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Re: HTTP Link Use cases

From: Phil Archer <parcher@icra.org>
Date: Tue, 25 Mar 2008 14:59:50 +0000
Message-ID: <47E91366.60705@icra.org>
To: Public MWBP <public-bpwg@w3.org>

As I believe Tuesday is CT TF day, I'll just give a little update on 
this. There is a wiki page being maintained by Jonathan Rees on this 
issue at [1]. He repeated his call for use cases over the weekend [2] to 
which I responded [3]. There's a load more on this issue over on the TAG 
list (and, confusingly, on the HTTP-WG list too) but the consensus seems 
to be emerging around Mark Nottingham's (updated) draft at [4].

The key discussion has been around the value of the rel attribute. The 
way it's heading is as Mark N sets out. The value is a URI. If a 
relative URI is given, such as 'stylesheet', then the assumption must be 
that it is relative to the IANA registry's namespace which is 

If you don't want to use an IANA rel type (and don't want to register 
it) then you give a complete URI, such as 

Such an HTTP Link Header would be semantically equivalent to an HTML 
Link tag or an RDF triple of the form

<resource> describedBy <description>

(Indeed, describedBy may well be the term used, in which case, the 
POWDER WG may well choose to use this and not rel="powder" - time will 



[1] http://esw.w3.org/topic/FindingResourceDescriptions
[2] http://lists.w3.org/Archives/Public/www-tag/2008Mar/0105.html
[3] http://lists.w3.org/Archives/Public/www-tag/2008Mar/0114.html
[4] http://tools.ietf.org/html/draft-nottingham-http-link-header-01

Jo Rabin wrote:
> Hi Phil
> Thanks for the gentle reminder of the need for action. ISSUE-238 and
> ACTION-703 both have a direct relevance to this, and both are
> essentially down to me to chase. I hadn't forgotten our call, or either
> of these actions, it's just that I have been running around like a
> headless chicken since the Seoul F2F and have only just managed to get
> my head back above water (if that is not too grotesque a mixed
> metaphor).
> There will definitely be input from BP on this, but there are definitely
> only 24 hours in each day.
> Jo
> ---
> Jo Rabin
> mTLD (http://dotmobi.mobi)
> mTLD Top Level Domain Limited is a private limited company incorporated
> and registered in the Republic of Ireland with registered number 398040
> and registered office at Arthur Cox Building, Earlsfort Terrace, Dublin
> 2.
>> -----Original Message-----
>> From: public-bpwg-request@w3.org [mailto:public-bpwg-request@w3.org]
> On
>> Behalf Of Phil Archer
>> Sent: 17 March 2008 09:53
>> To: Public MWBP
>> Subject: HTTP Link Use cases
>> Jo and I discussed this on the phone the other day so this note is
>> a) to remind him of that conversation;
>> b) alert other members of the group to the issue.
>> We have discussed the potential usefulness of the HTTP Link Header in
>> the mobile space in past meetings (I recall doing so most recently at
>> TPAC last year). The issue continues to surface and resurface on the
>> IETF/W3C HTTP group and has lead to some very recent and extensive
>> discussion. Happy Halpin kicked things off this time [1] and this lead
>> to mark Nottingham breathing new life into his draft [2]. I chimed in
>> with the POWDER use case [3]. In between these are messages from the
>> likes of Roy Fielding and Julian Reschke.
>> The bulk of the discussion centred on the need for/best approach to
>> providing an HTTP Profile header, i.e. an extensible and unambiguous
> way
>> to extend relationship types. It's not as easy as it sounds...
>> If the MWBP in general, and the CTTF in particular, wishes to support
>> the reinstatement of HTTP Link and comment on the wider discussion.
>> is the time when such an input can have most effect.
>> Cheers
>> Phil.
>> [1]
> http://lists.w3.org/Archives/Public/ietf-http-wg/2008JanMar/0444.html
>> [2]
> http://www.mnot.net/drafts/draft-nottingham-http-link-header-01.txt
>> [3]
> http://lists.w3.org/Archives/Public/ietf-http-wg/2008JanMar/0499.html
Received on Tuesday, 25 March 2008 15:00:45 UTC

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