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Re: WGLC #353: Multiple Values in Cache-Control headers

From: Amos Jeffries <squid3@treenet.co.nz>
Date: Sat, 09 Jun 2012 00:10:43 +1200
Message-ID: <4FD1EBC3.9070007@treenet.co.nz>
To: ietf-http-wg@w3.org
On 8/06/2012 10:15 p.m., Julian Reschke wrote:
> On 2012-06-08 12:06, Mark Nottingham wrote:
>>
>> On 08/06/2012, at 7:57 PM, Julian Reschke wrote:
>>
>>> On 2012-06-08 09:30, Mark Nottingham wrote:
>>>> Revised proposal, based upon discussion:
>>>>
>>>>> Add a note to 
>>>>> <https://svn.tools.ietf.org/svn/wg/httpbis/draft-ietf-httpbis/latest/p6-cache.html#calculating.freshness.lifetime>:
>>>>>
>>>>> """
>>>>> When there is more than one value present for a given directive 
>>>>> (e.g., two Expires headers, multiple Cache-Control: max-age 
>>>>> directives), it is considered invalid. Caches SHOULD consider 
>>>>> responses that have invalid freshness information to be stale.
>>>>> """
>>>>
>>>>
>>>> Any further comments? Otherwise we'll close and incorporate.
>>>> ...
>>>
>>> Would it make sense to have generic text in the definition of 
>>> Cache-Control about this?
>>
>> Don't think so, because...
>>
>>> Does the "must have a single value" rule apply to all directives?
>>
>> No; I've seen examples that use multiple values (can't remember what 
>> ATM)
>
> If that is the case, we probably need to spend some more time on 
> clarifying this, as this different from similar header fields.
>
>>> Can the definition of error recovery diverge per directive?
>>
>> I imagine so.
>
> Which makes it sound as if we should define it for all directives 
> defined in this spec (as bad as this sounds)...
>
> Best regards, Julian
>

Or with a blanket to cover the generic "safe" erro rhandlign of dropping 
something. ie I would imagine duplicate identical controls it would be 
harmless to drop duplicates before interpreting the controls.

And a specific mention of anythign special for those directives with 
parameter values. Which face a more difficult time resolving multiples 
and non-duplicate values.

AYJ
Received on Friday, 8 June 2012 12:11:24 GMT

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