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Re: 304 and Age

From: Amos Jeffries <squid3@treenet.co.nz>
Date: Tue, 09 Oct 2012 13:01:53 +1300
To: <ietf-http-wg@w3.org>
Message-ID: <1be4d067fa531e5406708654cdf894ff@treenet.co.nz>
On 09.10.2012 03:04, Thomas Fossati wrote:
> Hi all,
>
> maybe a dumb one, but I couldn't find any decisive anchor for the
> following question: suppose my cache receives a conditional GET for a
> resource for which it has a fresh representation, should Age be sent
> back to the requester in a 304 ?
>
> The two points in the current spec that got me confused are:
>
> - p6, Section 4: "When a stored response is used to satisfy a request
> without validation, a cache MUST include a single Age header field in
> the response with a value equal to the stored response's 
> current_age."
>
> - p4, Section 4.1 after the paragraph listing the mandatory headers
> for 304 (which do not include Age): "Since the goal of a 304 response
> is to minimize information transfer when the recipient already has 
> one
> or more cached representations, the response should not include
> representation metadata other than the above listed fields unless 
> said
> metadata exists for the purpose of guiding cache updates (e.g., 
> future
> HTTP extensions)."
>
> TIA, Thomas.


IMO, the Age header is not useful in this case. Since the requestor 
already appears to have a copy of the representation, thus already has 
or can calculate its Age. If the requestor does not already have a coy 
(was checking for existence etc) then it does not need to know Age, but 
only existence and future lifetime - which are included via the other 
304 headers.

AYJ
Received on Tuesday, 9 October 2012 00:02:22 GMT

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