Subject: Proposal: i105 Classification for Allow header

From: Mark Nottingham <[email-masked]>
Date: Mon, 3 Mar 2008 13:07:42 +1100

<http://www3.tools.ietf.org/wg/httpbis/trac/ticket/105>

Proposal:

Change the classification of Allow to a response header, removing the  
following text;

   The Allow header field MAY be provided with a PUT request to  
recommend the methods to be supported by the new or modified resource.  
The server is not required to support these methods and SHOULD include  
an Allow header in the response giving the actual supported methods.

(or moving to an appendix and marking as deprecated behaviour)

--
Mark Nottingham     http://www.mnot.net/

---

From: Robert Siemer <[email-masked]>
Date: Mon, 3 Mar 2008 05:37:59 +0100

> an Allow header in the response giving the actual supported methods.

Removing or deprecating unused features that have no affect on 
interoperability is not on the charter.

But, yes, Allow should be a response (and request) header. Is has not 
much to do with the entity.

Greetings,
		Robert

---

From: Julian Reschke <[email-masked]>
Date: Mon, 03 Mar 2008 09:20:31 +0100

Mark Nottingham wrote:
>   The Allow header field MAY be provided with a PUT request to recommend 
> the methods to be supported by the new or modified resource. The server 
> is not required to support these methods and SHOULD include an Allow 
> header in the response giving the actual supported methods.
> 

+1, unless examples of it being used turn up.

If we remove it, I think mentioning it in the Changes section would be 
sufficient.

BR, Julian

---

From: Mark Nottingham <[email-masked]>
Date: Tue, 11 Mar 2008 15:36:37 +1100

I'm going to call this closed for now; if new information turns up, we  
can reopen it.

On 03/03/2008, at 7:20 PM, Julian Reschke wrote:

>> Change the classification of Allow to a response header, removing  
>> the following text;
>> recommend the methods to be supported by the new or modified  
>> resource. The server is not required to support these methods and  
>> SHOULD include an Allow header in the response giving the actual  
>> supported methods.
> If we remove it, I think mentioning it in the Changes section would  
> be sufficient.
>
> BR, Julian
>
>

---

From: Julian Reschke <[email-masked]>
Date: Tue, 11 Mar 2008 09:48:22 +0100

OK,

done with <http://www3.tools.ietf.org/wg/httpbis/trac/changeset/232>.

Note that this mainly affects P2, where I added the statement below to 
the Changes appendix:

"Reclassify Allow header as response header, removing the option to 
specify it in a PUT request. (Section 10.1)"

Also note that with this change, we got rid of another ABNF dependency 
from P3 to P2.

BR, Julian

---

From: Robert Siemer <[email-masked]>
Date: Tue, 11 Mar 2008 12:23:21 +0100

> I'm going to call this closed for now; if new information turns up, we  

I haven't seen a response to my comment: why is it important or valid
under the current charter to remove the possibility to use "Allow" in
a request?

Robert

---

From: Julian Reschke <[email-masked]>
Date: Tue, 11 Mar 2008 12:37:45 +0100

> under the current charter to remove the possibility to use "Allow" in

Doesn't that fall under

"* Remove or deprecate those features that are not widely implemented
and also unduly affect interoperability"

?

BR, Julian

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From: "Brian Smith" <[email-masked]>
Date: Tue, 11 Mar 2008 04:55:46 -0700

Robert Siemer wrote:
> I haven't seen a response to my comment: why is it important 
> or valid under the current charter to remove the possibility 
> to use "Allow" in a request?

The change does not forbid the use of "Allow" in a request. It just
makes its semantics undefined for requests. That makes sense, because in
practice people are not following the RFC 2616 semantics for that case.

This is also a good idea, because it provides an opportunity for another
RFC to define an "Allow" mechanism that actually makes sense. There is
no way to make "Allow" (in a request or a response) generally useful
without a corresponding "Disallow" header, and such an addition is out
of scope according to the charter.

- Brian

---

From: Robert Siemer <[email-masked]>
Date: Sun, 16 Mar 2008 11:56:20 +0100

> practice people are not following the RFC 2616 semantics for that case.

Okay, that sounds reasonable to me.

Robert