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#290 [was: SHOULD-level requirements in p6-caching]

From: Mark Nottingham <mnot@mnot.net>
Date: Wed, 4 May 2011 12:37:14 +1000
Cc: HTTP Working Group <ietf-http-wg@w3.org>
Message-Id: <E18FC49C-0865-4534-8A14-C30BA8D40295@mnot.net>
To: Poul-Henning Kamp <phk@phk.freebsd.dk>

On 07/04/2011, at 7:35 PM, Poul-Henning Kamp wrote:
>> In 3.3,
>>>   A server SHOULD NOT send Expires dates more than one year in the
>>>   future.
>> Prose.
> Why this policy restriction ?
> Remove entirely ?

Now <http://trac.tools.ietf.org/wg/httpbis/trac/ticket/290>.

>> In 3.4,
>>>   When the no-cache directive is present in a request message, a cache
>>>   SHOULD forward the request toward the origin server even if it has a
>>>   stored copy of what is being requested.
>> Prose.
> Have you discussed the future of "Pragma:" before ?


>    This mechanism is deprecated; no new Pragma directives will be
>    defined in HTTP.

> I would like to see the text say that if there is a "Cache-Control:"
> header "Pragma:" MUST be ignored, to resolve the possible conflicts
> between them.

We already have:

> A cache SHOULD treat "Pragma: no-cache" as if the client had sent
>    "Cache-Control: no-cache".

so that makes them equivalent. 

Combined with the rules in sections 2.1 and 2.2, that *should* clarify correct behaviour when they occur together, I think.

E.g., if something has both max-age and no-cache in the response, it might be stored, but won't be reused, because it violates the fourth bullet in section 2.2.


Mark Nottingham   http://www.mnot.net/
Received on Wednesday, 4 May 2011 02:37:41 UTC

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