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Re: i24: Requiring Allow in 405 responses

From: Mark Nottingham <mnot@mnot.net>
Date: Tue, 5 Feb 2008 08:51:24 -0800
Cc: Mark Baker <distobj@acm.org>, HTTP Working Group <ietf-http-wg@w3.org>, "Roy T. Fielding" <fielding@gbiv.com>
Message-Id: <37CEFE1E-395D-49A9-9B97-1A930B9FA5FC@mnot.net>
To: Henrik Nordström <henrik@henriknordstrom.net>

Fair enough. Henrik, any thoughts about SHOULD vs MAY? Roy and Mark  
both expressed a preference for MAY.


On 05/02/2008, at 7:35 AM, Henrik Nordström wrote:

> I meant replacing MUST by SHOULD, making the use of Allow in 405
> responses a SHOULD level requirement.
>
> This is a requirement that is in some cases impractical for servers to
> implement properly. And it's also a case where it's most likely better
> the sever doesn't say anything at all if it doesn't know than to try  
> to
> guess.. If it doesn't know let the client guess if it want.
>
> But on the other hand a 405 without Allow is pretty much equivalent  
> to a
> 403. So an alternative approach would be to add a note that if the
> server can not provide a reliable list of allowed methods then 403
> should be returned instead of 405, reserving 405 to be used only when
> the server knows within rasonable doubt what methods it accepts on the
> resource. And this is probably a better way to address the problem.
>
> I do not think relaxing the meaning of Allow is a good idea. If  
> Allow is
> given then the client SHOULD assume it's the truth. Changing this  
> would
> render Allow as such pretty useless.
>
> It's the same for Allow headers in response to GET btw. If the server
> doesn't really know then there SHOULD NOT be an Allow header in the
> response.
>
> Regards
> Henrik
>
>
>
> tis 2008-02-05 klockan 06:39 -0800 skrev Mark Nottingham:
>> Are you saying that s/MUST/SHOULD/ is adequate, or agreeing that
>> splitting it into two requirements, making the second a SHOULD, is
>> necessary?
>>
>>
>> On 05/02/2008, at 4:47 AM, Henrik Nordström wrote:
>>
>>>
>>> mån 2008-02-04 klockan 23:08 -0800 skrev Mark Nottingham:
>>>> My thinking was that it may be necessary to preserve the MUST on  
>>>> the
>>>> presence of the header (in case any software had been written to
>>>> depend upon its presence), but to loosen the implied requirement  
>>>> that
>>>> the list of headers be complete.
>>>
>>> SHOULD is more than sufficuent for a such requirement level.
>>>
>>> Regards
>>> Henrik
>>
>>
>> --
>> Mark Nottingham     http://www.mnot.net/
>>
>>


--
Mark Nottingham     http://www.mnot.net/
Received on Tuesday, 5 February 2008 16:51:43 GMT

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