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Re: Fwd: I-D Action: draft-murchison-webdav-prefer-05.txt

From: Julian Reschke <julian.reschke@gmx.de>
Date: Thu, 19 Sep 2013 17:43:40 +0200
Message-ID: <523B1BAC.4050804@gmx.de>
To: Ken Murchison <murch@andrew.cmu.edu>
CC: WebDAV <w3c-dist-auth@w3.org>
On 2013-09-19 17:32, Ken Murchison wrote:
> On 09/19/2013 10:44 AM, Julian Reschke wrote:
>> On 2013-09-19 16:05, Ken Murchison wrote:
>>> ...
>>>>> The argument here is that we don't want the client to have to parse a
>>>>> body if the request is successful.  Do you recommend that we
>>>>> specify 204
>>>>> instead?
>>>>
>>>> The client doesn't need to parse the body, even if it's non empty.
>>>
>>> This is true, but including anything in the body defeats the purpose of
>>> return=minimal.  The 2xx response code tells the client that all
>>> instructions were performed successfully so there is no need for any
>>> other verbiage.
>>> ...
>>
>> I agree there's no need. I just wonder how strong the requirement no
>> to return anything is. I want to avoid a situation where clients blow
>> up just because they get a tiny status message.
>
> Playing devil's advocate here: If a client sends return=minimal with a
> PROPATCH or MKCOL/MKCALENDAR and can't handle the minimal response, then
> its a bad client.  If it can't handle a minimal success response is MUST
> NOT send return=minimal.  Likewise, if a server can't properly send a
> minimal response, then it MUST NOT return Preference-Applied.
>
> The more I think about this, I'm wondering why we can't specify that
> return=minimal requires an empty body upon success, or just specify that
> the server return 204.  If either a client or server can't implement it
> this way, then it is free to not use or ignore the preference.

We could, but then a 200 with text/plain "Success" is a valid HTTP 
response message, and fully self-descriptive. A client that breaks for 
it is just a broken client, no matter what it asked for.

We should resist the temptation to over-constrain things when HTTP 
already gives the right answer.

>> Just state that the response can be any suitable success message (200,
>> 201, 204), and - for 200/201 - a response payload (a) is not needed
>> and (b) does not need to be processed.
>
> I'd really like to nail this down, so there isn't a any variance in
> responses.  If we can't specify empty body, can we just go with 204?

I would avoid that. Don't profile HTTP when you don't have to.

Best regards, Julian
Received on Thursday, 19 September 2013 15:44:09 UTC

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