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Metadata about the selected representation in a PUT response

From: Julian Reschke <julian.reschke@gmx.de>
Date: Wed, 31 Oct 2012 16:45:55 +0100
Message-ID: <509147B3.2030304@gmx.de>
To: Zhong Yu <zhong.j.yu@gmail.com>
CC: Martin Thomson <martin.thomson@gmail.com>, Dan Winship <dan.winship@gmail.com>, HTTP Working Group <ietf-http-wg@w3.org>
On 2012-10-31 16:30, Zhong Yu wrote:
> On Wed, Oct 31, 2012 at 2:13 AM, Julian Reschke <julian.reschke@gmx.de> wrote:
>> On 2012-10-30 21:40, Zhong Yu wrote:
>>>
>>> Got it. In the spec,
>>> http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-21#section-8.2
>>>>
>>>> Additional header fields define metadata about the selected
>>>> representation, which might differ from the representation included in the
>>>> message for responses to some state-changing methods
>>>
>>>
>>> So if the current representation has ETag=v1, and PUT sends a new
>>> representation to which the server assigns ETag=v2, the response to
>>> PUT may contain ETag of the old representation. (This was not in
>>> RFC2616)
>>> ...
>>
>>
>> Why would it contain the old ETag?
>
> According to the same section in the spec
>
>> We use the term "selected representation" to refer to the the current representation of a target resource that would have been selected in a successful response if the same request had used the method GET and excluded any conditional request header fields.
>
> In my example, the request is
>      PUT /resource HTTP/1.1
>
> If the same request had used the method GET
>      GET /resource HTTP/1.1
>
> the current representation with ETag=v1 would have been selected.
>
> Thereforev1 is the selected representation. If the response contains
> ETag header, it is a metadata about the selected representation, i.e.
> v1.
> ...

Well, that's certainly not what we *want* the spec to say.

Roy?

Best regards, Julian
Received on Wednesday, 31 October 2012 15:46:27 GMT

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