Changeset 1735 for draft-ietf-httpbis/latest/p6-cache.html
- Timestamp:
- 06/07/12 14:48:51 (10 years ago)
- File:
-
- 1 edited
Legend:
- Unmodified
- Added
- Removed
-
draft-ietf-httpbis/latest/p6-cache.html
r1734 r1735 965 965 <h4 id="rfc.section.2.3.1.1"><a href="#rfc.section.2.3.1.1">2.3.1.1</a> <a id="heuristic.freshness" href="#heuristic.freshness">Calculating Heuristic Freshness</a></h4> 966 966 <p id="rfc.section.2.3.1.1.p.1">If no explicit expiration time is present in a stored response that has a status code whose definition allows heuristic freshness 967 to be used (including the following in <a href="p2-semantics.html#status.codes" title="Status Codes">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics, Payload and Content Negotiation">[Part2]</cite></a>: 200, 203, <a href="p5-range.html#status.206" class="smpl">206</a>, 300, 301 and 410), a cache <em class="bcp14">MAY</em> calculate a heuristic expiration time. A cache <em class="bcp14">MUST NOT</em> use heuristics to determine freshness for responses with status codes that do not explicitly allow it. 967 to be used (including the following in <a href="p2-semantics.html#status.codes" title="Status Codes">Section 4</a> of <a href="#Part2" id="rfc.xref.Part2.4"><cite title="HTTP/1.1, part 2: Message Semantics, Payload and Content Negotiation">[Part2]</cite></a>: <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a>, <a href="p2-semantics.html#status.203" class="smpl">203 968 (Non-Authoritative Information)</a>, <a href="p5-range.html#status.206" class="smpl">206 (Partial Content)</a>, <a href="p2-semantics.html#status.300" class="smpl">300 (Multiple Choices)</a>, <a href="p2-semantics.html#status.301" class="smpl">301 (Moved Permanently)</a> and <a href="p2-semantics.html#status.410" class="smpl">410 (Gone)</a>), a cache <em class="bcp14">MAY</em> calculate a heuristic expiration time. A cache <em class="bcp14">MUST NOT</em> use heuristics to determine freshness for responses with status codes that do not explicitly allow it. 968 969 </p> 969 970 <p id="rfc.section.2.3.1.1.p.2">When a heuristic is used to calculate freshness lifetime, a cache <em class="bcp14">SHOULD</em> attach a Warning header field with a 113 warn-code to the response if its current_age is more than 24 hours and such a warning … … 1092 1093 request is suitable. Instead, the cache can use the full response to satisfy the request and <em class="bcp14">MAY</em> replace the stored response(s). 1093 1094 </li> 1094 <li>However, if a cache receives a 5xx response while attempting to validate a response, it can either forward this response to 1095 the requesting client, or act as if the server failed to respond. In the latter case, it can return a previously stored response 1096 (see <a href="#serving.stale.responses" title="Serving Stale Responses">Section 2.3.3</a>). 1095 <li>However, if a cache receives a <a href="p2-semantics.html#status.5xx" class="smpl">5xx (Server Error)</a> response while attempting to validate a response, it can either forward this response to the requesting client, or act as 1096 if the server failed to respond. In the latter case, it can return a previously stored response (see <a href="#serving.stale.responses" title="Serving Stale Responses">Section 2.3.3</a>). 1097 1097 </li> 1098 1098 </ul> … … 1152 1152 <p id="rfc.section.2.6.p.4">A cache <em class="bcp14">MUST</em> invalidate the effective request URI (<a href="p1-messaging.html#effective.request.uri" title="Effective Request URI">Section 5.5</a> of <a href="#Part1" id="rfc.xref.Part1.15"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) when it receives a non-error response to a request with a method whose safety is unknown. 1153 1153 </p> 1154 <p id="rfc.section.2.6.p.5">Here, a "non-error response" is one with a <a href="p2-semantics.html#status.2xx" class="smpl">2xx </a> or <a href="p2-semantics.html#status.3xx" class="smpl">3xx</a> status code. "Invalidate" means that the cache will either remove all stored responses related to the effective request URI,1154 <p id="rfc.section.2.6.p.5">Here, a "non-error response" is one with a <a href="p2-semantics.html#status.2xx" class="smpl">2xx (Successful)</a> or <a href="p2-semantics.html#status.3xx" class="smpl">3xx (Redirection)</a> status code. "Invalidate" means that the cache will either remove all stored responses related to the effective request URI, 1155 1155 or will mark these as "invalid" and in need of a mandatory validation before they can be returned in response to a subsequent 1156 1156 request.
Note: See TracChangeset
for help on using the changeset viewer.