Changeset 2066 for draft-ietf-httpbis/latest/p4-conditional.html
- Timestamp:
- 29/12/12 10:14:11 (10 years ago)
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draft-ietf-httpbis/latest/p4-conditional.html
r2052 r2066 449 449 } 450 450 @bottom-center { 451 content: "Expires Ju ne 18, 2013";451 content: "Expires July 2, 2013"; 452 452 } 453 453 @bottom-right { … … 491 491 <meta name="dct.creator" content="Reschke, J. F."> 492 492 <meta name="dct.identifier" content="urn:ietf:id:draft-ietf-httpbis-p4-conditional-latest"> 493 <meta name="dct.issued" scheme="ISO8601" content="2012-12- 15">493 <meta name="dct.issued" scheme="ISO8601" content="2012-12-29"> 494 494 <meta name="dct.replaces" content="urn:ietf:rfc:2616"> 495 495 <meta name="dct.abstract" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypertext information systems. This document defines HTTP/1.1 conditional requests, including metadata header fields for indicating state changes, request header fields for making preconditions on such state, and rules for constructing the responses to a conditional request when one or more preconditions evaluate to false."> … … 517 517 </tr> 518 518 <tr> 519 <td class="left">Expires: Ju ne 18, 2013</td>520 <td class="right">December 15, 2012</td>519 <td class="left">Expires: July 2, 2013</td> 520 <td class="right">December 29, 2012</td> 521 521 </tr> 522 522 </tbody> … … 545 545 in progress”. 546 546 </p> 547 <p>This Internet-Draft will expire on Ju ne 18, 2013.</p>547 <p>This Internet-Draft will expire on July 2, 2013.</p> 548 548 <h1><a id="rfc.copyrightnotice" href="#rfc.copyrightnotice">Copyright Notice</a></h1> 549 549 <p>Copyright © 2012 IETF Trust and the persons identified as the document authors. All rights reserved.</p> … … 1056 1056 <div id="rfc.iref.21"></div> 1057 1057 <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a> <a id="status.304" href="#status.304">304 Not Modified</a></h2> 1058 <p id="rfc.section.4.1.p.1">The 304status code indicates that a conditional GET request has been received and would have resulted in a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response if it were not for the fact that the condition has evaluated to false. In other words, there is no need for the server1058 <p id="rfc.section.4.1.p.1">The <dfn>304 (Not Modified)</dfn> status code indicates that a conditional GET request has been received and would have resulted in a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response if it were not for the fact that the condition has evaluated to false. In other words, there is no need for the server 1059 1059 to transfer a representation of the target resource because the request indicates that the client which made the request conditional 1060 1060 already has a valid representation; the server is therefore redirecting that client to make use of that stored representation 1061 1061 as if it were the payload of a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response. 1062 1062 </p> 1063 <p id="rfc.section.4.1.p.2">The 304 response <em class="bcp14">MUST NOT</em> contain a message-body, and thus is always terminated by the first empty line after the header fields. 1064 </p> 1065 <p id="rfc.section.4.1.p.3">A 304 response <em class="bcp14">MUST</em> include a <a href="p2-semantics.html#header.date" class="smpl">Date</a> header field (<a href="p2-semantics.html#header.date" title="Date">Section 7.1.1.2</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content">[Part2]</cite></a>) unless the origin server does not have a clock that can provide a reasonable approximation of the current time. If a <a href="p2-semantics.html#status.200" class="smpl">200 1066 (OK)</a> response to the same request would have included any of the header fields <a href="p6-cache.html#header.cache-control" class="smpl">Cache-Control</a>, <a href="p2-semantics.html#header.content-location" class="smpl">Content-Location</a>, <a href="#header.etag" class="smpl">ETag</a>, <a href="p6-cache.html#header.expires" class="smpl">Expires</a>, or <a href="p2-semantics.html#header.vary" class="smpl">Vary</a>, then those same header fields <em class="bcp14">MUST</em> be sent in a 304 response. 1063 <p id="rfc.section.4.1.p.2">A 304 response cannot contain a message-body; it is always terminated by the first empty line after the header fields.</p> 1064 <p id="rfc.section.4.1.p.3">If a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response to the same request would have included any of the header fields <a href="p6-cache.html#header.cache-control" class="smpl">Cache-Control</a>, <a href="p2-semantics.html#header.content-location" class="smpl">Content-Location</a>, <a href="#header.etag" class="smpl">ETag</a>, <a href="p6-cache.html#header.expires" class="smpl">Expires</a>, or <a href="p2-semantics.html#header.vary" class="smpl">Vary</a>, then the sender <em class="bcp14">MUST</em> generate those same header fields in a 304 response. 1067 1065 </p> 1068 1066 <p id="rfc.section.4.1.p.4">Since the goal of a 304 response is to minimize information transfer when the recipient already has one or more cached representations, 1069 the response <em class="bcp14">SHOULD NOT</em> include representation metadata other than the above listed fields unless said metadata exists for the purpose of guiding1067 a sender <em class="bcp14">SHOULD NOT</em> generate representation metadata other than the above listed fields unless said metadata exists for the purpose of guiding 1070 1068 cache updates (e.g., future HTTP extensions). 1071 1069 </p> … … 1078 1076 <div id="rfc.iref.21"></div> 1079 1077 <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a> <a id="status.412" href="#status.412">412 Precondition Failed</a></h2> 1080 <p id="rfc.section.4.2.p.1">The 412 status code indicates that one or more preconditions given in the request header fields evaluated to false when tested1081 onthe server. This response code allows the client to place preconditions on the current resource state (its current representations1078 <p id="rfc.section.4.2.p.1">The <dfn>412 (Precondition Failed)</dfn> status code indicates that one or more preconditions given in the request header fields evaluated to false when tested on 1079 the server. This response code allows the client to place preconditions on the current resource state (its current representations 1082 1080 and metadata) and thus prevent the request method from being applied if the target resource is in an unexpected state. 1083 1081 </p> … … 1317 1315 <a href="#imported.abnf" class="smpl">obs-text</a> = <obs-text, defined in <a href="#Part1" id="rfc.xref.Part1.9"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing">[Part1]</cite></a>, <a href="p1-messaging.html#field.components" title="Field value components">Section 3.2.6</a>> 1318 1316 </pre><p id="rfc.section.B.p.4">The rules below are defined in other parts:</p> 1319 <div id="rfc.figure.u.17"></div><pre class="inline"> <a href="#imported.abnf" class="smpl">HTTP-date</a> = <HTTP-date, defined in <a href="#Part2" id="rfc.xref.Part2. 5"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content">[Part2]</cite></a>, <a href="p2-semantics.html#http.date" title="Date/Time Formats">Section 7.1.1.1</a>>1317 <div id="rfc.figure.u.17"></div><pre class="inline"> <a href="#imported.abnf" class="smpl">HTTP-date</a> = <HTTP-date, defined in <a href="#Part2" id="rfc.xref.Part2.4"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content">[Part2]</cite></a>, <a href="p2-semantics.html#http.date" title="Date/Time Formats">Section 7.1.1.1</a>> 1320 1318 </pre><h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a> <a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1> 1321 1319 <div id="rfc.figure.u.18"></div> <pre class="inline"><a href="#header.etag" class="smpl">ETag</a> = entity-tag … … 1441 1439 </ul> 1442 1440 </li> 1443 <li><em>Part2</em> <a href="#rfc.xref.Part2.1">1</a>, <a href="#rfc.xref.Part2.2">2.3.3</a>, <a href="#rfc.xref.Part2.3">2.3.3</a>, <a href="# rfc.xref.Part2.4">4.1</a>, <a href="#Part2"><b>9.1</b></a>, <a href="#rfc.xref.Part2.5">B</a><ul>1441 <li><em>Part2</em> <a href="#rfc.xref.Part2.1">1</a>, <a href="#rfc.xref.Part2.2">2.3.3</a>, <a href="#rfc.xref.Part2.3">2.3.3</a>, <a href="#Part2"><b>9.1</b></a>, <a href="#rfc.xref.Part2.4">B</a><ul> 1444 1442 <li><em>Section 3.4</em> <a href="#rfc.xref.Part2.2">2.3.3</a></li> 1445 1443 <li><em>Section 5.3.4</em> <a href="#rfc.xref.Part2.3">2.3.3</a></li> 1446 <li><em>Section 7.1.1.1</em> <a href="#rfc.xref.Part2.5">B</a></li> 1447 <li><em>Section 7.1.1.2</em> <a href="#rfc.xref.Part2.4">4.1</a></li> 1444 <li><em>Section 7.1.1.1</em> <a href="#rfc.xref.Part2.4">B</a></li> 1448 1445 </ul> 1449 1446 </li>
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