Changeset 481

04/03/09 03:55:21 (13 years ago)

clean up / compact validation text.

1 edited


  • draft-ietf-httpbis/latest-roy/p6-cache.xml

    r480 r481  
    619619          <t>A "stale" response is one that either has explicit expiry information, or is allowed to
    620620            have heuristic expiry calculated, but is not fresh according to the calculations in
    621               <xref target="expiration.model" />. </t>
     621              <xref target="expiration.model" />.</t>
    622622          <t>Caches &MUST-NOT; return a stale response if it is prohibited by an explicit
    623623            in-protocol directive (e.g., by a "no-store" or "no-cache" cache directive, a
    642642      <section anchor="validation.model" title="Validation Model">
    643643        <t>When a cache has a stale response that it would like to use, it &SHOULD; first check
    644           with the origin server (or possibly an intermediate cache with a fresh response) to see if
     644          with the origin server (or possibly an intermediate cache) to see if
    645645          it is still usable. This is called "validating" or "revalidating" the stored response.</t>
    646646        <t>HTTP's conditional request mechanism, defined in &conditional;, is used to avoid
    648648          response includes one or more "cache validators", such as the field values of an ETag or
    649649          Last-Modified header field, then a validating GET request &SHOULD; be made conditional
    650           to those field values. The server checks the conditional request's validator against the
    651           current state of the requested resource and, if they match, the server responds with a 304
    652           (Not Modified) status code to indicate that the stored response can be refreshed and
    653           reused without retransmitting the response payload. If the validator does not match the
    654           current state of the requested resource, then the server returns a full response,
    655           including payload, so that the request can be satisfied and the stored response supplanted
    656           without the need for an additional network round-trip.</t>
    657         <t>See <xref target="combining.headers" /> regarding combining cached headers with those in
    658           a 304 response.</t>
     650          to those field values; a 304 (Not Modified) response status code indicates that the stored
     651          response can be updated and reused; see <xref target="combining.headers"/>.
     652        <t>If the cache receives a full response (i.e., one with payload), it is used to satisfy the
     653        request and replace the stored response.</t>
    659654        <t>If a cache receives a 5xx response while attempting to validate a response, it &MAY;
    660655          either forward this response to the requesting client, or act as if the server failed to
    661           respond. In the latter case, it &MAY; return a previously received response unless the
     656          respond. In the latter case, it &MAY; return a previously stored response unless the
    662657          stored response includes the "must-revalidate" cache directive (see <xref
    663658            target="cache-response-directive" />).</t>
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