Ignore:
Timestamp:
03/09/12 23:03:33 (8 years ago)
Author:
fielding@…
Message:

(editorial) move Vary to p2 because it is generated by origin servers and not limited to caching

File:
1 edited

Legend:

Unmodified
Added
Removed
  • draft-ietf-httpbis/latest/p2-semantics.xml

    r1859 r1860  
    6969  <!ENTITY header-upgrade             "<xref target='Part1' x:rel='#header.upgrade' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
    7070  <!ENTITY header-user-agent          "<xref target='header.user-agent' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
    71   <!ENTITY header-vary                "<xref target='Part6' x:rel='#header.vary' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
    7271  <!ENTITY header-via                 "<xref target='Part1' x:rel='#header.via' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
    7372  <!ENTITY header-warning             "<xref target='Part6' x:rel='#header.warning' xmlns:x='http://purl.org/net/xml2rfc/ext'/>">
     
    802801</x:note>
    803802<t>
    804    The <x:ref>Vary</x:ref> header field (&header-vary;) can be used to express
    805    the parameters the server uses to select a representation that is subject to
    806    proactive negotiation.
     803   The <x:ref>Vary</x:ref> header field (<xref target="header.vary"/>) can be
     804   used to express the parameters the server uses to select a representation
     805   that is subject to proactive negotiation.
    807806</t>
    808807</section>
     
    34523451  <ttcol>Header Field Name</ttcol><ttcol>Defined in...</ttcol>
    34533452
     3453  <c>Age</c> <c>&header-age;</c>
    34543454  <c>Date</c> <c><xref target="header.date"/></c>
    3455   <c>Age</c> <c>&header-age;</c>
    3456   <c>Vary</c> <c>&header-vary;</c>
     3455  <c>Vary</c> <c><xref target="header.vary"/></c>
    34573456</texttable>
    34583457
     
    35143513   practice, the date can be generated at any time during the message
    35153514   origination without affecting its semantic value.
     3515</t>
     3516</section>
     3517
     3518<section anchor="header.vary" title="Vary">
     3519   <iref item="Vary header field" primary="true" x:for-anchor="" />
     3520   <iref item="Header Fields" primary="true" subitem="Vary" x:for-anchor="" />
     3521   <x:anchor-alias value="Vary"/>
     3522<t>
     3523   The "Vary" header field conveys the set of header fields
     3524   that were used to select the representation.
     3525</t>
     3526<t>
     3527   Caches use this information as part of determining whether a stored
     3528   response can be used to satisfy a given request (&caching-neg-resp;).
     3529</t>
     3530<t>
     3531   In uncacheable or stale responses, the Vary field value advises the user
     3532   agent about the criteria that were used to select the representation.
     3533</t>
     3534<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="Vary"/>
     3535  <x:ref>Vary</x:ref> = "*" / 1#<x:ref>field-name</x:ref>
     3536</artwork></figure>
     3537<t>
     3538   The set of header fields named by the Vary field value is known as the
     3539   selecting header fields.
     3540</t>
     3541<t>
     3542   A server &SHOULD; include a Vary header field with any cacheable response
     3543   that is subject to proactive negotiation. Doing so allows a cache to
     3544   properly interpret future requests on that resource and informs the user
     3545   agent about the presence of negotiation on that resource. A server &MAY;
     3546   include a Vary header field with a non-cacheable response that is subject
     3547   to proactive negotiation, since this might provide the user agent with
     3548   useful information about the dimensions over which the response varies at
     3549   the time of the response.
     3550</t>
     3551<t>
     3552   A Vary field value of "*" signals that unspecified parameters not limited
     3553   to the header fields (e.g., the network address of the client), play a
     3554   role in the selection of the response representation; therefore, a cache
     3555   cannot determine whether this response is appropriate. A proxy &MUST-NOT;
     3556   generate the "*" value.
     3557</t>
     3558<t>
     3559   The field-names given are not limited to the set of standard header
     3560   fields defined by this specification. Field names are case-insensitive.
    35163561</t>
    35173562</section>
     
    46144659      <xref target="header.user-agent"/>
    46154660   </c>
     4661   <c>Vary</c>
     4662   <c>http</c>
     4663   <c>standard</c>
     4664   <c>
     4665      <xref target="header.vary"/>
     4666   </c>
    46164667</texttable>
    46174668<!--(END)-->
     
    48934944    <x:defines>Upgrade</x:defines>
    48944945    <x:defines>Via</x:defines>
     4946    <x:defines>field-name</x:defines>
    48954947  </x:source>
    48964948</reference>
     
    49735025  </front>
    49745026  <seriesInfo name="Internet-Draft" value="draft-ietf-httpbis-p6-cache-&ID-VERSION;"/>
    4975   <x:source href="p6-cache.xml" basename="p6-cache">
    4976     <x:defines>Vary</x:defines>
    4977   </x:source>
     5027  <x:source href="p6-cache.xml" basename="p6-cache"/>
    49785028</reference>
    49795029
     
    59626012<x:ref>User-Agent</x:ref> = product *( RWS ( product / comment ) )
    59636013
     6014<x:ref>Vary</x:ref> = "*" / ( *( "," OWS ) field-name *( OWS "," [ OWS field-name ]
     6015 ) )
     6016
    59646017<x:ref>absolute-URI</x:ref> = &lt;absolute-URI, defined in [Part1], Section 2.7&gt;
     6018
    59656019<x:ref>accept-ext</x:ref> = OWS ";" OWS token [ "=" word ]
    59666020<x:ref>accept-params</x:ref> = weight *accept-ext
     
    59696023
    59706024<x:ref>charset</x:ref> = token
     6025
    59716026<x:ref>codings</x:ref> = content-coding / "identity" / "*"
    59726027<x:ref>comment</x:ref> = &lt;comment, defined in [Part1], Section 3.2.4&gt;
     
    59746029
    59756030<x:ref>date1</x:ref> = day SP month SP year
     6031
    59766032<x:ref>date2</x:ref> = day "-" month "-" 2DIGIT
    59776033<x:ref>date3</x:ref> = month SP ( 2DIGIT / ( SP DIGIT ) )
     
    59946050
    59956051<x:ref>expect-name</x:ref> = token
     6052
    59966053<x:ref>expect-param</x:ref> = expect-name [ BWS "=" BWS expect-value ]
    59976054<x:ref>expect-value</x:ref> = token / quoted-string
     
    60026059
    60036060<x:ref>language-range</x:ref> = &lt;language-range, defined in [RFC4647], Section 2.1&gt;
     6061
    60046062<x:ref>language-tag</x:ref> = &lt;Language-Tag, defined in [RFC5646], Section 2.1&gt;
    60056063
    60066064<x:ref>mailbox</x:ref> = &lt;mailbox, defined in [RFC5322], Section 3.4&gt;
     6065
    60076066<x:ref>media-range</x:ref> = ( "*/*" / ( type "/*" ) / ( type "/" subtype ) ) *( OWS
    60086067 ";" OWS parameter )
     
    60266085
    60276086<x:ref>parameter</x:ref> = attribute "=" value
     6087
    60286088<x:ref>partial-URI</x:ref> = &lt;partial-URI, defined in [Part1], Section 2.7&gt;
    60296089<x:ref>product</x:ref> = token [ "/" product-version ]
     
    60316091
    60326092<x:ref>quoted-string</x:ref> = &lt;quoted-string, defined in [Part1], Section 3.2.4&gt;
     6093
    60336094<x:ref>qvalue</x:ref> = ( "0" [ "." *3DIGIT ] ) / ( "1" [ "." *3"0" ] )
    60346095
    60356096<x:ref>rfc1123-date</x:ref> = day-name "," SP date1 SP time-of-day SP GMT
     6097
    60366098<x:ref>rfc850-date</x:ref> = day-name-l "," SP date2 SP time-of-day SP GMT
    60376099
    60386100<x:ref>second</x:ref> = 2DIGIT
     6101
    60396102<x:ref>subtype</x:ref> = token
    60406103
    60416104<x:ref>time-of-day</x:ref> = hour ":" minute ":" second
     6105
    60426106<x:ref>token</x:ref> = &lt;token, defined in [Part1], Section 3.2.4&gt;
    60436107<x:ref>type</x:ref> = token
     
    60466110
    60476111<x:ref>weight</x:ref> = OWS ";" OWS "q=" qvalue
     6112
    60486113<x:ref>word</x:ref> = &lt;word, defined in [Part1], Section 3.2.4&gt;
    60496114
     
    60516116</artwork>
    60526117</figure>
    6053 </section>
     6118<figure><preamble>ABNF diagnostics:</preamble><artwork type="inline">
     6119; field-name UNDEFINED
     6120</artwork></figure></section>
    60546121<?ENDINC p2-semantics.abnf-appendix ?>
    60556122
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