Changeset 1715 for draft-ietf-httpbis/latest/p6-cache.html
- Timestamp:
- 04/07/12 19:54:55 (10 years ago)
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draft-ietf-httpbis/latest/p6-cache.html
r1713 r1715 832 832 </p> 833 833 <p id="rfc.section.2.p.2">Each <dfn>cache entry</dfn> consists of a cache key and one or more HTTP responses corresponding to prior requests that used the same key. The most common 834 form of cache entry is a successful result of a retrieval request: i.e., a 200 (OK) response containing a representation of835 the resource identified by the request target. However, it is also possible to cachenegative results (e.g., <a href="p2-semantics.html#status.404" class="smpl">404 (Not Found)</a>, incomplete results (e.g., <a href="p5-range.html#status.206" class="smpl">206 (Partial Content)</a>), and responses to safe methods other than GET if the method's definition allows such caching and defines something suitable834 form of cache entry is a successful result of a retrieval request: i.e., a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response containing a representation of the resource identified by the request target. However, it is also possible to cache 835 negative results (e.g., <a href="p2-semantics.html#status.404" class="smpl">404 (Not Found)</a>, incomplete results (e.g., <a href="p5-range.html#status.206" class="smpl">206 (Partial Content)</a>), and responses to safe methods other than GET if the method's definition allows such caching and defines something suitable 836 836 for use as a cache key. 837 837 </p> … … 876 876 time, as such responses are not usually useful to store. However, caches are not prohibited from storing such responses. 877 877 </p> 878 <p id="rfc.section.2.1.p.5">A response message is considered complete when all of the octets indicated by the message framing (<a href="#Part1" id="rfc.xref.Part1.11"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) are received prior to the connection being closed. If the request is GET, the response status is 200 (OK), and the entire 879 response header block has been received, a cache <em class="bcp14">MAY</em> store an incomplete response message body if the cache entry is recorded as incomplete. Likewise, a <a href="p5-range.html#status.206" class="smpl">206 (Partial Content)</a> response <em class="bcp14">MAY</em> be stored as if it were an incomplete 200 (OK) cache entry. However, a cache <em class="bcp14">MUST NOT</em> store incomplete or partial content responses if it does not support the Range and Content-Range header fields or if it does 878 <p id="rfc.section.2.1.p.5">A response message is considered complete when all of the octets indicated by the message framing (<a href="#Part1" id="rfc.xref.Part1.11"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>) are received prior to the connection being closed. If the request is GET, the response status is <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a>, and the entire response header block has been received, a cache <em class="bcp14">MAY</em> store an incomplete response message body if the cache entry is recorded as incomplete. Likewise, a <a href="p5-range.html#status.206" class="smpl">206 (Partial Content)</a> response <em class="bcp14">MAY</em> be stored as if it were an incomplete <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> cache entry. However, a cache <em class="bcp14">MUST NOT</em> store incomplete or partial content responses if it does not support the Range and Content-Range header fields or if it does 880 879 not understand the range units used in those fields. 881 880 </p> … … 1095 1094 </ul> 1096 1095 <h3 id="rfc.section.2.4.1"><a href="#rfc.section.2.4.1">2.4.1</a> <a id="freshening.responses" href="#freshening.responses">Freshening Responses with 304 Not Modified</a></h3> 1097 <p id="rfc.section.2.4.1.p.1">When a cache receives a <a href="p4-conditional.html#status.304" class="smpl">304 (Not Modified)</a> response and already has one or more stored 200 (OK) responses for the same cache key, the cache needs to identify which of 1098 the stored responses are updated by this new response and then update the stored response(s) with the new information provided 1099 in the 304 response. 1096 <p id="rfc.section.2.4.1.p.1">When a cache receives a <a href="p4-conditional.html#status.304" class="smpl">304 (Not Modified)</a> response and already has one or more stored <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> responses for the same cache key, the cache needs to identify which of the stored responses are updated by this new response 1097 and then update the stored response(s) with the new information provided in the 304 response. 1100 1098 </p> 1101 1099 <ul>
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