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Re: HTTP Link, rel="powder" cf. rel="describedby"

From: Phil Archer <parcher@fosi.org>
Date: Fri, 01 Aug 2008 09:57:47 +0100
Message-ID: <4892D00B.9010205@fosi.org>
To: "Scheppe, Kai-Dietrich" <k.scheppe@telekom.de>
CC: Public POWDER <public-powderwg@w3.org>

Scheppe, Kai-Dietrich wrote:
> Hi,
> So what is your thought on what the rel type could be?  Rel="meta" seems
> intuitiv, but is not regsitered.

That's a whole other can of worms - I've just written to a bunch of W3C 
folk about how a common view of registering @rel types should be done.

> Is there such a thing as rel="description" or something similar?

No - but 'describedby' is in our POWDER-s vocab and, I think the GRDDL 
folk would like it too.


>> -----Original Message-----
>> From: public-powderwg-request@w3.org 
>> [mailto:public-powderwg-request@w3.org] On Behalf Of Phil Archer
>> Sent: Friday, August 01, 2008 10:21 AM
>> To: Public POWDER
>> Subject: HTTP Link, rel="powder" cf. rel="describedby"
>> I had a (very good) meeting with Mark Nottingham yesterday. 
>> He's Yahoo's point man at the IETF and the person behind the 
>> HTTP Link Header internet draft to which our DR doc refers [1].
>> He seems happy that there is a good deal of consensus around 
>> most of the important issues that draft raises. The area 
>> where there is currently less consensus is how various 
>> relationship types should be registered and maintained. This 
>> goes way beyond POWDER in terms of scope but it clearly 
>> affects us since our docs talk about using rel="powder." 
>> We've followed the current recommendations by using a profile 
>> document.
>> Bottom line - with a bit of political negotiation - Mark 
>> believes that HTTP link will be able to progress along the 
>> route to RFC within the time line we need.
>> But... whilst our use of HTTP Link is right in Mark's view, 
>> the registration of rel="powder" probably isn't. Section 4.2 
>> [2] of the draft says:
>> "A Link relation is a way of indicating the semantics of a 
>> link.  Link relations are not format-specific, and MUST NOT 
>> specify a particular format or media type that they are to be 
>> used with."
>> I was concerned about this since rel="powder" /does/ indicate 
>> a particular format (i.e. POWDER). I raised this on the HTTP 
>> list and Jonathan Rees replied [3] that he thought this 
>> referred to the origin of the link, not its target. Mark said 
>> no - actually the intention is that /neither/ end of the link 
>> should be format-specific - that's the job of the MIME type.
>> I said that we were wary of trying to register a new MIME 
>> type - after all, POWDER is either XML or RDF/OWL (semantic extension
>> notwithstanding) and that HTML Profile meant we didn't /need/ 
>> to register either rel="powder" or a new MIME type. Well... 
>> that's true but we are talking about registering the @rel 
>> type so that argument rather loses potency!
>> Mark pointed me to a doc [4] that is an entry point for a 
>> description of how we would register the POWDER Media type 
>> which actually looks pretty simple - being in a W3C Rec 
>> document means that IETF is likely to agree to the new type 
>> with little delay.
>> To get to the point, Mark's recommendation is that we
>> 1. Use a more generic @rel type of describedby (something 
>> other groups want as well btw)
>> 2. Register a POWDER-specific Media type. I guess ours would be
>> application/powder+xml
>> and
>> application/powder-s+xml
>> ???
>> Neither of these registration steps is particularly hard to do.
>> In terms of the WG's process, I suggest we teat this as a 
>> Last Call comment and deal with it when we resume in 
>> September - *unless* - Matt -
>>   you advise that /if/ we were to make such a change we'd 
>> require a new LC version, in which case we may need to take a 
>> couple of resolutions by e-mail before those docs you're 
>> working on are fully published (er, which I believe is 
>> scheduled for a week today)
>> Phil.
>> [1] http://tools.ietf.org/html/draft-nottingham-http-link-header-02
>> [2]
>> http://tools.ietf.org/html/draft-nottingham-http-link-header-0
>> 2#section-4.2
>> [3] 
>> http://lists.w3.org/Archives/Public/ietf-http-wg/2008JulSep/0122.html
>> [4] http://www.w3.org/2002/06/registering-mediatype
Received on Friday, 1 August 2008 08:58:23 UTC

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