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Re: A new HTTP response code say 209

From: Mark Nottingham <mnot@mnot.net>
Date: Fri, 20 Dec 2013 11:42:46 +1100
Cc: TAG List <www-tag@w3.org>, Arnaud Hors <lehors@us.ibm.com>, Eric Prud'hommeaux <eric@w3.org>, Yves Lafon <ylafon@w3.org>, Philippe Le Hégaret <plh@w3.org>, Peter Linss <peter.linss@hp.com>, "Appelquist Daniel (UK)" <Daniel.Appelquist@telefonica.com>
Message-Id: <041A7DEC-9C86-45BA-B168-1C3D6786F470@mnot.net>
To: Tim Berners-Lee <timbl@w3.org>
Hi Tim,


On 20 Dec 2013, at 3:55 am, Tim Berners-Lee <timbl@w3.org> wrote:

> 
> 
> We need a new 20X status code (we refer to it as 209, though that can be regarded as a placeholder) to allow information relating to and useful but different from the original thing.
> 
> 209 could be deemed to be definitely equivalent  equivalent to 303 "see also" to another URI which gives 200.  The Location: y   header from the 303 would be the same as the one used in the 209 to identify the URI of the meta resource.
> 
> The fact that existing LD systems use 303 and LDP systems are thinking of it is a serious architectural problem as the extra round trips.
> 
> The payload is machine readable in each case I am interested in.
> 
> Example uses:
> 
> - You asked for massive data, I give you instructions for doing a query for a part of it

Couldn't you distinguish that using the media type of the response?

> - You asked for a large thing, this is the first page of it.  See Proposal [1]

That seems like it's buried in the semantics of the response media type (as Atom does).

> - You asked for some thing with URI u, I give you a document about it which has a different URI. Classic linked data use case see eg [2]

As Julian says, 303.

In all of these, I think the central question is "what truly generic semantics, independent of the media type, need to be surfaced, and to whom?" 

The latter part of the question is the meat, I think. In most cases, status codes are added because software doesn't want to touch the body, and the distinction is so important / fundamental that merely a new header won't do the trick. 


> Possible process paths:
> 
> - Just define 209 in the spec, as an unauthorized extension of HTTP.  People do this with headers and HTML tags all the time.  Do this with IESG blessing.   This may not be deemed an appropriate process with in the IETF which has change control.
> 
> - Start an IETF effort to define 209 from the ground up, ASAP.  Problems: the LDP working group's lack of confidence that the process would be timely and would not be waylaid by people who did not have/understand the needs of the linked data community.
> 
> - Reserve the 209 code with a an internet draft -- and then code it into current code, then other of the 
> 
> - Etc ...  many other combinations

Please have a look at:
  http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-25#section-8.2.2




> 
> Can we discuss this at the next call?
> Sorry about the short notice.
> 
> Timbl
> 
> Tim
> 
> [1] http://www.w3.org/2012/ldp/wiki/Meetings:Telecon2013.11.04#Proposals_regarding_Paging_.26_209_vs_200
> 
> [2] http://linkeddatabook.com/editions/1.0/#htoc12
> 
> 
> 
> 
> 
> 

--
Mark Nottingham   http://www.mnot.net/
Received on Friday, 20 December 2013 00:43:22 UTC

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