Changeset 1757 for draft-ietf-httpbis/latest/p4-conditional.html

Timestamp:

Jul 10, 2012, 12:15:16 PM (7 years ago)

Author:

julian.reschke@…

Message:

insert paragraph breaks for readability

File:

• draft-ietf-httpbis/latest/p4-conditional.html (modified) (4 diffs)

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

@@ -968 +968 @@
       <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a>&nbsp;<a id="header.if-match" href="#header.if-match">If-Match</a></h2>
       <p id="rfc.section.3.1.p.1">The "If-Match" header field can be used to make a request method conditional on the current existence or value of an entity-tag
-         for one or more representations of the target resource. If-Match is generally useful for resource update requests, such as
-         PUT requests, as a means for protecting against accidental overwrites when multiple clients are acting in parallel on the
-         same resource (i.e., the "lost update" problem). An If-Match field-value of "*" places the precondition on the existence of
-         any current representation for the target resource.
+         for one or more representations of the target resource.
+      </p>
+      <p id="rfc.section.3.1.p.2">If-Match is generally useful for resource update requests, such as PUT requests, as a means for protecting against accidental
+         overwrites when multiple clients are acting in parallel on the same resource (i.e., the "lost update" problem). An If-Match
+         field-value of "*" places the precondition on the existence of any current representation for the target resource.
       </p>
       <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.7"></span>  <a href="#header.if-match" class="smpl">If-Match</a> = "*" / 1#<a href="#header.etag" class="smpl">entity-tag</a>
-</pre><p id="rfc.section.3.1.p.3">If any of the entity-tags listed in the If-Match field value match (as per <a href="#entity.tag.comparison" title="Comparison">Section&nbsp;2.3.2</a>) the entity-tag of the selected representation for the target resource, or if "*" is given and any current representation
+</pre><p id="rfc.section.3.1.p.4">If any of the entity-tags listed in the If-Match field value match (as per <a href="#entity.tag.comparison" title="Comparison">Section&nbsp;2.3.2</a>) the entity-tag of the selected representation for the target resource, or if "*" is given and any current representation
          exists for the target resource, then the server <em class="bcp14">MAY</em> perform the request method as if the If-Match header field was not present.
       </p>
-      <p id="rfc.section.3.1.p.4">Origin servers <em class="bcp14">MUST NOT</em> perform the requested method if none of the entity-tags match, or if "*" is given and no current representation exists; instead
+      <p id="rfc.section.3.1.p.5">Origin servers <em class="bcp14">MUST NOT</em> perform the requested method if none of the entity-tags match, or if "*" is given and no current representation exists; instead
          they <em class="bcp14">MUST</em> respond with the <a href="#status.412" class="smpl">412 (Precondition Failed)</a> status code.
       </p>
-      <p id="rfc.section.3.1.p.5">Proxy servers using a cached response as the selected representation <em class="bcp14">MUST NOT</em> perform the requested method if none of the entity-tags match, or if "*" is given and no current representation exists; instead,
+      <p id="rfc.section.3.1.p.6">Proxy servers using a cached response as the selected representation <em class="bcp14">MUST NOT</em> perform the requested method if none of the entity-tags match, or if "*" is given and no current representation exists; instead,
          they <em class="bcp14">MUST</em> forward the request towards the origin server.
       </p>
-      <p id="rfc.section.3.1.p.6">If the request would, without the If-Match header field, result in anything other than a <a href="p2-semantics.html#status.2xx" class="smpl">2xx (Successful)</a> or <a href="#status.412" class="smpl">412 (Precondition Failed)</a> status code, then the If-Match header field <em class="bcp14">MUST</em> be ignored.
-      </p>
-      <p id="rfc.section.3.1.p.7">Examples:</p>
+      <p id="rfc.section.3.1.p.7">If the request would, without the If-Match header field, result in anything other than a <a href="p2-semantics.html#status.2xx" class="smpl">2xx (Successful)</a> or <a href="#status.412" class="smpl">412 (Precondition Failed)</a> status code, then the If-Match header field <em class="bcp14">MUST</em> be ignored.
+      </p>
+      <p id="rfc.section.3.1.p.8">Examples:</p>
       <div id="rfc.figure.u.10"></div><pre class="text">  If-Match: "xyzzy"
   If-Match: "xyzzy", "r2d2xxxx", "c3piozzzz"
   If-Match: *
-</pre><p id="rfc.section.3.1.p.9">The result of a request having both an If-Match header field and either an <a href="#header.if-none-match" class="smpl">If-None-Match</a> or an <a href="#header.if-modified-since" class="smpl">If-Modified-Since</a> header field is undefined by this specification.
+</pre><p id="rfc.section.3.1.p.10">The result of a request having both an If-Match header field and either an <a href="#header.if-none-match" class="smpl">If-None-Match</a> or an <a href="#header.if-modified-since" class="smpl">If-Modified-Since</a> header field is undefined by this specification.
       </p>
       <div id="rfc.iref.i.2"></div>
@@ -995 +996 @@
       <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a>&nbsp;<a id="header.if-none-match" href="#header.if-none-match">If-None-Match</a></h2>
       <p id="rfc.section.3.2.p.1">The "If-None-Match" header field can be used to make a request method conditional on not matching any of the current entity-tag
-         values for representations of the target resource. If-None-Match is primarily used in conditional GET requests to enable efficient
-         updates of cached information with a minimum amount of transaction overhead. A client that has one or more representations
-         previously obtained from the target resource can send If-None-Match with a list of the associated entity-tags in the hope
-         of receiving a <a href="#status.304" class="smpl">304 (Not Modified)</a> response if at least one of those representations matches the selected representation.
-      </p>
-      <p id="rfc.section.3.2.p.2">If-None-Match can also be used with a value of "*" to prevent an unsafe request method (e.g., PUT) from inadvertently modifying
+         values for representations of the target resource.
+      </p>
+      <p id="rfc.section.3.2.p.2">If-None-Match is primarily used in conditional GET requests to enable efficient updates of cached information with a minimum
+         amount of transaction overhead. A client that has one or more representations previously obtained from the target resource
+         can send If-None-Match with a list of the associated entity-tags in the hope of receiving a <a href="#status.304" class="smpl">304 (Not
+            Modified)</a> response if at least one of those representations matches the selected representation.
+      </p>
+      <p id="rfc.section.3.2.p.3">If-None-Match can also be used with a value of "*" to prevent an unsafe request method (e.g., PUT) from inadvertently modifying
          an existing representation of the target resource when the client believes that the resource does not have a current representation.
          This is a variation on the "lost update" problem that might arise if more than one client attempts to create an initial representation
@@ -1006 +1009 @@
       </p>
       <div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.8"></span>  <a href="#header.if-none-match" class="smpl">If-None-Match</a> = "*" / 1#<a href="#header.etag" class="smpl">entity-tag</a>
-</pre><p id="rfc.section.3.2.p.4">If any of the entity-tags listed in the If-None-Match field-value match (as per <a href="#entity.tag.comparison" title="Comparison">Section&nbsp;2.3.2</a>) the entity-tag of the selected representation, or if "*" is given and any current representation exists for that resource,
+</pre><p id="rfc.section.3.2.p.5">If any of the entity-tags listed in the If-None-Match field-value match (as per <a href="#entity.tag.comparison" title="Comparison">Section&nbsp;2.3.2</a>) the entity-tag of the selected representation, or if "*" is given and any current representation exists for that resource,
          then the server <em class="bcp14">MUST NOT</em> perform the requested method. Instead, if the request method was GET or HEAD, the server <em class="bcp14">SHOULD</em> respond with a <a href="#status.304" class="smpl">304 (Not Modified)</a> status code, including the cache-related header fields (particularly <a href="#header.etag" class="smpl">ETag</a>) of the selected representation that has a matching entity-tag. For all other request methods, the server <em class="bcp14">MUST</em> respond with a <a href="#status.412" class="smpl">412 (Precondition Failed)</a> status code.
       </p>
-      <p id="rfc.section.3.2.p.5">If none of the entity-tags match, then the server <em class="bcp14">MAY</em> perform the requested method as if the If-None-Match header field did not exist, but <em class="bcp14">MUST</em> also ignore any <a href="#header.if-modified-since" class="smpl">If-Modified-Since</a> header field(s) in the request. That is, if no entity-tags match, then the server <em class="bcp14">MUST NOT</em> return a <a href="#status.304" class="smpl">304 (Not Modified)</a> response.
-      </p>
-      <p id="rfc.section.3.2.p.6">If the request would, without the If-None-Match header field, result in anything other than a <a href="p2-semantics.html#status.2xx" class="smpl">2xx (Successful)</a> or <a href="#status.304" class="smpl">304 (Not Modified)</a> status code, then the If-None-Match header field <em class="bcp14">MUST</em> be ignored. (See <a href="#rules.for.when.to.use.entity.tags.and.last-modified.dates" title="Rules for When to Use Entity-tags and Last-Modified Dates">Section&nbsp;2.4</a> for a discussion of server behavior when both <a href="#header.if-modified-since" class="smpl">If-Modified-Since</a> and If-None-Match appear in the same request.)
-      </p>
-      <p id="rfc.section.3.2.p.7">Examples:</p>
+      <p id="rfc.section.3.2.p.6">If none of the entity-tags match, then the server <em class="bcp14">MAY</em> perform the requested method as if the If-None-Match header field did not exist, but <em class="bcp14">MUST</em> also ignore any <a href="#header.if-modified-since" class="smpl">If-Modified-Since</a> header field(s) in the request. That is, if no entity-tags match, then the server <em class="bcp14">MUST NOT</em> return a <a href="#status.304" class="smpl">304 (Not Modified)</a> response.
+      </p>
+      <p id="rfc.section.3.2.p.7">If the request would, without the If-None-Match header field, result in anything other than a <a href="p2-semantics.html#status.2xx" class="smpl">2xx (Successful)</a> or <a href="#status.304" class="smpl">304 (Not Modified)</a> status code, then the If-None-Match header field <em class="bcp14">MUST</em> be ignored. (See <a href="#rules.for.when.to.use.entity.tags.and.last-modified.dates" title="Rules for When to Use Entity-tags and Last-Modified Dates">Section&nbsp;2.4</a> for a discussion of server behavior when both <a href="#header.if-modified-since" class="smpl">If-Modified-Since</a> and If-None-Match appear in the same request.)
+      </p>
+      <p id="rfc.section.3.2.p.8">Examples:</p>
       <div id="rfc.figure.u.12"></div><pre class="text">  If-None-Match: "xyzzy"
   If-None-Match: W/"xyzzy"
@@ -1019 +1022 @@
   If-None-Match: W/"xyzzy", W/"r2d2xxxx", W/"c3piozzzz"
   If-None-Match: *
-</pre><p id="rfc.section.3.2.p.9">The result of a request having both an If-None-Match header field and either an <a href="#header.if-match" class="smpl">If-Match</a> or an <a href="#header.if-unmodified-since" class="smpl">If-Unmodified-Since</a> header field is undefined by this specification.
+</pre><p id="rfc.section.3.2.p.10">The result of a request having both an If-None-Match header field and either an <a href="#header.if-match" class="smpl">If-Match</a> or an <a href="#header.if-unmodified-since" class="smpl">If-Unmodified-Since</a> header field is undefined by this specification.
       </p>
       <div id="rfc.iref.i.3"></div>