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

From: Mark Nottingham <mnot@mnot.net>
Date: Wed, 4 May 2011 20:30:33 +1000
Cc: HTTP Working Group <ietf-http-wg@w3.org>
Message-Id: <79ECC5BD-77F2-4C36-BEA7-F0F9F1652058@mnot.net>
To: "Poul-Henning Kamp" <phk@phk.freebsd.dk>

On 04/05/2011, at 8:27 PM, Poul-Henning Kamp wrote:

> In message <8709120E-0FE0-46CB-8A47-06AAB3B25DB9@mnot.net>, Mark Nottingham wri
> tes:
> 
>> A couple of things come to mind.
>> 
>> In requests, Pragma: no-cache is defined to be equivalent to CC: 
>> no-cache. I don't think we can change that now, as most implementations 
>> that I'm aware of honour that requirement, and more importantly, clients 
>> will have a reasonable expectation that this will continue.  A gateway 
>> cache can choose to ignore request directives, because it has implicit 
>> permission from the origin, of course.
> 
> But we can clarify that if there _also_ is a C-C, then Pragma is
> ignored.

Is your use case that you want to be able to send requests that CC-unaware HTTP/1.0 caches will pass through, and yet allow them to be pulled from cache by a CC-aware implementation?

> 
>> Does that cover the cases you're concerned about, or are you arguing 
>> that CC: max-age (etc.) in requests overrides Pragma: no-cache?
> 
> I am arguing that the most expressive and well defined header trumps
> if both are present.
> 
> If there is only Prama, follow it.  If there is only C-C, follow it.
> 
> If both are there, ignore Pragma.
> 
> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk@FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe    
> Never attribute to malice what can adequately be explained by incompetence.

--
Mark Nottingham   http://www.mnot.net/
Received on Wednesday, 4 May 2011 10:31:00 GMT

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