Re: #486: Requiring proxies to process warn-date

Alex Rousskov <rousskov@measurement-factory.com> Mon, 20 May 2013 16:16 UTC

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Date: Mon, 20 May 2013 10:14:32 -0600
From: Alex Rousskov <rousskov@measurement-factory.com>
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Subject: Re: #486: Requiring proxies to process warn-date
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On 05/19/2013 07:36 PM, Mark Nottingham wrote:
> On 17/05/2013, at 11:40 AM, Mark Nottingham <mnot@mnot.net> wrote:
> 
>>>> and the second to be "If a recipient receives...", also removing
>>>> "forwarding" later down.
>>>
>>> This would not be sufficient because "using" may be interpreted to
>>> include "forwarding". How about this:
>>>
>>> "A response sender MUST NOT generate warning-value with a warn-date
>>> different from the Date value in the response. A cache MUST NOT send a
>>> warning-value with a warn-date different from the Date value in the
>>> from-cache response. A recipient MUST ignore a warning-value with a
>>> warn-date different from the Date value in the response."
>>>
>>> Would that cover all important cases without being too restrictive (like
>>> requiring the cache not to store something when there is no harm in
>>> storing, only in serving from the cache)?

>> I think so, although we should remove the first 'response'.

> Looking at this again:

>> A cache MUST NOT send a warning-value with a warn-date different from the Date value in the from-cache response.


> This has the effect of requiring caches to check warning-values in
> all cached responses; do we still want to require that?


Good question. I do not know what the use cases behind the original
MUSTs were, and whether new use cases appeared since then, so I cannot
answer this question. If there is consensus that policing Warnings by
intermediaries (including caches) is not needed, then yes, we can remove
the entire MUST NOT.


Cheers,

Alex.