">The Upgrade header field only applies to the immediate connection. Therefore, the upgrade keyword <em class="bcp14">MUST</em> be supplied within a Connection header field (<a href="#header.connection" id="rfc.xref.header.connection.5" title="Connection">Section 3.1</a>) whenever Upgrade is present in an HTTP/1.1 message. 1951 </p> 1952 <p id="rfc.section.3.8.p.8">The Upgrade header field cannot be used to indicate a switch to a protocol on a different connection. For that purpose, it 1953 1953 is more appropriate to use a 301, 302, 303, or 305 redirection response. 1954 1954 </p> 1955 <p id="rfc.section. 8.8.p.9">This specification only defines the protocol name "HTTP" for use by the family of Hypertext Transfer Protocols, as defined1955 <p id="rfc.section.3.8.p.9">This specification only defines the protocol name "HTTP" for use by the family of Hypertext Transfer Protocols, as defined 1956 1956 by the HTTP version rules of <a href="#http.version" title="HTTP Version">Section 2.5</a> and future updates to this specification. Any token can be used as a protocol name; however, it will only be useful if both 1957 1957 the client and server associate the name with the same protocol. … … 1959 1959 <div id="rfc.iref.v.1"></div> 1960 1960 <div id="rfc.iref.h.15"></div> 1961 <h2 id="rfc.section. 8.9"><a href="#rfc.section.8.9">8.9</a> <a id="header.via" href="#header.via">Via</a></h2>1962 <p id="rfc.section. 8.9.p.1">The general-header field "Via" <em class="bcp14">MUST</em> be used by gateways and proxies to indicate the intermediate protocols and recipients between the user agent and the server1961 <h2 id="rfc.section.3.9"><a href="#rfc.section.3.9">3.9</a> <a id="header.via" href="#header.via">Via</a></h2> 1962 <p id="rfc.section.3.9.p.1">The general-header field "Via" <em class="bcp14">MUST</em> be used by gateways and proxies to indicate the intermediate protocols and recipients between the user agent and the server 1963 1963 on requests, and between the origin server and the client on responses. It is analogous to the "Received" field defined in <a href="http://tools.ietf.org/html/rfc5322#section-3.6.7">Section 3.6.7</a> of <a href="#RFC5322" id="rfc.xref.RFC5322.5"><cite title="Internet Message Format">[RFC5322]</cite></a> and is intended to be used for tracking message forwards, avoiding request loops, and identifying the protocol capabilities 1964 1964 of all senders along the request/response chain. … … 1972 1972 <a href="#header.via" class="smpl">received-by</a> = ( <a href="#uri" class="smpl">uri-host</a> [ ":" <a href="#uri" class="smpl">port</a> ] ) / <a href="#header.via" class="smpl">pseudonym</a> 1973 1973 <a href="#header.via" class="smpl">pseudonym</a> = <a href="#rule.token.separators" class="smpl">token</a> 1974 </pre><p id="rfc.section. 8.9.p.3">The received-protocol indicates the protocol version of the message received by the server or client along each segment of1974 </pre><p id="rfc.section.3.9.p.3">The received-protocol indicates the protocol version of the message received by the server or client along each segment of 1975 1975 the request/response chain. The received-protocol version is appended to the Via field value when the message is forwarded 1976 1976 so that information about the protocol capabilities of upstream applications remains visible to all recipients. 1977 1977 </p> 1978 <p id="rfc.section. 8.9.p.4">The protocol-name is optional if and only if it would be "HTTP". The received-by field is normally the host and optional port1978 <p id="rfc.section.3.9.p.4">The protocol-name is optional if and only if it would be "HTTP". The received-by field is normally the host and optional port 1979 1979 number of a recipient server or client that subsequently forwarded the message. However, if the real host is considered to 1980 1980 be sensitive information, it <em class="bcp14">MAY</em> be replaced by a pseudonym. If the port is not given, it <em class="bcp14">MAY</em> be assumed to be the default port of the received-protocol. 1981 1981 </p> 1982 <p id="rfc.section. 8.9.p.5">Multiple Via field values represents each proxy or gateway that has forwarded the message. Each recipient <em class="bcp14">MUST</em> append its information such that the end result is ordered according to the sequence of forwarding applications.1983 </p> 1984 <p id="rfc.section. 8.9.p.6">Comments <em class="bcp14">MAY</em> be used in the Via header field to identify the software of the recipient proxy or gateway, analogous to the User-Agent and1982 <p id="rfc.section.3.9.p.5">Multiple Via field values represents each proxy or gateway that has forwarded the message. Each recipient <em class="bcp14">MUST</em> append its information such that the end result is ordered according to the sequence of forwarding applications. 1983 </p> 1984 <p id="rfc.section.3.9.p.6">Comments <em class="bcp14">MAY</em> be used in the Via header field to identify the software of the recipient proxy or gateway, analogous to the User-Agent and 1985 1985 Server header fields. However, all comments in the Via field are optional and <em class="bcp14">MAY</em> be removed by any recipient prior to forwarding the message. 1986 1986 </p> 1987 <p id="rfc.section. 8.9.p.7">For example, a request message could be sent from an HTTP/1.0 user agent to an internal proxy code-named "fred", which uses1987 <p id="rfc.section.3.9.p.7">For example, a request message could be sent from an HTTP/1.0 user agent to an internal proxy code-named "fred", which uses 1988 1988 HTTP/1.1 to forward the request to a public proxy at p.example.net, which completes the request by forwarding it to the origin 1989 1989 server at www.example.com. The request received by www.example.com would then have the following Via header field: 1990 1990 </p> 1991 1991 <div id="rfc.figure.u.68"></div><pre class="text"> Via: 1.0 fred, 1.1 p.example.net (Apache/1.1) 1992 </pre><p id="rfc.section. 8.9.p.9">Proxies and gateways used as a portal through a network firewall <em class="bcp14">SHOULD NOT</em>, by default, forward the names and ports of hosts within the firewall region. This information <em class="bcp14">SHOULD</em> only be propagated if explicitly enabled. If not enabled, the received-by host of any host behind the firewall <em class="bcp14">SHOULD</em> be replaced by an appropriate pseudonym for that host.1993 </p> 1994 <p id="rfc.section. 8.9.p.10">For organizations that have strong privacy requirements for hiding internal structures, a proxy <em class="bcp14">MAY</em> combine an ordered subsequence of Via header field entries with identical received-protocol values into a single such entry.1992 </pre><p id="rfc.section.3.9.p.9">Proxies and gateways used as a portal through a network firewall <em class="bcp14">SHOULD NOT</em>, by default, forward the names and ports of hosts within the firewall region. This information <em class="bcp14">SHOULD</em> only be propagated if explicitly enabled. If not enabled, the received-by host of any host behind the firewall <em class="bcp14">SHOULD</em> be replaced by an appropriate pseudonym for that host. 1993 </p> 1994 <p id="rfc.section.3.9.p.10">For organizations that have strong privacy requirements for hiding internal structures, a proxy <em class="bcp14">MAY</em> combine an ordered subsequence of Via header field entries with identical received-protocol values into a single such entry. 1995 1995 For example, 1996 1996 </p> 1997 1997 <div id="rfc.figure.u.69"></div><pre class="text"> Via: 1.0 ricky, 1.1 ethel, 1.1 fred, 1.0 lucy 1998 </pre><p id="rfc.section. 8.9.p.12">could be collapsed to</p>1998 </pre><p id="rfc.section.3.9.p.12">could be collapsed to</p> 1999 1999 <div id="rfc.figure.u.70"></div><pre class="text"> Via: 1.0 ricky, 1.1 mertz, 1.0 lucy 2000 </pre><p id="rfc.section. 8.9.p.14">Applications <em class="bcp14">SHOULD NOT</em> combine multiple entries unless they are all under the same organizational control and the hosts have already been replaced2000 </pre><p id="rfc.section.3.9.p.14">Applications <em class="bcp14">SHOULD NOT</em> combine multiple entries unless they are all under the same organizational control and the hosts have already been replaced 2001 2001 by pseudonyms. Applications <em class="bcp14">MUST NOT</em> combine entries which have different received-protocol values. 2002 2002 </p> 2003 <h1 id="rfc.section. 9"><a href="#rfc.section.9">9.</a> <a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1>2004 <h2 id="rfc.section. 9.1"><a href="#rfc.section.9.1">9.1</a> <a id="message.header.registration" href="#message.header.registration">Message Header Registration</a></h2>2005 <p id="rfc.section. 9.1.p.1">The Message Header Registry located at <<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>> should 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>):2003 <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a> <a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1> 2004 <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a> <a id="message.header.registration" href="#message.header.registration">Message Header Registration</a></h2> 2005 <p id="rfc.section.4.1.p.1">The Message Header Registry located at <<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>> should 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>): 2006 2006 </p> 2007 2007 <div id="rfc.table.1"> … … 2021 2021 <td>http</td> 2022 2022 <td>standard</td> 2023 <td> <a href="#header.connection" id="rfc.xref.header.connection.6" title="Connection">Section 8.1</a>2023 <td> <a href="#header.connection" id="rfc.xref.header.connection.6" title="Connection">Section 3.1</a> 2024 2024 </td> 2025 2025 </tr> … … 2028 2028 <td>http</td> 2029 2029 <td>standard</td> 2030 <td> <a href="#header.content-length" id="rfc.xref.header.content-length.2" title="Content-Length">Section 8.2</a>2030 <td> <a href="#header.content-length" id="rfc.xref.header.content-length.2" title="Content-Length">Section 3.2</a> 2031 2031 </td> 2032 2032 </tr> … … 2035 2035 <td>http</td> 2036 2036 <td>standard</td> 2037 <td> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section 8.3</a>2037 <td> <a href="#header.date" id="rfc.xref.header.date.2" title="Date">Section 3.3</a> 2038 2038 </td> 2039 2039 </tr> … … 2042 2042 <td>http</td> 2043 2043 <td>standard</td> 2044 <td> <a href="#header.host" id="rfc.xref.header.host.1" title="Host">Section 8.4</a>2044 <td> <a href="#header.host" id="rfc.xref.header.host.1" title="Host">Section 3.4</a> 2045 2045 </td> 2046 2046 </tr> … … 2049 2049 <td>http</td> 2050 2050 <td>standard</td> 2051 <td> <a href="#header.te" id="rfc.xref.header.te.4" title="TE">Section 8.5</a>2051 <td> <a href="#header.te" id="rfc.xref.header.te.4" title="TE">Section 3.5</a> 2052 2052 </td> 2053 2053 </tr> … … 2056 2056 <td>http</td> 2057 2057 <td>standard</td> 2058 <td> <a href="#header.trailer" id="rfc.xref.header.trailer.3" title="Trailer">Section 8.6</a>2058 <td> <a href="#header.trailer" id="rfc.xref.header.trailer.3" title="Trailer">Section 3.6</a> 2059 2059 </td> 2060 2060 </tr> … … 2063 2063 <td>http</td> 2064 2064 <td>standard</td> 2065 <td> <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.5" title="Transfer-Encoding">Section 8.7</a>2065 <td> <a href="#header.transfer-encoding" id="rfc.xref.header.transfer-encoding.5" title="Transfer-Encoding">Section 3.7</a> 2066 2066 </td> 2067 2067 </tr> … … 2070 2070 <td>http</td> 2071 2071 <td>standard</td> 2072 <td> <a href="#header.upgrade" id="rfc.xref.header.upgrade.2" title="Upgrade">Section 8.8</a>2072 <td> <a href="#header.upgrade" id="rfc.xref.header.upgrade.2" title="Upgrade">Section 3.8</a> 2073 2073 </td> 2074 2074 </tr> … … 2077 2077 <td>http</td> 2078 2078 <td>standard</td> 2079 <td> <a href="#header.via" id="rfc.xref.header.via.2" title="Via">Section 8.9</a>2079 <td> <a href="#header.via" id="rfc.xref.header.via.2" title="Via">Section 3.9</a> 2080 2080 </td> 2081 2081 </tr> … … 2083 2083 </table> 2084 2084 </div> 2085 <p id="rfc.section. 9.1.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p>2086 <h2 id="rfc.section. 9.2"><a href="#rfc.section.9.2">9.2</a> <a id="uri.scheme.registration" href="#uri.scheme.registration">URI Scheme Registration</a></h2>2087 <p id="rfc.section. 9.2.p.1">The entries for the "http" and "https" URI Schemes in the registry located at <<a href="http://www.iana.org/assignments/uri-schemes.html">http://www.iana.org/assignments/uri-schemes.html</a>> should be updated to point to Sections <a href="#http.uri" title="http URI scheme">2.6.1</a> and <a href="#https.uri" title="https URI scheme">2.6.2</a> of this document (see <a href="#RFC4395" id="rfc.xref.RFC4395.1"><cite title="Guidelines and Registration Procedures for New URI Schemes">[RFC4395]</cite></a>).2088 </p> 2089 <h2 id="rfc.section. 9.3"><a href="#rfc.section.9.3">9.3</a> <a id="internet.media.type.http" href="#internet.media.type.http">Internet Media Type Registrations</a></h2>2090 <p id="rfc.section. 9.3.p.1">This document serves as the specification for the Internet media types "message/http" and "application/http". The following2085 <p id="rfc.section.4.1.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p> 2086 <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a> <a id="uri.scheme.registration" href="#uri.scheme.registration">URI Scheme Registration</a></h2> 2087 <p id="rfc.section.4.2.p.1">The entries for the "http" and "https" URI Schemes in the registry located at <<a href="http://www.iana.org/assignments/uri-schemes.html">http://www.iana.org/assignments/uri-schemes.html</a>> should be updated to point to Sections <a href="#http.uri" title="http URI scheme">2.6.1</a> and <a href="#https.uri" title="https URI scheme">2.6.2</a> of this document (see <a href="#RFC4395" id="rfc.xref.RFC4395.1"><cite title="Guidelines and Registration Procedures for New URI Schemes">[RFC4395]</cite></a>). 2088 </p> 2089 <h2 id="rfc.section.4.3"><a href="#rfc.section.4.3">4.3</a> <a id="internet.media.type.http" href="#internet.media.type.http">Internet Media Type Registrations</a></h2> 2090 <p id="rfc.section.4.3.p.1">This document serves as the specification for the Internet media types "message/http" and "application/http". The following 2091 2091 is to be registered with IANA (see <a href="#RFC4288" id="rfc.xref.RFC4288.1"><cite title="Media Type Specifications and Registration Procedures">[RFC4288]</cite></a>). 2092 2092 </p> 2093 2093 <div id="rfc.iref.m.2"></div> 2094 2094 <div id="rfc.iref.m.3"></div> 2095 <h3 id="rfc.section. 9.3.1"><a href="#rfc.section.9.3.1">9.3.1</a> <a id="internet.media.type.message.http" href="#internet.media.type.message.http">Internet Media Type message/http</a></h3>2096 <p id="rfc.section. 9.3.1.p.1">The message/http type can be used to enclose a single HTTP request or response message, provided that it obeys the MIME restrictions2095 <h3 id="rfc.section.4.3.1"><a href="#rfc.section.4.3.1">4.3.1</a> <a id="internet.media.type.message.http" href="#internet.media.type.message.http">Internet Media Type message/http</a></h3> 2096 <p id="rfc.section.4.3.1.p.1">The message/http type can be used to enclose a single HTTP request or response message, provided that it obeys the MIME restrictions 2097 2097 for all "message" types regarding line length and encodings. 2098 2098 </p> 2099 <p id="rfc.section. 9.3.1.p.2"> </p>2099 <p id="rfc.section.4.3.1.p.2"> </p> 2100 2100 <dl> 2101 2101 <dt>Type name:</dt> … … 2123 2123 <dd>none</dd> 2124 2124 <dt>Published specification:</dt> 2125 <dd>This specification (see <a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section 9.3.1</a>).2125 <dd>This specification (see <a href="#internet.media.type.message.http" title="Internet Media Type message/http">Section 4.3.1</a>). 2126 2126 </dd> 2127 2127 <dt>Applications that use this media type:</dt> … … 2148 2148 <div id="rfc.iref.m.4"></div> 2149 2149 <div id="rfc.iref.a.1"></div> 2150 <h3 id="rfc.section. 9.3.2"><a href="#rfc.section.9.3.2">9.3.2</a> <a id="internet.media.type.application.http" href="#internet.media.type.application.http">Internet Media Type application/http</a></h3>2151 <p id="rfc.section. 9.3.2.p.1">The application/http type can be used to enclose a pipeline of one or more HTTP request or response messages (not intermixed).</p>2152 <p id="rfc.section. 9.3.2.p.2"> </p>2150 <h3 id="rfc.section.4.3.2"><a href="#rfc.section.4.3.2">4.3.2</a> <a id="internet.media.type.application.http" href="#internet.media.type.application.http">Internet Media Type application/http</a></h3> 2151 <p id="rfc.section.4.3.2.p.1">The application/http type can be used to enclose a pipeline of one or more HTTP request or response messages (not intermixed).</p> 2152 <p id="rfc.section.4.3.2.p.2"> </p> 2153 2153 <dl> 2154 2154 <dt>Type name:</dt> … … 2178 2178 <dd>none</dd> 2179 2179 <dt>Published specification:</dt> 2180 <dd>This specification (see <a href="#internet.media.type.application.http" title="Internet Media Type application/http">Section 9.3.2</a>).2180 <dd>This specification (see <a href="#internet.media.type.application.http" title="Internet Media Type application/http">Section 4.3.2</a>). 2181 2181 </dd> 2182 2182 <dt>Applications that use this media type:</dt> … … 2201 2201 <dd>IESG</dd> 2202 2202 </dl> 2203 <h1 id="rfc.section.10"><a href="#rfc.section.10">10.</a> <a id="security.considerations" href="#security.considerations">Security Considerations</a></h1> 2204 <p id="rfc.section.10.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1 2203 <h2 id="rfc.section.4.4"><a href="#rfc.section.4.4">4.4</a> <a id="transfer.coding.registration" href="#transfer.coding.registration">Transfer Coding Registry</a></h2> 2204 <p id="rfc.section.4.4.p.1">The registration procedure for HTTP Transfer Codings is now defined by <a href="#transfer.codings" title="Transfer Codings">Section 2.10.2</a> of this document. 2205 </p> 2206 <p id="rfc.section.4.4.p.2">The HTTP Transfer Codings Registry located at <<a href="http://www.iana.org/assignments/http-parameters">http://www.iana.org/assignments/http-parameters</a>> should be updated with the registration below: 2207 </p> 2208 <div id="rfc.table.2"> 2209 <div id="iana.transfer.coding.registration.table"></div> 2210 <table summary="" class="tt full" cellpadding="3" cellspacing="0"> 2211 <thead> 2212 <tr> 2213 <th>Registry Name</th> 2214 <th>Description</th> 2215 <th>Reference</th> 2216 </tr> 2217 </thead> 2218 <tbody> 2219 <tr> 2220 <td>Chunked</td> 2221 <td>Transfer in a series of chunks</td> 2222 <td> <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 2.10.2.1</a> 2223 </td> 2224 </tr> 2225 </tbody> 2226 </table> 2227 </div> 2228 <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a> <a id="security.considerations" href="#security.considerations">Security Considerations</a></h1> 2229 <p id="rfc.section.5.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1 2205 2230 as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does 2206 2231 make some suggestions for reducing security risks. 2207 2232 </p> 2208 <h2 id="rfc.section. 10.1"><a href="#rfc.section.10.1">10.1</a> <a id="personal.information" href="#personal.information">Personal Information</a></h2>2209 <p id="rfc.section. 10.1.p.1">HTTP clients are often privy to large amounts of personal information (e.g. the user's name, location, mail address, passwords,2233 <h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a> <a id="personal.information" href="#personal.information">Personal Information</a></h2> 2234 <p id="rfc.section.5.1.p.1">HTTP clients are often privy to large amounts of personal information (e.g. the user's name, location, mail address, passwords, 2210 2235 encryption keys, etc.), and <em class="bcp14">SHOULD</em> be very careful to prevent unintentional leakage of this information. We very strongly recommend that a convenient interface 2211 2236 be provided for the user to control dissemination of such information, and that designers and implementors be particularly … … 2213 2238 highly adverse publicity for the implementor's company. 2214 2239 </p> 2215 <h2 id="rfc.section. 10.2"><a href="#rfc.section.10.2">10.2</a> <a id="abuse.of.server.log.information" href="#abuse.of.server.log.information">Abuse of Server Log Information</a></h2>2216 <p id="rfc.section. 10.2.p.1">A server is in the position to save personal data about a user's requests which might identify their reading patterns or subjects2240 <h2 id="rfc.section.5.2"><a href="#rfc.section.5.2">5.2</a> <a id="abuse.of.server.log.information" href="#abuse.of.server.log.information">Abuse of Server Log Information</a></h2> 2241 <p id="rfc.section.5.2.p.1">A server is in the position to save personal data about a user's requests which might identify their reading patterns or subjects 2217 2242 of interest. This information is clearly confidential in nature and its handling can be constrained by law in certain countries. 2218 2243 People using HTTP to provide data are responsible for ensuring that such material is not distributed without the permission 2219 2244 of any individuals that are identifiable by the published results. 2220 2245 </p> 2221 <h2 id="rfc.section. 10.3"><a href="#rfc.section.10.3">10.3</a> <a id="attack.pathname" href="#attack.pathname">Attacks Based On File and Path Names</a></h2>2222 <p id="rfc.section. 10.3.p.1">Implementations of HTTP origin servers <em class="bcp14">SHOULD</em> be careful to restrict the documents returned by HTTP requests to be only those that were intended by the server administrators.2246 <h2 id="rfc.section.5.3"><a href="#rfc.section.5.3">5.3</a> <a id="attack.pathname" href="#attack.pathname">Attacks Based On File and Path Names</a></h2> 2247 <p id="rfc.section.5.3.p.1">Implementations of HTTP origin servers <em class="bcp14">SHOULD</em> be careful to restrict the documents returned by HTTP requests to be only those that were intended by the server administrators. 2223 2248 If an HTTP server translates HTTP URIs directly into file system calls, the server <em class="bcp14">MUST</em> take special care not to serve files that were not intended to be delivered to HTTP clients. For example, UNIX, Microsoft 2224 2249 Windows, and other operating systems use ".." as a path component to indicate a directory level above the current one. On … … 2228 2253 bugs in such HTTP server implementations have turned into security risks. 2229 2254 </p> 2230 <h2 id="rfc.section. 10.4"><a href="#rfc.section.10.4">10.4</a> <a id="dns.spoofing" href="#dns.spoofing">DNS Spoofing</a></h2>2231 <p id="rfc.section. 10.4.p.1">Clients using HTTP rely heavily on the Domain Name Service, and are thus generally prone to security attacks based on the2255 <h2 id="rfc.section.5.4"><a href="#rfc.section.5.4">5.4</a> <a id="dns.spoofing" href="#dns.spoofing">DNS Spoofing</a></h2> 2256 <p id="rfc.section.5.4.p.1">Clients using HTTP rely heavily on the Domain Name Service, and are thus generally prone to security attacks based on the 2232 2257 deliberate mis-association of IP addresses and DNS names. Clients need to be cautious in assuming the continuing validity 2233 2258 of an IP number/DNS name association. 2234 2259 </p> 2235 <p id="rfc.section. 10.4.p.2">In particular, HTTP clients <em class="bcp14">SHOULD</em> rely on their name resolver for confirmation of an IP number/DNS name association, rather than caching the result of previous2260 <p id="rfc.section.5.4.p.2">In particular, HTTP clients <em class="bcp14">SHOULD</em> rely on their name resolver for confirmation of an IP number/DNS name association, rather than caching the result of previous 2236 2261 host name lookups. Many platforms already can cache host name lookups locally when appropriate, and they <em class="bcp14">SHOULD</em> be configured to do so. It is proper for these lookups to be cached, however, only when the TTL (Time To Live) information 2237 2262 reported by the name server makes it likely that the cached information will remain useful. 2238 2263 </p> 2239 <p id="rfc.section. 10.4.p.3">If HTTP clients cache the results of host name lookups in order to achieve a performance improvement, they <em class="bcp14">MUST</em> observe the TTL information reported by DNS.2240 </p> 2241 <p id="rfc.section. 10.4.p.4">If HTTP clients do not observe this rule, they could be spoofed when a previously-accessed server's IP address changes. As2264 <p id="rfc.section.5.4.p.3">If HTTP clients cache the results of host name lookups in order to achieve a performance improvement, they <em class="bcp14">MUST</em> observe the TTL information reported by DNS. 2265 </p> 2266 <p id="rfc.section.5.4.p.4">If HTTP clients do not observe this rule, they could be spoofed when a previously-accessed server's IP address changes. As 2242 2267 network renumbering is expected to become increasingly common <a href="#RFC1900" id="rfc.xref.RFC1900.1"><cite title="Renumbering Needs Work">[RFC1900]</cite></a>, the possibility of this form of attack will grow. Observing this requirement thus reduces this potential security vulnerability. 2243 2268 </p> 2244 <p id="rfc.section. 10.4.p.5">This requirement also improves the load-balancing behavior of clients for replicated servers using the same DNS name and reduces2269 <p id="rfc.section.5.4.p.5">This requirement also improves the load-balancing behavior of clients for replicated servers using the same DNS name and reduces 2245 2270 the likelihood of a user's experiencing failure in accessing sites which use that strategy. 2246 2271 </p> 2247 <h2 id="rfc.section. 10.5"><a href="#rfc.section.10.5">10.5</a> <a id="attack.proxies" href="#attack.proxies">Proxies and Caching</a></h2>2248 <p id="rfc.section. 10.5.p.1">By their very nature, HTTP proxies are men-in-the-middle, and represent an opportunity for man-in-the-middle attacks. Compromise2272 <h2 id="rfc.section.5.5"><a href="#rfc.section.5.5">5.5</a> <a id="attack.proxies" href="#attack.proxies">Proxies and Caching</a></h2> 2273 <p id="rfc.section.5.5.p.1">By their very nature, HTTP proxies are men-in-the-middle, and represent an opportunity for man-in-the-middle attacks. Compromise 2249 2274 of the systems on which the proxies run can result in serious security and privacy problems. Proxies have access to security-related 2250 2275 information, personal information about individual users and organizations, and proprietary information belonging to users … … 2252 2277 might be used in the commission of a wide range of potential attacks. 2253 2278 </p> 2254 <p id="rfc.section. 10.5.p.2">Proxy operators should protect the systems on which proxies run as they would protect any system that contains or transports2279 <p id="rfc.section.5.5.p.2">Proxy operators should protect the systems on which proxies run as they would protect any system that contains or transports 2255 2280 sensitive information. In particular, log information gathered at proxies often contains highly sensitive personal information, 2256 2281 and/or information about organizations. Log information should be carefully guarded, and appropriate guidelines for use developed 2257 and followed. (<a href="#abuse.of.server.log.information" title="Abuse of Server Log Information">Section 10.2</a>).2258 </p> 2259 <p id="rfc.section. 10.5.p.3">Proxy implementors should consider the privacy and security implications of their design and coding decisions, and of the2282 and followed. (<a href="#abuse.of.server.log.information" title="Abuse of Server Log Information">Section 5.2</a>). 2283 </p> 2284 <p id="rfc.section.5.5.p.3">Proxy implementors should consider the privacy and security implications of their design and coding decisions, and of the 2260 2285 configuration options they provide to proxy operators (especially the default configuration). 2261 2286 </p> 2262 <p id="rfc.section. 10.5.p.4">Users of a proxy need to be aware that they are no trustworthier than the people who run the proxy; HTTP itself cannot solve2287 <p id="rfc.section.5.5.p.4">Users of a proxy need to be aware that they are no trustworthier than the people who run the proxy; HTTP itself cannot solve 2263 2288 this problem. 2264 2289 </p> 2265 <p id="rfc.section. 10.5.p.5">The judicious use of cryptography, when appropriate, may suffice to protect against a broad range of security and privacy2290 <p id="rfc.section.5.5.p.5">The judicious use of cryptography, when appropriate, may suffice to protect against a broad range of security and privacy 2266 2291 attacks. Such cryptography is beyond the scope of the HTTP/1.1 specification. 2267 2292 </p> 2268 <h2 id="rfc.section. 10.6"><a href="#rfc.section.10.6">10.6</a> <a id="attack.DoS" href="#attack.DoS">Denial of Service Attacks on Proxies</a></h2>2269 <p id="rfc.section. 10.6.p.1">They exist. They are hard to defend against. Research continues. Beware.</p>2270 <h1 id="rfc.section. 11"><a href="#rfc.section.11">11.</a> <a id="ack" href="#ack">Acknowledgments</a></h1>2271 <p id="rfc.section. 11.p.1">HTTP has evolved considerably over the years. It has benefited from a large and active developer community--the many people2293 <h2 id="rfc.section.5.6"><a href="#rfc.section.5.6">5.6</a> <a id="attack.DoS" href="#attack.DoS">Denial of Service Attacks on Proxies</a></h2> 2294 <p id="rfc.section.5.6.p.1">They exist. They are hard to defend against. Research continues. Beware.</p> 2295 <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a> <a id="ack" href="#ack">Acknowledgments</a></h1> 2296 <p id="rfc.section.6.p.1">HTTP has evolved considerably over the years. It has benefited from a large and active developer community--the many people 2272 2297 who have participated on the www-talk mailing list--and it is that community which has been most responsible for the success 2273 2298 of HTTP and of the World-Wide Web in general. Marc Andreessen, Robert Cailliau, Daniel W. Connolly, Bob Denny, John Franks, … … 2275 2300 and Marc VanHeyningen deserve special recognition for their efforts in defining early aspects of the protocol. 2276 2301 </p> 2277 <p id="rfc.section. 11.p.2">This document has benefited greatly from the comments of all those participating in the HTTP-WG. In addition to those already2302 <p id="rfc.section.6.p.2">This document has benefited greatly from the comments of all those participating in the HTTP-WG. In addition to those already 2278 2303 mentioned, the following individuals have contributed to this specification: 2279 2304 </p> 2280 <p id="rfc.section. 11.p.3">Gary Adams, Harald Tveit Alvestrand, Keith Ball, Brian Behlendorf, Paul Burchard, Maurizio Codogno, Mike Cowlishaw, Roman2305 <p id="rfc.section.6.p.3">Gary Adams, Harald Tveit Alvestrand, Keith Ball, Brian Behlendorf, Paul Burchard, Maurizio Codogno, Mike Cowlishaw, Roman 2281 2306 Czyborra, Michael A. Dolan, Daniel DuBois, David J. Fiander, Alan Freier, Marc Hedlund, Greg Herlihy, Koen Holtman, Alex Hopmann, 2282 2307 Bob Jernigan, Shel Kaphan, Rohit Khare, John Klensin, Martijn Koster, Alexei Kosut, David M. Kristol, Daniel LaLiberte, Ben … … 2286 2311 Weinman, Francois Yergeau, Mary Ellen Zurko, Josh Cohen. 2287 2312 </p> 2288 <p id="rfc.section. 11.p.4">Thanks to the "cave men" of Palo Alto. You know who you are.</p>2289 <p id="rfc.section. 11.p.5">Jim Gettys (the editor of <a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>) wishes particularly to thank Roy Fielding, the editor of <a href="#RFC2068" id="rfc.xref.RFC2068.4"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, along with John Klensin, Jeff Mogul, Paul Leach, Dave Kristol, Koen Holtman, John Franks, Josh Cohen, Alex Hopmann, Scott2313 <p id="rfc.section.6.p.4">Thanks to the "cave men" of Palo Alto. You know who you are.</p> 2314 <p id="rfc.section.6.p.5">Jim Gettys (the editor of <a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>) wishes particularly to thank Roy Fielding, the editor of <a href="#RFC2068" id="rfc.xref.RFC2068.4"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>, along with John Klensin, Jeff Mogul, Paul Leach, Dave Kristol, Koen Holtman, John Franks, Josh Cohen, Alex Hopmann, Scott 2290 2315 Lawrence, and Larry Masinter for their help. And thanks go particularly to Jeff Mogul and Scott Lawrence for performing the 2291 2316 "MUST/MAY/SHOULD" audit. 2292 2317 </p> 2293 <p id="rfc.section. 11.p.6">The Apache Group, Anselm Baird-Smith, author of Jigsaw, and Henrik Frystyk implemented RFC 2068 early, and we wish to thank2318 <p id="rfc.section.6.p.6">The Apache Group, Anselm Baird-Smith, author of Jigsaw, and Henrik Frystyk implemented RFC 2068 early, and we wish to thank 2294 2319 them for the discovery of many of the problems that this document attempts to rectify. 2295 2320 </p> 2296 <p id="rfc.section. 11.p.7">This specification makes heavy use of the augmented BNF and generic constructs defined by David H. Crocker for <a href="#RFC5234" id="rfc.xref.RFC5234.4"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. Similarly, it reuses many of the definitions provided by Nathaniel Borenstein and Ned Freed for MIME <a href="#RFC2045" id="rfc.xref.RFC2045.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>. We hope that their inclusion in this specification will help reduce past confusion over the relationship between HTTP and2321 <p id="rfc.section.6.p.7">This specification makes heavy use of the augmented BNF and generic constructs defined by David H. Crocker for <a href="#RFC5234" id="rfc.xref.RFC5234.4"><cite title="Augmented BNF for Syntax Specifications: ABNF">[RFC5234]</cite></a>. Similarly, it reuses many of the definitions provided by Nathaniel Borenstein and Ned Freed for MIME <a href="#RFC2045" id="rfc.xref.RFC2045.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>. We hope that their inclusion in this specification will help reduce past confusion over the relationship between HTTP and 2297 2322 Internet mail message formats. 2298 2323 </p> 2299 <h1 id="rfc.references"><a id="rfc.section. 12" href="#rfc.section.12">12.</a> References2324 <h1 id="rfc.references"><a id="rfc.section.7" href="#rfc.section.7">7.</a> References 2300 2325 </h1> 2301 <h2 id="rfc.references.1"><a href="#rfc.section. 12.1" id="rfc.section.12.1">12.1</a> Normative References2326 <h2 id="rfc.references.1"><a href="#rfc.section.7.1" id="rfc.section.7.1">7.1</a> Normative References 2302 2327 </h2> 2303 2328 <table summary="Normative References"> … … 2346 2371 </tr> 2347 2372 </table> 2348 <h2 id="rfc.references.2"><a href="#rfc.section. 12.2" id="rfc.section.12.2">12.2</a> Informative References2373 <h2 id="rfc.references.2"><a href="#rfc.section.7.2" id="rfc.section.7.2">7.2</a> Informative References 2349 2374 </h2> 2350 2375 <table summary="Informative References"> … … 2532 2557 <p id="rfc.section.B.1.p.1">This section summarizes major differences between versions HTTP/1.0 and HTTP/1.1.</p> 2533 2558 <h3 id="rfc.section.B.1.1"><a href="#rfc.section.B.1.1">B.1.1</a> <a id="changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses" href="#changes.to.simplify.multi-homed.web.servers.and.conserve.ip.addresses">Changes to Simplify Multi-homed Web Servers and Conserve IP Addresses</a></h3> 2534 <p id="rfc.section.B.1.1.p.1">The requirements that clients and servers support the Host request-header, report an error if the Host request-header (<a href="#header.host" id="rfc.xref.header.host.2" title="Host">Section 8.4</a>) is missing from an HTTP/1.1 request, and accept absolute URIs (<a href="#request-target" title="request-target">Section 4.1.2</a>) are among the most important changes defined by this specification.2559 <p id="rfc.section.B.1.1.p.1">The requirements that clients and servers support the Host request-header, report an error if the Host request-header (<a href="#header.host" id="rfc.xref.header.host.2" title="Host">Section 3.4</a>) is missing from an HTTP/1.1 request, and accept absolute URIs (<a href="#request-target" title="request-target">Section 2.8.1.2</a>) are among the most important changes defined by this specification. 2535 2560 </p> 2536 2561 <p id="rfc.section.B.1.1.p.2">Older HTTP/1.0 clients assumed a one-to-one relationship of IP addresses and servers; there was no other established mechanism … … 2565 2590 Therefore, we need some other mechanism for indicating a persistent connection is desired, which is safe to use even when 2566 2591 talking to an old proxy that ignores Connection. Persistent connections are the default for HTTP/1.1 messages; we introduce 2567 a new keyword (Connection: close) for declaring non-persistence. See <a href="#header.connection" id="rfc.xref.header.connection.7" title="Connection">Section 8.1</a>.2592 a new keyword (Connection: close) for declaring non-persistence. See <a href="#header.connection" id="rfc.xref.header.connection.7" title="Connection">Section 3.1</a>. 2568 2593 </p> 2569 2594 <p id="rfc.section.B.2.p.3">The original HTTP/1.0 form of persistent connections (the Connection: Keep-Alive and Keep-Alive header) is documented in <a href="http://tools.ietf.org/html/rfc2068#section-19.7.1">Section 19.7.1</a> of <a href="#RFC2068" id="rfc.xref.RFC2068.6"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>. … … 2575 2600 <p id="rfc.section.B.3.p.2">Transfer-coding and message lengths all interact in ways that required fixing exactly when chunked encoding is used (to allow 2576 2601 for transfer encoding that may not be self delimiting); it was important to straighten out exactly how message lengths are 2577 computed. (Sections <a href="#transfer.codings" title="Transfer Codings"> 6.2</a>, <a href="#message.length" title="Message Length">3.4</a>, <a href="#header.content-length" id="rfc.xref.header.content-length.3" title="Content-Length">8.2</a>, see also <a href="#Part3" id="rfc.xref.Part3.11"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="#Part5" id="rfc.xref.Part5.1"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a> and <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>)2602 computed. (Sections <a href="#transfer.codings" title="Transfer Codings">2.10.2</a>, <a href="#message.length" title="Message Length">2.7.4</a>, <a href="#header.content-length" id="rfc.xref.header.content-length.3" title="Content-Length">3.2</a>, see also <a href="#Part3" id="rfc.xref.Part3.11"><cite title="HTTP/1.1, part 3: Message Payload and Content Negotiation">[Part3]</cite></a>, <a href="#Part5" id="rfc.xref.Part5.1"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a> and <a href="#Part6" id="rfc.xref.Part6.8"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) 2578 2603 </p> 2579 2604 <p id="rfc.section.B.3.p.3">The use and interpretation of HTTP version numbers has been clarified by <a href="#RFC2145" id="rfc.xref.RFC2145.3"><cite title="Use and Interpretation of HTTP Version Numbers">[RFC2145]</cite></a>. Require proxies to upgrade requests to highest protocol version they support to deal with problems discovered in HTTP/1.0 2580 2605 implementations (<a href="#http.version" title="HTTP Version">Section 2.5</a>) 2581 2606 </p> 2582 <p id="rfc.section.B.3.p.4">Quality Values of zero should indicate that "I don't want something" to allow clients to refuse a representation. (<a href="#quality.values" title="Quality Values">Section 6.4</a>)2607 <p id="rfc.section.B.3.p.4">Quality Values of zero should indicate that "I don't want something" to allow clients to refuse a representation. (<a href="#quality.values" title="Quality Values">Section 2.10.4</a>) 2583 2608 </p> 2584 2609 <p id="rfc.section.B.3.p.5">Transfer-coding had significant problems, particularly with interactions with chunked encoding. The solution is that transfer-codings … … 2586 2611 codings), a new header field (TE) and enabling trailer headers in the future. Transfer encoding is a major performance benefit, 2587 2612 so it was worth fixing <a href="#Nie1997" id="rfc.xref.Nie1997.2"><cite title="Network Performance Effects of HTTP/1.1, CSS1, and PNG">[Nie1997]</cite></a>. TE also solves another, obscure, downward interoperability problem that could have occurred due to interactions between 2588 authentication trailers, chunked encoding and HTTP/1.0 clients.(Section <a href="#transfer.codings" title="Transfer Codings"> 6.2</a>, <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">6.2.1</a>, and <a href="#header.te" id="rfc.xref.header.te.5" title="TE">8.5</a>)2613 authentication trailers, chunked encoding and HTTP/1.0 clients.(Section <a href="#transfer.codings" title="Transfer Codings">2.10.2</a>, <a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">2.10.2.1</a>, and <a href="#header.te" id="rfc.xref.header.te.5" title="TE">3.5</a>) 2589 2614 </p> 2590 2615 <h2 id="rfc.section.B.4"><a href="#rfc.section.B.4">B.4</a> <a id="changes.from.rfc.2616" href="#changes.from.rfc.2616">Changes from RFC 2616</a></h2> … … 2598 2623 <p id="rfc.section.B.4.p.3">Clarify that HTTP-Version is case sensitive. (<a href="#http.version" title="HTTP Version">Section 2.5</a>) 2599 2624 </p> 2600 <p id="rfc.section.B.4.p.4">Remove reference to non-existant identity transfer-coding value tokens. (Sections <a href="#transfer.codings" title="Transfer Codings"> 6.2</a> and <a href="#message.length" title="Message Length">3.4</a>)2601 </p> 2602 <p id="rfc.section.B.4.p.5">Clarification that the chunk length does not include the count of the octets in the chunk header and trailer. (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 6.2.1</a>)2603 </p> 2604 <p id="rfc.section.B.4.p.6">Require that invalid whitespace around field-names be rejected. (<a href="#header.fields" title="Header Fields">Section 3.2</a>)2605 </p> 2606 <p id="rfc.section.B.4.p.7">Update use of abs_path production from RFC1808 to the path-absolute + query components of RFC3986. (<a href="#request-target" title="request-target">Section 4.1.2</a>)2607 </p> 2608 <p id="rfc.section.B.4.p.8">Clarify exactly when close connection options must be sent. (<a href="#header.connection" id="rfc.xref.header.connection.8" title="Connection">Section 8.1</a>)2625 <p id="rfc.section.B.4.p.4">Remove reference to non-existant identity transfer-coding value tokens. (Sections <a href="#transfer.codings" title="Transfer Codings">2.10.2</a> and <a href="#message.length" title="Message Length">2.7.4</a>) 2626 </p> 2627 <p id="rfc.section.B.4.p.5">Clarification that the chunk length does not include the count of the octets in the chunk header and trailer. (<a href="#chunked.transfer.encoding" title="Chunked Transfer Coding">Section 2.10.2.1</a>) 2628 </p> 2629 <p id="rfc.section.B.4.p.6">Require that invalid whitespace around field-names be rejected. (<a href="#header.fields" title="Header Fields">Section 2.7.2</a>) 2630 </p> 2631 <p id="rfc.section.B.4.p.7">Update use of abs_path production from RFC1808 to the path-absolute + query components of RFC3986. (<a href="#request-target" title="request-target">Section 2.8.1.2</a>) 2632 </p> 2633 <p id="rfc.section.B.4.p.8">Clarify exactly when close connection options must be sent. (<a href="#header.connection" id="rfc.xref.header.connection.8" title="Connection">Section 3.1</a>) 2609 2634 </p> 2610 2635 <h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a> <a id="terminology" href="#terminology">Terminology</a></h1> … … 3030 3055 </li> 3031 3056 </ul> 3057 <p id="rfc.section.E.9.p.2">Partly resolved issues: </p> 3058 <ul> 3059 <li> <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/148">http://tools.ietf.org/wg/httpbis/trac/ticket/148</a>>: "update IANA requirements wrt Transfer-Coding values" (add the IANA Considerations subsection) 3060 </li> 3061 </ul> 3032 3062 <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1> 3033 3063 <p class="noprint"><a href="#rfc.index.A">A</a> <a href="#rfc.index.C">C</a> <a href="#rfc.index.D">D</a> <a href="#rfc.index.E">E</a> <a href="#rfc.index.G">G</a> <a href="#rfc.index.H">H</a> <a href="#rfc.index.I">I</a> <a href="#rfc.index.K">K</a> <a href="#rfc.index.M">M</a> <a href="#rfc.index.N">N</a> <a href="#rfc.index.O">O</a> <a href="#rfc.index.P">P</a> <a href="#rfc.index.R">R</a> <a href="#rfc.index.S">S</a> <a href="#rfc.index.T">T</a> <a href="#rfc.index.U">U</a> <a href="#rfc.index.V">V</a> … … 3036 3066 <ul class="ind"> 3037 3067 <li class="indline0"><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul class="ind"> 3038 <li class="indline1">application/http Media Type <a class="iref" href="#rfc.iref.a.1"><b> 9.3.2</b></a></li>3068 <li class="indline1">application/http Media Type <a class="iref" href="#rfc.iref.a.1"><b>4.3.2</b></a></li> 3039 3069 </ul> 3040 3070 </li> … … 3044 3074 <li class="indline1">client <a class="iref" href="#rfc.iref.c.1">2.1</a></li> 3045 3075 <li class="indline1">connection <a class="iref" href="#rfc.iref.c.2">2.1</a></li> 3046 <li class="indline1">Connection header <a class="iref" href="#rfc.xref.header.connection.1"> 3.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">7.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">7.1.3</a>, <a class="iref" href="#rfc.iref.c.5"><b>8.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">8.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">8.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">9.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li>3076 <li class="indline1">Connection header <a class="iref" href="#rfc.xref.header.connection.1">2.7.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">2.11.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">2.11.1.3</a>, <a class="iref" href="#rfc.iref.c.5"><b>3.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">3.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">3.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">4.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li> 3047 3077 <li class="indline1">content negotiation <a class="iref" href="#rfc.iref.c.7">C</a></li> 3048 <li class="indline1">Content-Length header <a class="iref" href="#rfc.xref.header.content-length.1"> 3.4</a>, <a class="iref" href="#rfc.iref.c.6"><b>8.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">9.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li>3078 <li class="indline1">Content-Length header <a class="iref" href="#rfc.xref.header.content-length.1">2.7.4</a>, <a class="iref" href="#rfc.iref.c.6"><b>3.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">4.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li> 3049 3079 </ul> 3050 3080 </li> 3051 3081 <li class="indline0"><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul class="ind"> 3052 <li class="indline1">Date header <a class="iref" href="#rfc.xref.header.date.1"> 3.5</a>, <a class="iref" href="#rfc.iref.d.2"><b>8.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">9.1</a></li>3082 <li class="indline1">Date header <a class="iref" href="#rfc.xref.header.date.1">2.7.5</a>, <a class="iref" href="#rfc.iref.d.2"><b>3.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">4.1</a></li> 3053 3083 <li class="indline1">downstream <a class="iref" href="#rfc.iref.d.1">2.2</a></li> 3054 3084 </ul> … … 3064 3094 <li class="indline1"><tt>absolute-URI</tt> <a class="iref" href="#rfc.iref.g.27"><b>2.6</b></a></li> 3065 3095 <li class="indline1">ALPHA <a class="iref" href="#rfc.iref.g.1"><b>1.2</b></a></li> 3066 <li class="indline1"><tt>asctime-date</tt> <a class="iref" href="#rfc.iref.g.69"><b> 6.1</b></a></li>3067 <li class="indline1"><tt>attribute</tt> <a class="iref" href="#rfc.iref.g.73"><b> 6.2</b></a></li>3096 <li class="indline1"><tt>asctime-date</tt> <a class="iref" href="#rfc.iref.g.69"><b>2.10.1</b></a></li> 3097 <li class="indline1"><tt>attribute</tt> <a class="iref" href="#rfc.iref.g.73"><b>2.10.2</b></a></li> 3068 3098 <li class="indline1"><tt>authority</tt> <a class="iref" href="#rfc.iref.g.28"><b>2.6</b></a></li> 3069 3099 <li class="indline1"><tt>BWS</tt> <a class="iref" href="#rfc.iref.g.15"><b>1.2.2</b></a></li> 3070 <li class="indline1"><tt>chunk</tt> <a class="iref" href="#rfc.iref.g.78"><b> 6.2.1</b></a></li>3071 <li class="indline1"><tt>chunk-data</tt> <a class="iref" href="#rfc.iref.g.84"><b> 6.2.1</b></a></li>3072 <li class="indline1"><tt>chunk-ext</tt> <a class="iref" href="#rfc.iref.g.81"><b> 6.2.1</b></a></li>3073 <li class="indline1"><tt>chunk-ext-name</tt> <a class="iref" href="#rfc.iref.g.82"><b> 6.2.1</b></a></li>3074 <li class="indline1"><tt>chunk-ext-val</tt> <a class="iref" href="#rfc.iref.g.83"><b> 6.2.1</b></a></li>3075 <li class="indline1"><tt>chunk-size</tt> <a class="iref" href="#rfc.iref.g.79"><b> 6.2.1</b></a></li>3076 <li class="indline1"><tt>Chunked-Body</tt> <a class="iref" href="#rfc.iref.g.77"><b> 6.2.1</b></a></li>3077 <li class="indline1"><tt>comment</tt> <a class="iref" href="#rfc.iref.g.40"><b> 3.2</b></a></li>3078 <li class="indline1"><tt>Connection</tt> <a class="iref" href="#rfc.iref.g.89"><b> 8.1</b></a></li>3079 <li class="indline1"><tt>connection-token</tt> <a class="iref" href="#rfc.iref.g.91"><b> 8.1</b></a></li>3080 <li class="indline1"><tt>Connection-v</tt> <a class="iref" href="#rfc.iref.g.90"><b> 8.1</b></a></li>3081 <li class="indline1"><tt>Content-Length</tt> <a class="iref" href="#rfc.iref.g.92"><b> 8.2</b></a></li>3082 <li class="indline1"><tt>Content-Length-v</tt> <a class="iref" href="#rfc.iref.g.93"><b> 8.2</b></a></li>3100 <li class="indline1"><tt>chunk</tt> <a class="iref" href="#rfc.iref.g.78"><b>2.10.2.1</b></a></li> 3101 <li class="indline1"><tt>chunk-data</tt> <a class="iref" href="#rfc.iref.g.84"><b>2.10.2.1</b></a></li> 3102 <li class="indline1"><tt>chunk-ext</tt> <a class="iref" href="#rfc.iref.g.81"><b>2.10.2.1</b></a></li> 3103 <li class="indline1"><tt>chunk-ext-name</tt> <a class="iref" href="#rfc.iref.g.82"><b>2.10.2.1</b></a></li> 3104 <li class="indline1"><tt>chunk-ext-val</tt> <a class="iref" href="#rfc.iref.g.83"><b>2.10.2.1</b></a></li> 3105 <li class="indline1"><tt>chunk-size</tt> <a class="iref" href="#rfc.iref.g.79"><b>2.10.2.1</b></a></li> 3106 <li class="indline1"><tt>Chunked-Body</tt> <a class="iref" href="#rfc.iref.g.77"><b>2.10.2.1</b></a></li> 3107 <li class="indline1"><tt>comment</tt> <a class="iref" href="#rfc.iref.g.40"><b>2.7.2</b></a></li> 3108 <li class="indline1"><tt>Connection</tt> <a class="iref" href="#rfc.iref.g.89"><b>3.1</b></a></li> 3109 <li class="indline1"><tt>connection-token</tt> <a class="iref" href="#rfc.iref.g.91"><b>3.1</b></a></li> 3110 <li class="indline1"><tt>Connection-v</tt> <a class="iref" href="#rfc.iref.g.90"><b>3.1</b></a></li> 3111 <li class="indline1"><tt>Content-Length</tt> <a class="iref" href="#rfc.iref.g.92"><b>3.2</b></a></li> 3112 <li class="indline1"><tt>Content-Length-v</tt> <a class="iref" href="#rfc.iref.g.93"><b>3.2</b></a></li> 3083 3113 <li class="indline1">CR <a class="iref" href="#rfc.iref.g.2"><b>1.2</b></a></li> 3084 3114 <li class="indline1">CRLF <a class="iref" href="#rfc.iref.g.3"><b>1.2</b></a></li> 3085 <li class="indline1"><tt>ctext</tt> <a class="iref" href="#rfc.iref.g.41"><b> 3.2</b></a></li>3115 <li class="indline1"><tt>ctext</tt> <a class="iref" href="#rfc.iref.g.41"><b>2.7.2</b></a></li> 3086 3116 <li class="indline1">CTL <a class="iref" href="#rfc.iref.g.4"><b>1.2</b></a></li> 3087 <li class="indline1"><tt>Date</tt> <a class="iref" href="#rfc.iref.g.94"><b> 8.3</b></a></li>3088 <li class="indline1"><tt>Date-v</tt> <a class="iref" href="#rfc.iref.g.95"><b> 8.3</b></a></li>3089 <li class="indline1"><tt>date1</tt> <a class="iref" href="#rfc.iref.g.56"><b> 6.1</b></a></li>3090 <li class="indline1"><tt>date2</tt> <a class="iref" href="#rfc.iref.g.75"><b> 6.2</b></a></li>3091 <li class="indline1"><tt>date3</tt> <a class="iref" href="#rfc.iref.g.76"><b> 6.2</b></a></li>3092 <li class="indline1"><tt>day</tt> <a class="iref" href="#rfc.iref.g.63"><b> 6.1</b></a></li>3093 <li class="indline1"><tt>day-name</tt> <a class="iref" href="#rfc.iref.g.61"><b> 6.1</b></a></li>3094 <li class="indline1"><tt>day-name-l</tt> <a class="iref" href="#rfc.iref.g.62"><b> 6.1</b></a></li>3117 <li class="indline1"><tt>Date</tt> <a class="iref" href="#rfc.iref.g.94"><b>3.3</b></a></li> 3118 <li class="indline1"><tt>Date-v</tt> <a class="iref" href="#rfc.iref.g.95"><b>3.3</b></a></li> 3119 <li class="indline1"><tt>date1</tt> <a class="iref" href="#rfc.iref.g.56"><b>2.10.1</b></a></li> 3120 <li class="indline1"><tt>date2</tt> <a class="iref" href="#rfc.iref.g.75"><b>2.10.2</b></a></li> 3121 <li class="indline1"><tt>date3</tt> <a class="iref" href="#rfc.iref.g.76"><b>2.10.2</b></a></li> 3122 <li class="indline1"><tt>day</tt> <a class="iref" href="#rfc.iref.g.63"><b>2.10.1</b></a></li> 3123 <li class="indline1"><tt>day-name</tt> <a class="iref" href="#rfc.iref.g.61"><b>2.10.1</b></a></li> 3124 <li class="indline1"><tt>day-name-l</tt> <a class="iref" href="#rfc.iref.g.62"><b>2.10.1</b></a></li> 3095 3125 <li class="indline1">DIGIT <a class="iref" href="#rfc.iref.g.5"><b>1.2</b></a></li> 3096 3126 <li class="indline1">DQUOTE <a class="iref" href="#rfc.iref.g.6"><b>1.2</b></a></li> 3097 <li class="indline1"><tt>extension-code</tt> <a class="iref" href="#rfc.iref.g.52"><b> 5.1.1</b></a></li>3098 <li class="indline1"><tt>extension-method</tt> <a class="iref" href="#rfc.iref.g.47"><b> 4.1.1</b></a></li>3099 <li class="indline1"><tt>field-content</tt> <a class="iref" href="#rfc.iref.g.39"><b> 3.2</b></a></li>3100 <li class="indline1"><tt>field-name</tt> <a class="iref" href="#rfc.iref.g.37"><b> 3.2</b></a></li>3101 <li class="indline1"><tt>field-value</tt> <a class="iref" href="#rfc.iref.g.38"><b> 3.2</b></a></li>3102 <li class="indline1"><tt>general-header</tt> <a class="iref" href="#rfc.iref.g.43"><b> 3.5</b></a></li>3103 <li class="indline1"><tt>GMT</tt> <a class="iref" href="#rfc.iref.g.66"><b> 6.1</b></a></li>3104 <li class="indline1"><tt>header-field</tt> <a class="iref" href="#rfc.iref.g.36"><b> 3.2</b></a></li>3127 <li class="indline1"><tt>extension-code</tt> <a class="iref" href="#rfc.iref.g.52"><b>2.9.1.1</b></a></li> 3128 <li class="indline1"><tt>extension-method</tt> <a class="iref" href="#rfc.iref.g.47"><b>2.8.1.1</b></a></li> 3129 <li class="indline1"><tt>field-content</tt> <a class="iref" href="#rfc.iref.g.39"><b>2.7.2</b></a></li> 3130 <li class="indline1"><tt>field-name</tt> <a class="iref" href="#rfc.iref.g.37"><b>2.7.2</b></a></li> 3131 <li class="indline1"><tt>field-value</tt> <a class="iref" href="#rfc.iref.g.38"><b>2.7.2</b></a></li> 3132 <li class="indline1"><tt>general-header</tt> <a class="iref" href="#rfc.iref.g.43"><b>2.7.5</b></a></li> 3133 <li class="indline1"><tt>GMT</tt> <a class="iref" href="#rfc.iref.g.66"><b>2.10.1</b></a></li> 3134 <li class="indline1"><tt>header-field</tt> <a class="iref" href="#rfc.iref.g.36"><b>2.7.2</b></a></li> 3105 3135 <li class="indline1">HEXDIG <a class="iref" href="#rfc.iref.g.7"><b>1.2</b></a></li> 3106 <li class="indline1"><tt>Host</tt> <a class="iref" href="#rfc.iref.g.96"><b> 8.4</b></a></li>3107 <li class="indline1"><tt>Host-v</tt> <a class="iref" href="#rfc.iref.g.97"><b> 8.4</b></a></li>3108 <li class="indline1"><tt>hour</tt> <a class="iref" href="#rfc.iref.g.58"><b> 6.1</b></a></li>3109 <li class="indline1"><tt>HTTP-date</tt> <a class="iref" href="#rfc.iref.g.54"><b> 6.1</b></a></li>3110 <li class="indline1"><tt>HTTP-message</tt> <a class="iref" href="#rfc.iref.g.35"><b> 3</b></a></li>3136 <li class="indline1"><tt>Host</tt> <a class="iref" href="#rfc.iref.g.96"><b>3.4</b></a></li> 3137 <li class="indline1"><tt>Host-v</tt> <a class="iref" href="#rfc.iref.g.97"><b>3.4</b></a></li> 3138 <li class="indline1"><tt>hour</tt> <a class="iref" href="#rfc.iref.g.58"><b>2.10.1</b></a></li> 3139 <li class="indline1"><tt>HTTP-date</tt> <a class="iref" href="#rfc.iref.g.54"><b>2.10.1</b></a></li> 3140 <li class="indline1"><tt>HTTP-message</tt> <a class="iref" href="#rfc.iref.g.35"><b>2.7</b></a></li> 3111 3141 <li class="indline1"><tt>HTTP-Prot-Name</tt> <a class="iref" href="#rfc.iref.g.25"><b>2.5</b></a></li> 3112 3142 <li class="indline1"><tt>http-URI</tt> <a class="iref" href="#rfc.iref.g.33"><b>2.6.1</b></a></li> 3113 3143 <li class="indline1"><tt>HTTP-Version</tt> <a class="iref" href="#rfc.iref.g.24"><b>2.5</b></a></li> 3114 3144 <li class="indline1"><tt>https-URI</tt> <a class="iref" href="#rfc.iref.g.34"><b>2.6.2</b></a></li> 3115 <li class="indline1"><tt>last-chunk</tt> <a class="iref" href="#rfc.iref.g.80"><b> 6.2.1</b></a></li>3145 <li class="indline1"><tt>last-chunk</tt> <a class="iref" href="#rfc.iref.g.80"><b>2.10.2.1</b></a></li> 3116 3146 <li class="indline1">LF <a class="iref" href="#rfc.iref.g.8"><b>1.2</b></a></li> 3117 <li class="indline1"><tt>message-body</tt> <a class="iref" href="#rfc.iref.g.42"><b> 3.3</b></a></li>3118 <li class="indline1"><tt>Method</tt> <a class="iref" href="#rfc.iref.g.46"><b> 4.1.1</b></a></li>3119 <li class="indline1"><tt>minute</tt> <a class="iref" href="#rfc.iref.g.59"><b> 6.1</b></a></li>3120 <li class="indline1"><tt>month</tt> <a class="iref" href="#rfc.iref.g.64"><b> 6.1</b></a></li>3121 <li class="indline1"><tt>obs-date</tt> <a class="iref" href="#rfc.iref.g.67"><b> 6.1</b></a></li>3147 <li class="indline1"><tt>message-body</tt> <a class="iref" href="#rfc.iref.g.42"><b>2.7.3</b></a></li> 3148 <li class="indline1"><tt>Method</tt> <a class="iref" href="#rfc.iref.g.46"><b>2.8.1.1</b></a></li> 3149 <li class="indline1"><tt>minute</tt> <a class="iref" href="#rfc.iref.g.59"><b>2.10.1</b></a></li> 3150 <li class="indline1"><tt>month</tt> <a class="iref" href="#rfc.iref.g.64"><b>2.10.1</b></a></li> 3151 <li class="indline1"><tt>obs-date</tt> <a class="iref" href="#rfc.iref.g.67"><b>2.10.1</b></a></li> 3122 3152 <li class="indline1"><tt>obs-text</tt> <a class="iref" href="#rfc.iref.g.20"><b>1.2.2</b></a></li> 3123 3153 <li class="indline1">OCTET <a class="iref" href="#rfc.iref.g.9"><b>1.2</b></a></li> … … 3125 3155 <li class="indline1"><tt>path-absolute</tt> <a class="iref" href="#rfc.iref.g.29"><b>2.6</b></a></li> 3126 3156 <li class="indline1"><tt>port</tt> <a class="iref" href="#rfc.iref.g.30"><b>2.6</b></a></li> 3127 <li class="indline1"><tt>product</tt> <a class="iref" href="#rfc.iref.g.86"><b> 6.3</b></a></li>3128 <li class="indline1"><tt>product-version</tt> <a class="iref" href="#rfc.iref.g.87"><b> 6.3</b></a></li>3129 <li class="indline1"><tt>protocol-name</tt> <a class="iref" href="#rfc.iref.g.112"><b> 8.9</b></a></li>3130 <li class="indline1"><tt>protocol-version</tt> <a class="iref" href="#rfc.iref.g.113"><b> 8.9</b></a></li>3131 <li class="indline1"><tt>pseudonym</tt> <a class="iref" href="#rfc.iref.g.115"><b> 8.9</b></a></li>3157 <li class="indline1"><tt>product</tt> <a class="iref" href="#rfc.iref.g.86"><b>2.10.3</b></a></li> 3158 <li class="indline1"><tt>product-version</tt> <a class="iref" href="#rfc.iref.g.87"><b>2.10.3</b></a></li> 3159 <li class="indline1"><tt>protocol-name</tt> <a class="iref" href="#rfc.iref.g.112"><b>3.9</b></a></li> 3160 <li class="indline1"><tt>protocol-version</tt> <a class="iref" href="#rfc.iref.g.113"><b>3.9</b></a></li> 3161 <li class="indline1"><tt>pseudonym</tt> <a class="iref" href="#rfc.iref.g.115"><b>3.9</b></a></li> 3132 3162 <li class="indline1"><tt>qdtext</tt> <a class="iref" href="#rfc.iref.g.19"><b>1.2.2</b></a></li> 3133 3163 <li class="indline1"><tt>query</tt> <a class="iref" href="#rfc.iref.g.31"><b>2.6</b></a></li> … … 3135 3165 <li class="indline1"><tt>quoted-string</tt> <a class="iref" href="#rfc.iref.g.18"><b>1.2.2</b></a></li> 3136 3166 <li class="indline1"><tt>quoted-text</tt> <a class="iref" href="#rfc.iref.g.21"><b>1.2.2</b></a></li> 3137 <li class="indline1"><tt>qvalue</tt> <a class="iref" href="#rfc.iref.g.88"><b> 6.4</b></a></li>3138 <li class="indline1"><tt>Reason-Phrase</tt> <a class="iref" href="#rfc.iref.g.53"><b> 5.1.1</b></a></li>3139 <li class="indline1"><tt>received-by</tt> <a class="iref" href="#rfc.iref.g.114"><b> 8.9</b></a></li>3140 <li class="indline1"><tt>received-protocol</tt> <a class="iref" href="#rfc.iref.g.111"><b> 8.9</b></a></li>3141 <li class="indline1"><tt>Request</tt> <a class="iref" href="#rfc.iref.g.44"><b> 4</b></a></li>3142 <li class="indline1"><tt>Request-Line</tt> <a class="iref" href="#rfc.iref.g.45"><b> 4.1</b></a></li>3143 <li class="indline1"><tt>request-target</tt> <a class="iref" href="#rfc.iref.g.48"><b> 4.1.2</b></a></li>3144 <li class="indline1"><tt>Response</tt> <a class="iref" href="#rfc.iref.g.49"><b> 5</b></a></li>3145 <li class="indline1"><tt>rfc1123-date</tt> <a class="iref" href="#rfc.iref.g.55"><b> 6.1</b></a></li>3146 <li class="indline1"><tt>rfc850-date</tt> <a class="iref" href="#rfc.iref.g.68"><b> 6.1</b></a></li>3167 <li class="indline1"><tt>qvalue</tt> <a class="iref" href="#rfc.iref.g.88"><b>2.10.4</b></a></li> 3168 <li class="indline1"><tt>Reason-Phrase</tt> <a class="iref" href="#rfc.iref.g.53"><b>2.9.1.1</b></a></li> 3169 <li class="indline1"><tt>received-by</tt> <a class="iref" href="#rfc.iref.g.114"><b>3.9</b></a></li> 3170 <li class="indline1"><tt>received-protocol</tt> <a class="iref" href="#rfc.iref.g.111"><b>3.9</b></a></li> 3171 <li class="indline1"><tt>Request</tt> <a class="iref" href="#rfc.iref.g.44"><b>2.8</b></a></li> 3172 <li class="indline1"><tt>Request-Line</tt> <a class="iref" href="#rfc.iref.g.45"><b>2.8.1</b></a></li> 3173 <li class="indline1"><tt>request-target</tt> <a class="iref" href="#rfc.iref.g.48"><b>2.8.1.2</b></a></li> 3174 <li class="indline1"><tt>Response</tt> <a class="iref" href="#rfc.iref.g.49"><b>2.9</b></a></li> 3175 <li class="indline1"><tt>rfc1123-date</tt> <a class="iref" href="#rfc.iref.g.55"><b>2.10.1</b></a></li> 3176 <li class="indline1"><tt>rfc850-date</tt> <a class="iref" href="#rfc.iref.g.68"><b>2.10.1</b></a></li> 3147 3177 <li class="indline1"><tt>RWS</tt> <a class="iref" href="#rfc.iref.g.14"><b>1.2.2</b></a></li> 3148 <li class="indline1"><tt>second</tt> <a class="iref" href="#rfc.iref.g.60"><b> 6.1</b></a></li>3178 <li class="indline1"><tt>second</tt> <a class="iref" href="#rfc.iref.g.60"><b>2.10.1</b></a></li> 3149 3179 <li class="indline1">SP <a class="iref" href="#rfc.iref.g.10"><b>1.2</b></a></li> 3150 <li class="indline1"><tt>Status-Code</tt> <a class="iref" href="#rfc.iref.g.51"><b> 5.1.1</b></a></li>3151 <li class="indline1"><tt>Status-Line</tt> <a class="iref" href="#rfc.iref.g.50"><b> 5.1</b></a></li>3152 <li class="indline1"><tt>t-codings</tt> <a class="iref" href="#rfc.iref.g.100"><b> 8.5</b></a></li>3180 <li class="indline1"><tt>Status-Code</tt> <a class="iref" href="#rfc.iref.g.51"><b>2.9.1.1</b></a></li> 3181 <li class="indline1"><tt>Status-Line</tt> <a class="iref" href="#rfc.iref.g.50"><b>2.9.1</b></a></li> 3182 <li class="indline1"><tt>t-codings</tt> <a class="iref" href="#rfc.iref.g.100"><b>3.5</b></a></li> 3153 3183 <li class="indline1"><tt>tchar</tt> <a class="iref" href="#rfc.iref.g.17"><b>1.2.2</b></a></li> 3154 <li class="indline1"><tt>TE</tt> <a class="iref" href="#rfc.iref.g.98"><b> 8.5</b></a></li>3155 <li class="indline1"><tt>te-ext</tt> <a class="iref" href="#rfc.iref.g.102"><b> 8.5</b></a></li>3156 <li class="indline1"><tt>te-params</tt> <a class="iref" href="#rfc.iref.g.101"><b> 8.5</b></a></li>3157 <li class="indline1"><tt>TE-v</tt> <a class="iref" href="#rfc.iref.g.99"><b> 8.5</b></a></li>3158 <li class="indline1"><tt>time-of-day</tt> <a class="iref" href="#rfc.iref.g.57"><b> 6.1</b></a></li>3184 <li class="indline1"><tt>TE</tt> <a class="iref" href="#rfc.iref.g.98"><b>3.5</b></a></li> 3185 <li class="indline1"><tt>te-ext</tt> <a class="iref" href="#rfc.iref.g.102"><b>3.5</b></a></li> 3186 <li class="indline1"><tt>te-params</tt> <a class="iref" href="#rfc.iref.g.101"><b>3.5</b></a></li> 3187 <li class="indline1"><tt>TE-v</tt> <a class="iref" href="#rfc.iref.g.99"><b>3.5</b></a></li> 3188 <li class="indline1"><tt>time-of-day</tt> <a class="iref" href="#rfc.iref.g.57"><b>2.10.1</b></a></li> 3159 3189 <li class="indline1"><tt>token</tt> <a class="iref" href="#rfc.iref.g.16"><b>1.2.2</b></a></li> 3160 <li class="indline1"><tt>Trailer</tt> <a class="iref" href="#rfc.iref.g.103"><b> 8.6</b></a></li>3161 <li class="indline1"><tt>trailer-part</tt> <a class="iref" href="#rfc.iref.g.85"><b> 6.2.1</b></a></li>3162 <li class="indline1"><tt>Trailer-v</tt> <a class="iref" href="#rfc.iref.g.104"><b> 8.6</b></a></li>3163 <li class="indline1"><tt>transfer-coding</tt> <a class="iref" href="#rfc.iref.g.70"><b> 6.2</b></a></li>3164 <li class="indline1"><tt>Transfer-Encoding</tt> <a class="iref" href="#rfc.iref.g.105"><b> 8.7</b></a></li>3165 <li class="indline1"><tt>Transfer-Encoding-v</tt> <a class="iref" href="#rfc.iref.g.106"><b> 8.7</b></a></li>3166 <li class="indline1"><tt>transfer-extension</tt> <a class="iref" href="#rfc.iref.g.71"><b> 6.2</b></a></li>3167 <li class="indline1"><tt>transfer-parameter</tt> <a class="iref" href="#rfc.iref.g.72"><b> 6.2</b></a></li>3168 <li class="indline1"><tt>Upgrade</tt> <a class="iref" href="#rfc.iref.g.107"><b> 8.8</b></a></li>3169 <li class="indline1"><tt>Upgrade-v</tt> <a class="iref" href="#rfc.iref.g.108"><b> 8.8</b></a></li>3190 <li class="indline1"><tt>Trailer</tt> <a class="iref" href="#rfc.iref.g.103"><b>3.6</b></a></li> 3191 <li class="indline1"><tt>trailer-part</tt> <a class="iref" href="#rfc.iref.g.85"><b>2.10.2.1</b></a></li> 3192 <li class="indline1"><tt>Trailer-v</tt> <a class="iref" href="#rfc.iref.g.104"><b>3.6</b></a></li> 3193 <li class="indline1"><tt>transfer-coding</tt> <a class="iref" href="#rfc.iref.g.70"><b>2.10.2</b></a></li> 3194 <li class="indline1"><tt>Transfer-Encoding</tt> <a class="iref" href="#rfc.iref.g.105"><b>3.7</b></a></li> 3195 <li class="indline1"><tt>Transfer-Encoding-v</tt> <a class="iref" href="#rfc.iref.g.106"><b>3.7</b></a></li> 3196 <li class="indline1"><tt>transfer-extension</tt> <a class="iref" href="#rfc.iref.g.71"><b>2.10.2</b></a></li> 3197 <li class="indline1"><tt>transfer-parameter</tt> <a class="iref" href="#rfc.iref.g.72"><b>2.10.2</b></a></li> 3198 <li class="indline1"><tt>Upgrade</tt> <a class="iref" href="#rfc.iref.g.107"><b>3.8</b></a></li> 3199 <li class="indline1"><tt>Upgrade-v</tt> <a class="iref" href="#rfc.iref.g.108"><b>3.8</b></a></li> 3170 3200 <li class="indline1"><tt>uri-host</tt> <a class="iref" href="#rfc.iref.g.32"><b>2.6</b></a></li> 3171 3201 <li class="indline1"><tt>URI-reference</tt> <a class="iref" href="#rfc.iref.g.26"><b>2.6</b></a></li> 3172 <li class="indline1"><tt>value</tt> <a class="iref" href="#rfc.iref.g.74"><b> 6.2</b></a></li>3202 <li class="indline1"><tt>value</tt> <a class="iref" href="#rfc.iref.g.74"><b>2.10.2</b></a></li> 3173 3203 <li class="indline1">VCHAR <a class="iref" href="#rfc.iref.g.11"><b>1.2</b></a></li> 3174 <li class="indline1"><tt>Via</tt> <a class="iref" href="#rfc.iref.g.109"><b> 8.9</b></a></li>3175 <li class="indline1"><tt>Via-v</tt> <a class="iref" href="#rfc.iref.g.110"><b> 8.9</b></a></li>3204 <li class="indline1"><tt>Via</tt> <a class="iref" href="#rfc.iref.g.109"><b>3.9</b></a></li> 3205 <li class="indline1"><tt>Via-v</tt> <a class="iref" href="#rfc.iref.g.110"><b>3.9</b></a></li> 3176 3206 <li class="indline1">WSP <a class="iref" href="#rfc.iref.g.12"><b>1.2</b></a></li> 3177 <li class="indline1"><tt>year</tt> <a class="iref" href="#rfc.iref.g.65"><b> 6.1</b></a></li>3207 <li class="indline1"><tt>year</tt> <a class="iref" href="#rfc.iref.g.65"><b>2.10.1</b></a></li> 3178 3208 </ul> 3179 3209 </li> … … 3181 3211 </li> 3182 3212 <li class="indline0"><a id="rfc.index.H" href="#rfc.index.H"><b>H</b></a><ul class="ind"> 3183 <li class="indline1">header field <a class="iref" href="#rfc.iref.h.5"> 3</a></li>3184 <li class="indline1">header section <a class="iref" href="#rfc.iref.h.3"> 3</a></li>3185 <li class="indline1">headers <a class="iref" href="#rfc.iref.h.4"> 3</a></li>3213 <li class="indline1">header field <a class="iref" href="#rfc.iref.h.5">2.7</a></li> 3214 <li class="indline1">header section <a class="iref" href="#rfc.iref.h.3">2.7</a></li> 3215 <li class="indline1">headers <a class="iref" href="#rfc.iref.h.4">2.7</a></li> 3186 3216 <li class="indline1">Headers 3187 3217 <ul class="ind"> 3188 <li class="indline1">Connection <a class="iref" href="#rfc.xref.header.connection.1"> 3.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">7.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">7.1.3</a>, <a class="iref" href="#rfc.iref.h.6"><b>8.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">8.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">8.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">9.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li>3189 <li class="indline1">Content-Length <a class="iref" href="#rfc.xref.header.content-length.1"> 3.4</a>, <a class="iref" href="#rfc.iref.h.7"><b>8.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">9.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li>3190 <li class="indline1">Date <a class="iref" href="#rfc.xref.header.date.1"> 3.5</a>, <a class="iref" href="#rfc.iref.h.8"><b>8.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">9.1</a></li>3191 <li class="indline1">Host <a class="iref" href="#rfc.iref.h.10"><b> 8.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">9.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li>3192 <li class="indline1">TE <a class="iref" href="#rfc.xref.header.te.1"> 6.2</a>, <a class="iref" href="#rfc.xref.header.te.2">6.2.1</a>, <a class="iref" href="#rfc.xref.header.te.3">6.4</a>, <a class="iref" href="#rfc.iref.h.11"><b>8.5</b></a>, <a class="iref" href="#rfc.xref.header.te.4">9.1</a>, <a class="iref" href="#rfc.xref.header.te.5">B.3</a></li>3193 <li class="indline1">Trailer <a class="iref" href="#rfc.xref.header.trailer.1"> 3.5</a>, <a class="iref" href="#rfc.xref.header.trailer.2">6.2.1</a>, <a class="iref" href="#rfc.iref.h.12"><b>8.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">9.1</a></li>3194 <li class="indline1">Transfer-Encoding <a class="iref" href="#rfc.xref.header.transfer-encoding.1"> 3.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">3.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">3.5</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">6.2</a>, <a class="iref" href="#rfc.iref.h.13"><b>8.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">9.1</a></li>3195 <li class="indline1">Upgrade <a class="iref" href="#rfc.xref.header.upgrade.1"> 3.5</a>, <a class="iref" href="#rfc.iref.h.14"><b>8.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">9.1</a></li>3196 <li class="indline1">Via <a class="iref" href="#rfc.xref.header.via.1"> 3.5</a>, <a class="iref" href="#rfc.iref.h.15"><b>8.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">9.1</a></li>3218 <li class="indline1">Connection <a class="iref" href="#rfc.xref.header.connection.1">2.7.5</a>, <a class="iref" href="#rfc.xref.header.connection.2">2.11.1.2</a>, <a class="iref" href="#rfc.xref.header.connection.3">2.11.1.3</a>, <a class="iref" href="#rfc.iref.h.6"><b>3.1</b></a>, <a class="iref" href="#rfc.xref.header.connection.4">3.5</a>, <a class="iref" href="#rfc.xref.header.connection.5">3.8</a>, <a class="iref" href="#rfc.xref.header.connection.6">4.1</a>, <a class="iref" href="#rfc.xref.header.connection.7">B.2</a>, <a class="iref" href="#rfc.xref.header.connection.8">B.4</a></li> 3219 <li class="indline1">Content-Length <a class="iref" href="#rfc.xref.header.content-length.1">2.7.4</a>, <a class="iref" href="#rfc.iref.h.7"><b>3.2</b></a>, <a class="iref" href="#rfc.xref.header.content-length.2">4.1</a>, <a class="iref" href="#rfc.xref.header.content-length.3">B.3</a></li> 3220 <li class="indline1">Date <a class="iref" href="#rfc.xref.header.date.1">2.7.5</a>, <a class="iref" href="#rfc.iref.h.8"><b>3.3</b></a>, <a class="iref" href="#rfc.xref.header.date.2">4.1</a></li> 3221 <li class="indline1">Host <a class="iref" href="#rfc.iref.h.10"><b>3.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">4.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li> 3222 <li class="indline1">TE <a class="iref" href="#rfc.xref.header.te.1">2.10.2</a>, <a class="iref" href="#rfc.xref.header.te.2">2.10.2.1</a>, <a class="iref" href="#rfc.xref.header.te.3">2.10.4</a>, <a class="iref" href="#rfc.iref.h.11"><b>3.5</b></a>, <a class="iref" href="#rfc.xref.header.te.4">4.1</a>, <a class="iref" href="#rfc.xref.header.te.5">B.3</a></li> 3223 <li class="indline1">Trailer <a class="iref" href="#rfc.xref.header.trailer.1">2.7.5</a>, <a class="iref" href="#rfc.xref.header.trailer.2">2.10.2.1</a>, <a class="iref" href="#rfc.iref.h.12"><b>3.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">4.1</a></li> 3224 <li class="indline1">Transfer-Encoding <a class="iref" href="#rfc.xref.header.transfer-encoding.1">2.7.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">2.7.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">2.7.5</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">2.10.2</a>, <a class="iref" href="#rfc.iref.h.13"><b>3.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">4.1</a></li> 3225 <li class="indline1">Upgrade <a class="iref" href="#rfc.xref.header.upgrade.1">2.7.5</a>, <a class="iref" href="#rfc.iref.h.14"><b>3.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">4.1</a></li> 3226 <li class="indline1">Via <a class="iref" href="#rfc.xref.header.via.1">2.7.5</a>, <a class="iref" href="#rfc.iref.h.15"><b>3.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">4.1</a></li> 3197 3227 </ul> 3198 3228 </li> 3199 <li class="indline1">Host header <a class="iref" href="#rfc.iref.h.9"><b> 8.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">9.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li>3229 <li class="indline1">Host header <a class="iref" href="#rfc.iref.h.9"><b>3.4</b></a>, <a class="iref" href="#rfc.xref.header.host.1">4.1</a>, <a class="iref" href="#rfc.xref.header.host.2">B.1.1</a></li> 3200 3230 <li class="indline1">http URI scheme <a class="iref" href="#rfc.iref.h.1"><b>2.6.1</b></a></li> 3201 3231 <li class="indline1">https URI scheme <a class="iref" href="#rfc.iref.h.2">2.6.2</a></li> … … 3204 3234 <li class="indline0"><a id="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul class="ind"> 3205 3235 <li class="indline1">inbound <a class="iref" href="#rfc.iref.i.1">2.2</a></li> 3206 <li class="indline1"><em>ISO-8859-1</em> <a class="iref" href="#rfc.xref.ISO-8859-1.1"> 3.2</a>, <a class="iref" href="#ISO-8859-1"><b>12.1</b></a></li>3236 <li class="indline1"><em>ISO-8859-1</em> <a class="iref" href="#rfc.xref.ISO-8859-1.1">2.7.2</a>, <a class="iref" href="#ISO-8859-1"><b>7.1</b></a></li> 3207 3237 </ul> 3208 3238 </li> 3209 3239 <li class="indline0"><a id="rfc.index.K" href="#rfc.index.K"><b>K</b></a><ul class="ind"> 3210 <li class="indline1"><em>Kri2001</em> <a class="iref" href="#rfc.xref.Kri2001.1"> 3.2</a>, <a class="iref" href="#Kri2001"><b>12.2</b></a></li>3240 <li class="indline1"><em>Kri2001</em> <a class="iref" href="#rfc.xref.Kri2001.1">2.7.2</a>, <a class="iref" href="#Kri2001"><b>7.2</b></a></li> 3211 3241 </ul> 3212 3242 </li> … … 3214 3244 <li class="indline1">Media Type 3215 3245 <ul class="ind"> 3216 <li class="indline1">application/http <a class="iref" href="#rfc.iref.m.4"><b> 9.3.2</b></a></li>3217 <li class="indline1">message/http <a class="iref" href="#rfc.iref.m.2"><b> 9.3.1</b></a></li>3246 <li class="indline1">application/http <a class="iref" href="#rfc.iref.m.4"><b>4.3.2</b></a></li> 3247 <li class="indline1">message/http <a class="iref" href="#rfc.iref.m.2"><b>4.3.1</b></a></li> 3218 3248 </ul> 3219 3249 </li> 3220 3250 <li class="indline1">message <a class="iref" href="#rfc.iref.m.1">2.1</a></li> 3221 <li class="indline1">message/http Media Type <a class="iref" href="#rfc.iref.m.3"><b> 9.3.1</b></a></li>3251 <li class="indline1">message/http Media Type <a class="iref" href="#rfc.iref.m.3"><b>4.3.1</b></a></li> 3222 3252 </ul> 3223 3253 </li> 3224 3254 <li class="indline0"><a id="rfc.index.N" href="#rfc.index.N"><b>N</b></a><ul class="ind"> 3225 <li class="indline1"><em>Nie1997</em> <a class="iref" href="#rfc.xref.Nie1997.1"> 7.1.1</a>, <a class="iref" href="#Nie1997"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.Nie1997.2">B.3</a></li>3255 <li class="indline1"><em>Nie1997</em> <a class="iref" href="#rfc.xref.Nie1997.1">2.11.1.1</a>, <a class="iref" href="#Nie1997"><b>7.2</b></a>, <a class="iref" href="#rfc.xref.Nie1997.2">B.3</a></li> 3226 3256 </ul> 3227 3257 </li> … … 3232 3262 </li> 3233 3263 <li class="indline0"><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul class="ind"> 3234 <li class="indline1"><em>Pad1995</em> <a class="iref" href="#rfc.xref.Pad1995.1"> 7.1.1</a>, <a class="iref" href="#Pad1995"><b>12.2</b></a></li>3235 <li class="indline1"><em>Part2</em> <a class="iref" href="#rfc.xref.Part2.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.3"> 4</a>, <a class="iref" href="#rfc.xref.Part2.4">4.1.2</a>, <a class="iref" href="#rfc.xref.Part2.5">4.1.2</a>, <a class="iref" href="#rfc.xref.Part2.6">5</a>, <a class="iref" href="#rfc.xref.Part2.7">5.1.1</a>, <a class="iref" href="#rfc.xref.Part2.8">7.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.9">7.1.4</a>, <a class="iref" href="#rfc.xref.Part2.10">7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.11">7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.12">7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.13">7.2.3</a>, <a class="iref" href="#Part2"><b>12.1</b></a><ul class="ind">3236 <li class="indline1"><em>Section 3</em> <a class="iref" href="#rfc.xref.Part2.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.3"> 4</a></li>3237 <li class="indline1"><em>Section 5</em> <a class="iref" href="#rfc.xref.Part2.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.6"> 5</a></li>3238 <li class="indline1"><em>Section 7.1.2</em> <a class="iref" href="#rfc.xref.Part2.8"> 7.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.9">7.1.4</a></li>3239 <li class="indline1"><em>Section 7.9</em> <a class="iref" href="#rfc.xref.Part2.4"> 4.1.2</a></li>3240 <li class="indline1"><em>Section 8</em> <a class="iref" href="#rfc.xref.Part2.7"> 5.1.1</a></li>3241 <li class="indline1"><em>Section 8.1.1</em> <a class="iref" href="#rfc.xref.Part2.10"> 7.2.3</a></li>3242 <li class="indline1"><em>Section 8.1</em> <a class="iref" href="#rfc.xref.Part2.13"> 7.2.3</a></li>3243 <li class="indline1"><em>Section 8.4.15</em> <a class="iref" href="#rfc.xref.Part2.5"> 4.1.2</a></li>3244 <li class="indline1"><em>Section 9.2</em> <a class="iref" href="#rfc.xref.Part2.11"> 7.2.3</a>, <a class="iref" href="#rfc.xref.Part2.12">7.2.3</a></li>3264 <li class="indline1"><em>Pad1995</em> <a class="iref" href="#rfc.xref.Pad1995.1">2.11.1.1</a>, <a class="iref" href="#Pad1995"><b>7.2</b></a></li> 3265 <li class="indline1"><em>Part2</em> <a class="iref" href="#rfc.xref.Part2.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.3">2.8</a>, <a class="iref" href="#rfc.xref.Part2.4">2.8.1.2</a>, <a class="iref" href="#rfc.xref.Part2.5">2.8.1.2</a>, <a class="iref" href="#rfc.xref.Part2.6">2.9</a>, <a class="iref" href="#rfc.xref.Part2.7">2.9.1.1</a>, <a class="iref" href="#rfc.xref.Part2.8">2.11.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.9">2.11.1.4</a>, <a class="iref" href="#rfc.xref.Part2.10">2.11.2.3</a>, <a class="iref" href="#rfc.xref.Part2.11">2.11.2.3</a>, <a class="iref" href="#rfc.xref.Part2.12">2.11.2.3</a>, <a class="iref" href="#rfc.xref.Part2.13">2.11.2.3</a>, <a class="iref" href="#Part2"><b>7.1</b></a><ul class="ind"> 3266 <li class="indline1"><em>Section 3</em> <a class="iref" href="#rfc.xref.Part2.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.3">2.8</a></li> 3267 <li class="indline1"><em>Section 5</em> <a class="iref" href="#rfc.xref.Part2.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part2.6">2.9</a></li> 3268 <li class="indline1"><em>Section 7.1.2</em> <a class="iref" href="#rfc.xref.Part2.8">2.11.1.2.2</a>, <a class="iref" href="#rfc.xref.Part2.9">2.11.1.4</a></li> 3269 <li class="indline1"><em>Section 7.9</em> <a class="iref" href="#rfc.xref.Part2.4">2.8.1.2</a></li> 3270 <li class="indline1"><em>Section 8</em> <a class="iref" href="#rfc.xref.Part2.7">2.9.1.1</a></li> 3271 <li class="indline1"><em>Section 8.1.1</em> <a class="iref" href="#rfc.xref.Part2.10">2.11.2.3</a></li> 3272 <li class="indline1"><em>Section 8.1</em> <a class="iref" href="#rfc.xref.Part2.13">2.11.2.3</a></li> 3273 <li class="indline1"><em>Section 8.4.15</em> <a class="iref" href="#rfc.xref.Part2.5">2.8.1.2</a></li> 3274 <li class="indline1"><em>Section 9.2</em> <a class="iref" href="#rfc.xref.Part2.11">2.11.2.3</a>, <a class="iref" href="#rfc.xref.Part2.12">2.11.2.3</a></li> 3245 3275 </ul> 3246 3276 </li> 3247 <li class="indline1"><em>Part3</em> <a class="iref" href="#rfc.xref.Part3.1">1</a>, <a class="iref" href="#rfc.xref.Part3.2">1.2.2</a>, <a class="iref" href="#rfc.xref.Part3.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.4">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.5"> 4</a>, <a class="iref" href="#rfc.xref.Part3.6">5</a>, <a class="iref" href="#rfc.xref.Part3.7">6.2</a>, <a class="iref" href="#rfc.xref.Part3.8">6.2</a>, <a class="iref" href="#rfc.xref.Part3.9">6.4</a>, <a class="iref" href="#Part3"><b>12.1</b></a>, <a class="iref" href="#rfc.xref.Part3.10">A</a>, <a class="iref" href="#rfc.xref.Part3.11">B.3</a>, <a class="iref" href="#rfc.xref.Part3.12">C</a>, <a class="iref" href="#rfc.xref.Part3.13">C</a>, <a class="iref" href="#rfc.xref.Part3.14">C</a><ul class="ind">3248 <li class="indline1"><em>Section 2.2</em> <a class="iref" href="#rfc.xref.Part3.7"> 6.2</a>, <a class="iref" href="#rfc.xref.Part3.8">6.2</a></li>3277 <li class="indline1"><em>Part3</em> <a class="iref" href="#rfc.xref.Part3.1">1</a>, <a class="iref" href="#rfc.xref.Part3.2">1.2.2</a>, <a class="iref" href="#rfc.xref.Part3.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.4">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.5">2.8</a>, <a class="iref" href="#rfc.xref.Part3.6">2.9</a>, <a class="iref" href="#rfc.xref.Part3.7">2.10.2</a>, <a class="iref" href="#rfc.xref.Part3.8">2.10.2</a>, <a class="iref" href="#rfc.xref.Part3.9">2.10.4</a>, <a class="iref" href="#Part3"><b>7.1</b></a>, <a class="iref" href="#rfc.xref.Part3.10">A</a>, <a class="iref" href="#rfc.xref.Part3.11">B.3</a>, <a class="iref" href="#rfc.xref.Part3.12">C</a>, <a class="iref" href="#rfc.xref.Part3.13">C</a>, <a class="iref" href="#rfc.xref.Part3.14">C</a><ul class="ind"> 3278 <li class="indline1"><em>Section 2.2</em> <a class="iref" href="#rfc.xref.Part3.7">2.10.2</a>, <a class="iref" href="#rfc.xref.Part3.8">2.10.2</a></li> 3249 3279 <li class="indline1"><em>Section 2.3</em> <a class="iref" href="#rfc.xref.Part3.2">1.2.2</a></li> 3250 <li class="indline1"><em>Section 3.1</em> <a class="iref" href="#rfc.xref.Part3.4">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.5"> 4</a>, <a class="iref" href="#rfc.xref.Part3.6">5</a></li>3280 <li class="indline1"><em>Section 3.1</em> <a class="iref" href="#rfc.xref.Part3.4">1.2.3</a>, <a class="iref" href="#rfc.xref.Part3.5">2.8</a>, <a class="iref" href="#rfc.xref.Part3.6">2.9</a></li> 3251 3281 <li class="indline1"><em>Section 3</em> <a class="iref" href="#rfc.xref.Part3.13">C</a></li> 3252 3282 <li class="indline1"><em>Section 3.2</em> <a class="iref" href="#rfc.xref.Part3.3">1.2.3</a></li> 3253 <li class="indline1"><em>Section 4</em> <a class="iref" href="#rfc.xref.Part3.9"> 6.4</a>, <a class="iref" href="#rfc.xref.Part3.12">C</a>, <a class="iref" href="#rfc.xref.Part3.14">C</a></li>3283 <li class="indline1"><em>Section 4</em> <a class="iref" href="#rfc.xref.Part3.9">2.10.4</a>, <a class="iref" href="#rfc.xref.Part3.12">C</a>, <a class="iref" href="#rfc.xref.Part3.14">C</a></li> 3254 3284 <li class="indline1"><em>Appendix A</em> <a class="iref" href="#rfc.xref.Part3.1">1</a></li> 3255 3285 </ul> 3256 3286 </li> 3257 <li class="indline1"><em>Part5</em> <a class="iref" href="#Part5"><b> 12.1</b></a>, <a class="iref" href="#rfc.xref.Part5.1">B.3</a></li>3258 <li class="indline1"><em>Part6</em> <a class="iref" href="#rfc.xref.Part6.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.4">2.3</a>, <a class="iref" href="#rfc.xref.Part6.5"> 3.5</a>, <a class="iref" href="#rfc.xref.Part6.6">3.5</a>, <a class="iref" href="#rfc.xref.Part6.7">3.5</a>, <a class="iref" href="#Part6"><b>12.1</b></a>, <a class="iref" href="#rfc.xref.Part6.8">B.3</a><ul class="ind">3287 <li class="indline1"><em>Part5</em> <a class="iref" href="#Part5"><b>7.1</b></a>, <a class="iref" href="#rfc.xref.Part5.1">B.3</a></li> 3288 <li class="indline1"><em>Part6</em> <a class="iref" href="#rfc.xref.Part6.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.4">2.3</a>, <a class="iref" href="#rfc.xref.Part6.5">2.7.5</a>, <a class="iref" href="#rfc.xref.Part6.6">2.7.5</a>, <a class="iref" href="#rfc.xref.Part6.7">2.7.5</a>, <a class="iref" href="#Part6"><b>7.1</b></a>, <a class="iref" href="#rfc.xref.Part6.8">B.3</a><ul class="ind"> 3259 3289 <li class="indline1"><em>Section 2</em> <a class="iref" href="#rfc.xref.Part6.4">2.3</a></li> 3260 <li class="indline1"><em>Section 3.2</em> <a class="iref" href="#rfc.xref.Part6.5"> 3.5</a></li>3261 <li class="indline1"><em>Section 3.4</em> <a class="iref" href="#rfc.xref.Part6.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.6"> 3.5</a></li>3262 <li class="indline1"><em>Section 3.6</em> <a class="iref" href="#rfc.xref.Part6.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.7"> 3.5</a></li>3290 <li class="indline1"><em>Section 3.2</em> <a class="iref" href="#rfc.xref.Part6.5">2.7.5</a></li> 3291 <li class="indline1"><em>Section 3.4</em> <a class="iref" href="#rfc.xref.Part6.1">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.2">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.6">2.7.5</a></li> 3292 <li class="indline1"><em>Section 3.6</em> <a class="iref" href="#rfc.xref.Part6.3">1.2.3</a>, <a class="iref" href="#rfc.xref.Part6.7">2.7.5</a></li> 3263 3293 </ul> 3264 3294 </li> … … 3272 3302 <li class="indline1">response <a class="iref" href="#rfc.iref.r.2">2.1</a></li> 3273 3303 <li class="indline1">reverse proxy <a class="iref" href="#rfc.iref.r.3">2.2</a></li> 3274 <li class="indline1"><em>RFC1123</em> <a class="iref" href="#rfc.xref.RFC1123.1"> 6.1</a>, <a class="iref" href="#RFC1123"><b>12.2</b></a></li>3275 <li class="indline1"><em>RFC1305</em> <a class="iref" href="#rfc.xref.RFC1305.1"> 8.3</a>, <a class="iref" href="#RFC1305"><b>12.2</b></a></li>3276 <li class="indline1"><em>RFC1900</em> <a class="iref" href="#rfc.xref.RFC1900.1"> 10.4</a>, <a class="iref" href="#RFC1900"><b>12.2</b></a></li>3277 <li class="indline1"><em>RFC1945</em> <a class="iref" href="#RFC1945"><b> 12.2</b></a>, <a class="iref" href="#rfc.xref.RFC1945.1">B</a></li>3278 <li class="indline1"><em>RFC2045</em> <a class="iref" href="#rfc.xref.RFC2045.1">1</a>, <a class="iref" href="#rfc.xref.RFC2045.2"> 6.2</a>, <a class="iref" href="#rfc.xref.RFC2045.3">11</a>, <a class="iref" href="#RFC2045"><b>12.2</b></a><ul class="ind">3279 <li class="indline1"><em>Section 6</em> <a class="iref" href="#rfc.xref.RFC2045.2"> 6.2</a></li>3304 <li class="indline1"><em>RFC1123</em> <a class="iref" href="#rfc.xref.RFC1123.1">2.10.1</a>, <a class="iref" href="#RFC1123"><b>7.2</b></a></li> 3305 <li class="indline1"><em>RFC1305</em> <a class="iref" href="#rfc.xref.RFC1305.1">3.3</a>, <a class="iref" href="#RFC1305"><b>7.2</b></a></li> 3306 <li class="indline1"><em>RFC1900</em> <a class="iref" href="#rfc.xref.RFC1900.1">5.4</a>, <a class="iref" href="#RFC1900"><b>7.2</b></a></li> 3307 <li class="indline1"><em>RFC1945</em> <a class="iref" href="#RFC1945"><b>7.2</b></a>, <a class="iref" href="#rfc.xref.RFC1945.1">B</a></li> 3308 <li class="indline1"><em>RFC2045</em> <a class="iref" href="#rfc.xref.RFC2045.1">1</a>, <a class="iref" href="#rfc.xref.RFC2045.2">2.10.2</a>, <a class="iref" href="#rfc.xref.RFC2045.3">6</a>, <a class="iref" href="#RFC2045"><b>7.2</b></a><ul class="ind"> 3309 <li class="indline1"><em>Section 6</em> <a class="iref" href="#rfc.xref.RFC2045.2">2.10.2</a></li> 3280 3310 </ul> 3281 3311 </li> 3282 <li class="indline1"><em>RFC2047</em> <a class="iref" href="#rfc.xref.RFC2047.1"> 3.2</a>, <a class="iref" href="#RFC2047"><b>12.2</b></a></li>3283 <li class="indline1"><em>RFC2068</em> <a class="iref" href="#rfc.xref.RFC2068.1">2.5</a>, <a class="iref" href="#rfc.xref.RFC2068.2"> 7.1.3</a>, <a class="iref" href="#rfc.xref.RFC2068.3">7.2.3</a>, <a class="iref" href="#rfc.xref.RFC2068.4">11</a>, <a class="iref" href="#RFC2068"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.RFC2068.5">B</a>, <a class="iref" href="#rfc.xref.RFC2068.6">B.2</a><ul class="ind">3284 <li class="indline1"><em>Section 19.7.1</em> <a class="iref" href="#rfc.xref.RFC2068.2"> 7.1.3</a>, <a class="iref" href="#rfc.xref.RFC2068.5">B</a>, <a class="iref" href="#rfc.xref.RFC2068.6">B.2</a></li>3312 <li class="indline1"><em>RFC2047</em> <a class="iref" href="#rfc.xref.RFC2047.1">2.7.2</a>, <a class="iref" href="#RFC2047"><b>7.2</b></a></li> 3313 <li class="indline1"><em>RFC2068</em> <a class="iref" href="#rfc.xref.RFC2068.1">2.5</a>, <a class="iref" href="#rfc.xref.RFC2068.2">2.11.1.3</a>, <a class="iref" href="#rfc.xref.RFC2068.3">2.11.2.3</a>, <a class="iref" href="#rfc.xref.RFC2068.4">6</a>, <a class="iref" href="#RFC2068"><b>7.2</b></a>, <a class="iref" href="#rfc.xref.RFC2068.5">B</a>, <a class="iref" href="#rfc.xref.RFC2068.6">B.2</a><ul class="ind"> 3314 <li class="indline1"><em>Section 19.7.1</em> <a class="iref" href="#rfc.xref.RFC2068.2">2.11.1.3</a>, <a class="iref" href="#rfc.xref.RFC2068.5">B</a>, <a class="iref" href="#rfc.xref.RFC2068.6">B.2</a></li> 3285 3315 </ul> 3286 3316 </li> 3287 <li class="indline1"><em>RFC2109</em> <a class="iref" href="#rfc.xref.RFC2109.1"> 3.2</a>, <a class="iref" href="#RFC2109"><b>12.2</b></a></li>3288 <li class="indline1"><em>RFC2119</em> <a class="iref" href="#rfc.xref.RFC2119.1">1.1</a>, <a class="iref" href="#RFC2119"><b> 12.1</b></a>, <a class="iref" href="#rfc.xref.RFC2119.2">B.3</a></li>3289 <li class="indline1"><em>RFC2145</em> <a class="iref" href="#rfc.xref.RFC2145.1">2.5</a>, <a class="iref" href="#rfc.xref.RFC2145.2">2.5</a>, <a class="iref" href="#RFC2145"><b> 12.2</b></a>, <a class="iref" href="#rfc.xref.RFC2145.3">B.3</a></li>3290 <li class="indline1"><em>RFC2616</em> <a class="iref" href="#rfc.xref.RFC2616.1">1</a>, <a class="iref" href="#rfc.xref.RFC2616.2"> 11</a>, <a class="iref" href="#RFC2616"><b>12.2</b></a>, <a class="iref" href="#rfc.xref.RFC2616.3">E.1</a></li>3291 <li class="indline1"><em>RFC2818</em> <a class="iref" href="#rfc.xref.RFC2818.1">2.6.2</a>, <a class="iref" href="#RFC2818"><b> 12.2</b></a></li>3292 <li class="indline1"><em>RFC2965</em> <a class="iref" href="#rfc.xref.RFC2965.1"> 3.2</a>, <a class="iref" href="#RFC2965"><b>12.2</b></a></li>3293 <li class="indline1"><em>RFC3864</em> <a class="iref" href="#rfc.xref.RFC3864.1"> 9.1</a>, <a class="iref" href="#RFC3864"><b>12.2</b></a></li>3294 <li class="indline1"><em>RFC3986</em> <a class="iref" href="#rfc.xref.RFC3986.1">1</a>, <a class="iref" href="#rfc.xref.RFC3986.2">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.3">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.4">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.5">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.6">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.7">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.8">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.9">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.10">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.11">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.12">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.13">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.14">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.15">2.6.1</a>, <a class="iref" href="#rfc.xref.RFC3986.16">2.6.3</a>, <a class="iref" href="#rfc.xref.RFC3986.17">2.6.3</a>, <a class="iref" href="#rfc.xref.RFC3986.18"> 4.1.2</a>, <a class="iref" href="#RFC3986"><b>12.1</b></a><ul class="ind">3295 <li class="indline1"><em>Section 2.1</em> <a class="iref" href="#rfc.xref.RFC3986.17">2.6.3</a>, <a class="iref" href="#rfc.xref.RFC3986.18"> 4.1.2</a></li>3317 <li class="indline1"><em>RFC2109</em> <a class="iref" href="#rfc.xref.RFC2109.1">2.7.2</a>, <a class="iref" href="#RFC2109"><b>7.2</b></a></li> 3318 <li class="indline1"><em>RFC2119</em> <a class="iref" href="#rfc.xref.RFC2119.1">1.1</a>, <a class="iref" href="#RFC2119"><b>7.1</b></a>, <a class="iref" href="#rfc.xref.RFC2119.2">B.3</a></li> 3319 <li class="indline1"><em>RFC2145</em> <a class="iref" href="#rfc.xref.RFC2145.1">2.5</a>, <a class="iref" href="#rfc.xref.RFC2145.2">2.5</a>, <a class="iref" href="#RFC2145"><b>7.2</b></a>, <a class="iref" href="#rfc.xref.RFC2145.3">B.3</a></li> 3320 <li class="indline1"><em>RFC2616</em> <a class="iref" href="#rfc.xref.RFC2616.1">1</a>, <a class="iref" href="#rfc.xref.RFC2616.2">6</a>, <a class="iref" href="#RFC2616"><b>7.2</b></a>, <a class="iref" href="#rfc.xref.RFC2616.3">E.1</a></li> 3321 <li class="indline1"><em>RFC2818</em> <a class="iref" href="#rfc.xref.RFC2818.1">2.6.2</a>, <a class="iref" href="#RFC2818"><b>7.2</b></a></li> 3322 <li class="indline1"><em>RFC2965</em> <a class="iref" href="#rfc.xref.RFC2965.1">2.7.2</a>, <a class="iref" href="#RFC2965"><b>7.2</b></a></li> 3323 <li class="indline1"><em>RFC3864</em> <a class="iref" href="#rfc.xref.RFC3864.1">4.1</a>, <a class="iref" href="#RFC3864"><b>7.2</b></a></li> 3324 <li class="indline1"><em>RFC3986</em> <a class="iref" href="#rfc.xref.RFC3986.1">1</a>, <a class="iref" href="#rfc.xref.RFC3986.2">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.3">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.4">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.5">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.6">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.7">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.8">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.9">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.10">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.11">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.12">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.13">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.14">2.6</a>, <a class="iref" href="#rfc.xref.RFC3986.15">2.6.1</a>, <a class="iref" href="#rfc.xref.RFC3986.16">2.6.3</a>, <a class="iref" href="#rfc.xref.RFC3986.17">2.6.3</a>, <a class="iref" href="#rfc.xref.RFC3986.18">2.8.1.2</a>, <a class="iref" href="#RFC3986"><b>7.1</b></a><ul class="ind"> 3325 <li class="indline1"><em>Section 2.1</em> <a class="iref" href="#rfc.xref.RFC3986.17">2.6.3</a>, <a class="iref" href="#rfc.xref.RFC3986.18">2.8.1.2</a></li> 3296 3326 <li class="indline1"><em>Section 3</em> <a class="iref" href="#rfc.xref.RFC3986.5">2.6</a></li> 3297 3327 <li class="indline1"><em>Section 3.2</em> <a class="iref" href="#rfc.xref.RFC3986.9">2.6</a></li> … … 3306 3336 </ul> 3307 3337 </li> 3308 <li class="indline1"><em>RFC4288</em> <a class="iref" href="#rfc.xref.RFC4288.1"> 9.3</a>, <a class="iref" href="#RFC4288"><b>12.2</b></a></li>3309 <li class="indline1"><em>RFC4395</em> <a class="iref" href="#rfc.xref.RFC4395.1"> 9.2</a>, <a class="iref" href="#RFC4395"><b>12.2</b></a></li>3310 <li class="indline1"><em>RFC5234</em> <a class="iref" href="#rfc.xref.RFC5234.1">1.2</a>, <a class="iref" href="#rfc.xref.RFC5234.2">1.2</a>, <a class="iref" href="#rfc.xref.RFC5234.3">1.2.1</a>, <a class="iref" href="#rfc.xref.RFC5234.4"> 11</a>, <a class="iref" href="#RFC5234"><b>12.1</b></a><ul class="ind">3338 <li class="indline1"><em>RFC4288</em> <a class="iref" href="#rfc.xref.RFC4288.1">4.3</a>, <a class="iref" href="#RFC4288"><b>7.2</b></a></li> 3339 <li class="indline1"><em>RFC4395</em> <a class="iref" href="#rfc.xref.RFC4395.1">4.2</a>, <a class="iref" href="#RFC4395"><b>7.2</b></a></li> 3340 <li class="indline1"><em>RFC5234</em> <a class="iref" href="#rfc.xref.RFC5234.1">1.2</a>, <a class="iref" href="#rfc.xref.RFC5234.2">1.2</a>, <a class="iref" href="#rfc.xref.RFC5234.3">1.2.1</a>, <a class="iref" href="#rfc.xref.RFC5234.4">6</a>, <a class="iref" href="#RFC5234"><b>7.1</b></a><ul class="ind"> 3311 3341 <li class="indline1"><em>Appendix B.1</em> <a class="iref" href="#rfc.xref.RFC5234.2">1.2</a></li> 3312 3342 </ul> 3313 3343 </li> 3314 <li class="indline1"><em>RFC5322</em> <a class="iref" href="#rfc.xref.RFC5322.1">1</a>, <a class="iref" href="#rfc.xref.RFC5322.2"> 3</a>, <a class="iref" href="#rfc.xref.RFC5322.3">6.1</a>, <a class="iref" href="#rfc.xref.RFC5322.4">8.3</a>, <a class="iref" href="#rfc.xref.RFC5322.5">8.9</a>, <a class="iref" href="#RFC5322"><b>12.2</b></a><ul class="ind">3315 <li class="indline1"><em>Section 3.3</em> <a class="iref" href="#rfc.xref.RFC5322.3"> 6.1</a></li>3316 <li class="indline1"><em>Section 3.6.1</em> <a class="iref" href="#rfc.xref.RFC5322.4"> 8.3</a></li>3317 <li class="indline1"><em>Section 3.6.7</em> <a class="iref" href="#rfc.xref.RFC5322.5"> 8.9</a></li>3344 <li class="indline1"><em>RFC5322</em> <a class="iref" href="#rfc.xref.RFC5322.1">1</a>, <a class="iref" href="#rfc.xref.RFC5322.2">2.7</a>, <a class="iref" href="#rfc.xref.RFC5322.3">2.10.1</a>, <a class="iref" href="#rfc.xref.RFC5322.4">3.3</a>, <a class="iref" href="#rfc.xref.RFC5322.5">3.9</a>, <a class="iref" href="#RFC5322"><b>7.2</b></a><ul class="ind"> 3345 <li class="indline1"><em>Section 3.3</em> <a class="iref" href="#rfc.xref.RFC5322.3">2.10.1</a></li> 3346 <li class="indline1"><em>Section 3.6.1</em> <a class="iref" href="#rfc.xref.RFC5322.4">3.3</a></li> 3347 <li class="indline1"><em>Section 3.6.7</em> <a class="iref" href="#rfc.xref.RFC5322.5">3.9</a></li> 3318 3348 </ul> 3319 3349 </li> … … 3322 3352 <li class="indline0"><a id="rfc.index.S" href="#rfc.index.S"><b>S</b></a><ul class="ind"> 3323 3353 <li class="indline1">server <a class="iref" href="#rfc.iref.s.1">2.1</a></li> 3324 <li class="indline1"><em>Spe</em> <a class="iref" href="#rfc.xref.Spe.1"> 7.1.1</a>, <a class="iref" href="#Spe"><b>12.2</b></a></li>3354 <li class="indline1"><em>Spe</em> <a class="iref" href="#rfc.xref.Spe.1">2.11.1.1</a>, <a class="iref" href="#Spe"><b>7.2</b></a></li> 3325 3355 </ul> 3326 3356 </li> 3327 3357 <li class="indline0"><a id="rfc.index.T" href="#rfc.index.T"><b>T</b></a><ul class="ind"> 3328 <li class="indline1">TE header <a class="iref" href="#rfc.xref.header.te.1"> 6.2</a>, <a class="iref" href="#rfc.xref.header.te.2">6.2.1</a>, <a class="iref" href="#rfc.xref.header.te.3">6.4</a>, <a class="iref" href="#rfc.iref.t.2"><b>8.5</b></a>, <a class="iref" href="#rfc.xref.header.te.4">9.1</a>, <a class="iref" href="#rfc.xref.header.te.5">B.3</a></li>3329 <li class="indline1"><em>Tou1998</em> <a class="iref" href="#rfc.xref.Tou1998.1"> 7.1.1</a>, <a class="iref" href="#Tou1998"><b>12.2</b></a></li>3330 <li class="indline1">Trailer header <a class="iref" href="#rfc.xref.header.trailer.1"> 3.5</a>, <a class="iref" href="#rfc.xref.header.trailer.2">6.2.1</a>, <a class="iref" href="#rfc.iref.t.3"><b>8.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">9.1</a></li>3331 <li class="indline1">Transfer-Encoding header <a class="iref" href="#rfc.xref.header.transfer-encoding.1"> 3.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">3.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">3.5</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">6.2</a>, <a class="iref" href="#rfc.iref.t.4"><b>8.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">9.1</a></li>3358 <li class="indline1">TE header <a class="iref" href="#rfc.xref.header.te.1">2.10.2</a>, <a class="iref" href="#rfc.xref.header.te.2">2.10.2.1</a>, <a class="iref" href="#rfc.xref.header.te.3">2.10.4</a>, <a class="iref" href="#rfc.iref.t.2"><b>3.5</b></a>, <a class="iref" href="#rfc.xref.header.te.4">4.1</a>, <a class="iref" href="#rfc.xref.header.te.5">B.3</a></li> 3359 <li class="indline1"><em>Tou1998</em> <a class="iref" href="#rfc.xref.Tou1998.1">2.11.1.1</a>, <a class="iref" href="#Tou1998"><b>7.2</b></a></li> 3360 <li class="indline1">Trailer header <a class="iref" href="#rfc.xref.header.trailer.1">2.7.5</a>, <a class="iref" href="#rfc.xref.header.trailer.2">2.10.2.1</a>, <a class="iref" href="#rfc.iref.t.3"><b>3.6</b></a>, <a class="iref" href="#rfc.xref.header.trailer.3">4.1</a></li> 3361 <li class="indline1">Transfer-Encoding header <a class="iref" href="#rfc.xref.header.transfer-encoding.1">2.7.3</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.2">2.7.4</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.3">2.7.5</a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.4">2.10.2</a>, <a class="iref" href="#rfc.iref.t.4"><b>3.7</b></a>, <a class="iref" href="#rfc.xref.header.transfer-encoding.5">4.1</a></li> 3332 3362 <li class="indline1">tunnel <a class="iref" href="#rfc.iref.t.1">2.2</a></li> 3333 3363 </ul> 3334 3364 </li> 3335 3365 <li class="indline0"><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul class="ind"> 3336 <li class="indline1">Upgrade header <a class="iref" href="#rfc.xref.header.upgrade.1"> 3.5</a>, <a class="iref" href="#rfc.iref.u.5"><b>8.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">9.1</a></li>3366 <li class="indline1">Upgrade header <a class="iref" href="#rfc.xref.header.upgrade.1">2.7.5</a>, <a class="iref" href="#rfc.iref.u.5"><b>3.8</b></a>, <a class="iref" href="#rfc.xref.header.upgrade.2">4.1</a></li> 3337 3367 <li class="indline1">upstream <a class="iref" href="#rfc.iref.u.2">2.2</a></li> 3338 3368 <li class="indline1">URI scheme … … 3342 3372 </ul> 3343 3373 </li> 3344 <li class="indline1"><em>USASCII</em> <a class="iref" href="#rfc.xref.USASCII.1">1.2</a>, <a class="iref" href="#rfc.xref.USASCII.2"> 3.2</a>, <a class="iref" href="#USASCII"><b>12.1</b></a></li>3374 <li class="indline1"><em>USASCII</em> <a class="iref" href="#rfc.xref.USASCII.1">1.2</a>, <a class="iref" href="#rfc.xref.USASCII.2">2.7.2</a>, <a class="iref" href="#USASCII"><b>7.1</b></a></li> 3345 3375 <li class="indline1">user agent <a class="iref" href="#rfc.iref.u.1">2.1</a></li> 3346 3376 </ul> … … 3348 3378 <li class="indline0"><a id="rfc.index.V" href="#rfc.index.V"><b>V</b></a><ul class="ind"> 3349 3379 <li class="indline1">variant <a class="iref" href="#rfc.iref.v.2">C</a></li> 3350 <li class="indline1">Via header <a class="iref" href="#rfc.xref.header.via.1"> 3.5</a>, <a class="iref" href="#rfc.iref.v.1"><b>8.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">9.1</a></li>3380 <li class="indline1">Via header <a class="iref" href="#rfc.xref.header.via.1">2.7.5</a>, <a class="iref" href="#rfc.iref.v.1"><b>3.9</b></a>, <a class="iref" href="#rfc.xref.header.via.2">4.1</a></li> 3351 3381 </ul> 3352 3382 </li> -
draft-ietf-httpbis/latest/p1-messaging.xml
r650 r651 985 985 </t> 986 986 </section> 987 988 <section title="Scheme aliases considered harmful" anchor="scheme.aliases">989 <t>990 <cref>TBS: describe why aliases like webcal are harmful.</cref>991 </t>992 </section>993 </section>994 995 <section title="Use of HTTP for proxy communication" anchor="http.proxy">996 <t>997 <cref>TBD: Configured to use HTTP to proxy HTTP or other protocols.</cref>998 </t>999 </section>1000 <section title="Interception of HTTP for access control" anchor="http.intercept">1001 <t>1002 <cref>TBD: Interception of HTTP traffic for initiating access control.</cref>1003 </t>1004 </section>1005 <section title="Use of HTTP by other protocols" anchor="http.others">1006 <t>1007 <cref>TBD: Profiles of HTTP defined by other protocol.1008 Extensions of HTTP like WebDAV.</cref>1009 </t>1010 </section>1011 <section title="Use of HTTP by media type specification" anchor="http.media">1012 <t>1013 <cref>TBD: Instructions on composing HTTP requests via hypertext formats.</cref>1014 </t>1015 </section>1016 987 </section> 1017 988 … … 1135 1106 </t> 1136 1107 <t> 1137 Multiple header fields with the same field name &M AY; be1138 sent in a message if and only ifthe entire field value for that1108 Multiple header fields with the same field name &MUST-NOT; be 1109 sent in a message unless the entire field value for that 1139 1110 header field is defined as a comma-separated list [i.e., #(values)]. 1140 1111 Multiple header fields with the same field name can be combined into … … 2398 2369 </section> 2399 2370 2371 2372 <section title="Miscellaneous notes that may disappear" anchor="misc"> 2373 <section title="Scheme aliases considered harmful" anchor="scheme.aliases"> 2374 <t> 2375 <cref>TBS: describe why aliases like webcal are harmful.</cref> 2376 </t> 2377 </section> 2378 </section> 2379 2380 <section title="Use of HTTP for proxy communication" anchor="http.proxy"> 2381 <t> 2382 <cref>TBD: Configured to use HTTP to proxy HTTP or other protocols.</cref> 2383 </t> 2384 </section> 2385 <section title="Interception of HTTP for access control" anchor="http.intercept"> 2386 <t> 2387 <cref>TBD: Interception of HTTP traffic for initiating access control.</cref> 2388 </t> 2389 </section> 2390 <section title="Use of HTTP by other protocols" anchor="http.others"> 2391 <t> 2392 <cref>TBD: Profiles of HTTP defined by other protocol. 2393 Extensions of HTTP like WebDAV.</cref> 2394 </t> 2395 </section> 2396 <section title="Use of HTTP by media type specification" anchor="http.media"> 2397 <t> 2398 <cref>TBD: Instructions on composing HTTP requests via hypertext formats.</cref> 2399 </t> 2400 </section> 2401 </section> 2400 2402 2401 2403 <section title="Header Field Definitions" anchor="header.field.definitions">
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