Ignore:
Timestamp:
19/01/14 09:51:24 (6 years ago)
Author:
fielding@…
Message:

(editorial) remove usage of We; move definition of transforming proxy into the only section that uses it, removing the need for non-transforming proxy to be defined; clean up redundant paragraphs in description of cache-control extensions; see #531

File:
1 edited

Legend:

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

    r2554 r2563  
    251251   (&semantics;) while eliminating the transfer of information already held
    252252   in the cache.  Although caching is an entirely &OPTIONAL; feature of HTTP,
    253    we assume that reusing the cached response is desirable and that such
     253   it can be assumed that reusing a cached response is desirable and that such
    254254   reuse is the default behavior when no requirement or local
    255255   configuration prevents it.  Therefore, HTTP cache requirements are focused
     
    15571557   The Cache-Control header field can be extended through the use of one or
    15581558   more cache-extension tokens, each with an optional value.
     1559   A cache &MUST; ignore unrecognized cache directives.
    15591560</t>
    15601561<t>
    15611562   Informational extensions (those that do not require a change in cache
    15621563   behavior) can be added without changing the semantics of other directives.
     1564</t>
     1565<t>   
    15631566   Behavioral extensions are designed to work by acting as modifiers to the
    15641567   existing base of cache directives.
    1565 </t>
    1566 <t>   
    1567    Both the new directive and the standard directive are supplied, such that
     1568   Both the new directive and the old directive are supplied, such that
    15681569   applications that do not understand the new directive will default to the
    1569    behavior specified by the standard directive, and those that understand the
     1570   behavior specified by the old directive, and those that understand the
    15701571   new directive will recognize it as modifying the requirements associated
    1571    with the standard directive. In this way, extensions to the cache-control
    1572    directives can be made without requiring changes to the base protocol.
    1573 </t>
    1574 <t>
    1575    This extension mechanism depends on an HTTP cache obeying all of the
    1576    cache-control directives defined for its native HTTP-version, obeying
    1577    certain extensions, and ignoring all directives that it does not
    1578    understand.
     1572   with the old directive. In this way, extensions to the existing
     1573   cache-control directives can be made without breaking deployed caches.
    15791574</t>
    15801575<t>
    15811576   For example, consider a hypothetical new response directive called
    1582    "community" that acts as a modifier to the private directive. We define
    1583    this new directive to mean that, in addition to any private cache, any
    1584    cache that is shared only by members of the community named within its
    1585    value is allowed to cache the response. An origin server wishing to allow
    1586    the UCI community to use an otherwise private response in their shared
    1587    cache(s) could do so by including
     1577   "community" that acts as a modifier to the private directive: in addition
     1578   to private caches, any cache that is shared only by members of the named
     1579   community is allowed to cache the response. An origin server wishing to
     1580   allow the UCI community to use an otherwise private response in their
     1581   shared cache(s) could do so by including
    15881582</t>
    15891583<figure><artwork type="example">
     
    15911585</artwork></figure>
    15921586<t>
    1593    A cache seeing this header field will act correctly even if the cache does
    1594    not understand the community cache-extension, since it will also see and
    1595    understand the private directive and thus default to the safe behavior.
    1596 </t>
    1597 <t>
    1598    A cache &MUST; ignore unrecognized cache directives; it is assumed that any
    1599    cache directive likely to be unrecognized by an HTTP/1.1 cache will be
    1600    combined with standard directives (or the response's default cacheability)
    1601    such that the cache behavior will remain minimally correct even if the
    1602    cache does not understand the extension(s).
     1587   A cache that recognizes such a community cache-extension could broaden its
     1588   behavior in accordance with that extension.  A cache that does not
     1589   recognize the community cache-extension would ignore it and adhere to the
     1590   private directive.
    16031591</t>
    16041592</section>
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