Changeset 2129 for draft-ietf-httpbis/latest

Timestamp:

19/01/13 14:17:03 (10 years ago)

Author:

fielding@…

Message:

reduce requirements targeting entity-tag to facts; addresses #350

Location:

draft-ietf-httpbis/latest

Files:

• p4-conditional.html (modified) (5 diffs)
• p4-conditional.xml (modified) (4 diffs)

draft-ietf-httpbis/latest/p4-conditional.html

@@ -578 +578 @@
                      <li><a href="#rfc.section.2.3.1">2.3.1</a>&nbsp;&nbsp;&nbsp;<a href="#entity.tag.generation">Generation</a></li>
                      <li><a href="#rfc.section.2.3.2">2.3.2</a>&nbsp;&nbsp;&nbsp;<a href="#entity.tag.comparison">Comparison</a></li>
-                     <li><a href="#rfc.section.2.3.3">2.3.3</a>&nbsp;&nbsp;&nbsp;<a href="#example.entity.tag.vs.conneg">Example: Entity-tags varying on Content-Negotiated Resources</a></li>
+                     <li><a href="#rfc.section.2.3.3">2.3.3</a>&nbsp;&nbsp;&nbsp;<a href="#example.entity.tag.vs.conneg">Example: Entity-tags Varying on Content-Negotiated Resources</a></li>
                   </ul>
                </li>
@@ -666 +666 @@
          in use and imposes restrictions on when weak validators can be used as preconditions.
       </p>
-      <p id="rfc.section.2.1.p.2">A "strong validator" is a representation metadata value that is changed to a new, previously unused or guaranteed unique,
-         value whenever a change occurs to the representation data such that a change would be observable in the payload body of a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response to GET.
+      <p id="rfc.section.2.1.p.2">A "strong validator" is representation metadata that changes value whenever a change occurs to the representation data that
+         would be observable in the payload body of a <a href="p2-semantics.html#status.200" class="smpl">200 (OK)</a> response to GET.
       </p>
       <p id="rfc.section.2.1.p.3">A strong validator might change for other reasons, such as when a semantically significant part of the representation metadata
@@ -687 +687 @@
          such as might occur with content negotiation over media types that happen to share the same data format, then the origin server <em class="bcp14">SHOULD</em> incorporate additional information in the validator to distinguish those representations and avoid confusing cache behavior.
       </p>
-      <p id="rfc.section.2.1.p.6">In contrast, a "weak validator" is a representation metadata value that might not be changed for every change to the representation
-         data. This weakness might be due to limitations in how the value is calculated, such as clock resolution or an inability to
-         ensure uniqueness for all possible representations of the resource, or due to a desire by the resource owner to group representations
+      <p id="rfc.section.2.1.p.6">In contrast, a "weak validator" is representation metadata that might not change for every change to the representation data.
+         This weakness might be due to limitations in how the value is calculated, such as clock resolution or an inability to ensure
+         uniqueness for all possible representations of the resource, or due to a desire by the resource owner to group representations
          by some self-determined set of equivalency rather than unique sequences of data. An origin server <em class="bcp14">SHOULD</em> change a weak entity-tag whenever it considers prior representations to be unacceptable as a substitute for the current representation.
          In other words, a weak entity-tag ought to change whenever the origin server wants caches to invalidate old responses.
@@ -793 +793 @@
   ETag: ""
 </pre><p id="rfc.section.2.3.p.6">An entity-tag can be either a weak or strong validator, with strong being the default. If an origin server provides an entity-tag
-         for a representation and the generation of that entity-tag does not satisfy the requirements for a strong validator (<a href="#weak.and.strong.validators" title="Weak versus Strong">Section&nbsp;2.1</a>), then the origin server <em class="bcp14">MUST</em> mark the entity-tag as weak by prefixing its opaque value with "W/" (case-sensitive).
+         for a representation and the generation of that entity-tag does not satisfy all of the characteristics of a strong validator
+         (<a href="#weak.and.strong.validators" title="Weak versus Strong">Section&nbsp;2.1</a>), then the origin server <em class="bcp14">MUST</em> mark the entity-tag as weak by prefixing its opaque value with "W/" (case-sensitive).
       </p>
       <h3 id="rfc.section.2.3.1"><a href="#rfc.section.2.3.1">2.3.1</a>&nbsp;<a id="entity.tag.generation" href="#entity.tag.generation">Generation</a></h3>
@@ -860 +861 @@
          </table>
       </div>
-      <h3 id="rfc.section.2.3.3"><a href="#rfc.section.2.3.3">2.3.3</a>&nbsp;<a id="example.entity.tag.vs.conneg" href="#example.entity.tag.vs.conneg">Example: Entity-tags varying on Content-Negotiated Resources</a></h3>
+      <h3 id="rfc.section.2.3.3"><a href="#rfc.section.2.3.3">2.3.3</a>&nbsp;<a id="example.entity.tag.vs.conneg" href="#example.entity.tag.vs.conneg">Example: Entity-tags Varying on Content-Negotiated Resources</a></h3>
       <p id="rfc.section.2.3.3.p.1">Consider a resource that is subject to content negotiation (<a href="p2-semantics.html#content.negotiation" title="Content Negotiation">Section 3.4</a> of <a href="#Part2" id="rfc.xref.Part2.2"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content">[Part2]</cite></a>), and where the representations sent in response to a GET request vary based on the <a href="p2-semantics.html#header.accept-encoding" class="smpl">Accept-Encoding</a> request header field (<a href="p2-semantics.html#header.accept-encoding" title="Accept-Encoding">Section 5.3.4</a> of <a href="#Part2" id="rfc.xref.Part2.3"><cite title="Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content">[Part2]</cite></a>):
       </p>

draft-ietf-httpbis/latest/p4-conditional.xml

@@ -209 +209 @@
 </t>
 <t>
-   A "strong validator" is a representation metadata value that is
-   changed to a new, previously unused or guaranteed unique, value whenever
-   a change occurs to the representation data such that a change would be
-   observable in the payload body of a <x:ref>200 (OK)</x:ref> response to GET.
+   A "strong validator" is representation metadata that changes value whenever
+   a change occurs to the representation data that would be observable in the
+   payload body of a <x:ref>200 (OK)</x:ref> response to GET.
 </t>
 <t>   
-   A strong validator might change for other reasons, such as when a semantically
-   significant part of the representation metadata is changed (e.g.,
-   <x:ref>Content-Type</x:ref>), but it is in the best interests of the origin
-   server to only change the value when it is necessary to invalidate the
-   stored responses held by remote caches and authoring tools.  A strong
-   validator is unique across all representations of a given resource,
-   such that no two representations of that resource share the same validator
+   A strong validator might change for other reasons, such as when a
+   semantically significant part of the representation metadata is changed
+   (e.g., <x:ref>Content-Type</x:ref>), but it is in the best interests of the
+   origin server to only change the value when it is necessary to invalidate
+   the stored responses held by remote caches and authoring tools. A strong
+   validator is unique across all representations of a given resource, such
+   that no two representations of that resource share the same validator
    unless their payload body would be identical.
 </t>
@@ -250 +249 @@
 </t>
 <t>
-   In contrast, a "weak validator" is a representation metadata value that
-   might not be changed for every change to the representation data.  This
+   In contrast, a "weak validator" is representation metadata that
+   might not change for every change to the representation data.  This
    weakness might be due to limitations in how the value is calculated, such
    as clock resolution or an inability to ensure uniqueness for all possible
@@ -452 +451 @@
    strong being the default.  If an origin server provides an entity-tag
    for a representation and the generation of that entity-tag does not satisfy
-   the requirements for a strong validator
+   all of the characteristics of a strong validator
    (<xref target="weak.and.strong.validators"/>), then the origin server
    &MUST; mark the entity-tag as weak by prefixing its opaque value
@@ -535 +534 @@
 </section>
 
-<section title="Example: Entity-tags varying on Content-Negotiated Resources" anchor="example.entity.tag.vs.conneg">
+<section title="Example: Entity-tags Varying on Content-Negotiated Resources" anchor="example.entity.tag.vs.conneg">
 <t>
    Consider a resource that is subject to content negotiation