03/03/10 09:19:25 (12 years ago)

Simplify discussion of history lists (see #197)

1 edited


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

    r764 r766  
    1547   History mechanisms and caches are different. In particular history mechanisms
    1548   &SHOULD-NOT; try to show a correct view of the current state of a resource. Rather, a
    1549   history mechanism is meant to show exactly what the user saw at the time when the resource
    1550   was retrieved.
    1551 </t>
    1552 <t>
    1553   By default, an expiration time does not apply to history mechanisms. If the entity is still
    1554   in storage, a history mechanism &SHOULD; display it even if the entity has expired,
    1555   unless the user has specifically configured the agent to refresh expired history documents.
    1556 </t>
    1557 <t>
    1558   This is not to be construed to prohibit the history mechanism from telling the user that a
    1559   view might be stale.
    1560 </t>
    1561 <x:note>
     1547  The freshness model (<xref target="expiration.model"/>) does not necessarily apply to history mechanisms. I.e.,
     1548  a history mechanism can display a previous representation even if it has expired.
    15621550  <t>
    1563     <x:h>Note:</x:h> If history list mechanisms unnecessarily prevent users from viewing
    1564     stale resources, this will tend to force service authors to avoid using HTTP expiration
    1565     controls and cache controls when they would otherwise like to. Service authors may
    1566     consider it important that users not be presented with error messages or warning
    1567     messages when they use navigation controls (such as BACK) to view previously fetched
    1568     resources. Even though sometimes such resources ought not be cached, or ought to expire
    1569     quickly, user interface considerations may force service authors to resort to other
    1570     means of preventing caching (e.g., "once-only" URLs) in order not to suffer the effects
    1571     of improperly functioning history mechanisms.
     1551  This does not prohibit the history mechanism from telling the user that a
     1552  view might be stale, or from honoring cache directives (e.g., Cache-Control: no-store).
    15721553  </t>
    1573 </x:note>
    23442324<section anchor="changes.since.08" title="Since draft-ietf-httpbis-p6-cache-08">
     2326  Closed issues:
     2327  <list style="symbols">
     2328    <t>
     2329      <eref target="http://tools.ietf.org/wg/httpbis/trac/ticket/197" />:
     2330      "Effect of CC directives on history lists"
     2331    </t>
     2332  </list>
    23462335  Affected issues:
    23472336  <list style="symbols">
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