RE: URI for XML schema and namespace

"Scott Hollenbeck" <sah-ietf@tengwar.com> Fri, 04 January 2008 16:04 UTC

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From: "Scott Hollenbeck" <sah-ietf@tengwar.com>
To: "'Julian Reschke'" <julian.reschke@gmx.de>
References: <FB2B4EC3-BE66-4192-8657-F318BF9F0329@osafoundation.org> <00a601c84edd$2ca4dcc0$0601a8c0@pc6> <000001c84ee8$789307a0$0223520a@charger> <477E568E.8050307@gmx.de>
Subject: RE: URI for XML schema and namespace
Date: Fri, 4 Jan 2008 11:04:21 -0500
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> -----Original Message-----
> From: Julian Reschke [mailto:julian.reschke@gmx.de] 
> Sent: Friday, January 04, 2008 10:54 AM
> To: Scott Hollenbeck
> Cc: 'tom.petch'; 'Apps Discuss'
> Subject: Re: URI for XML schema and namespace
> 
> Scott Hollenbeck wrote:
> >> -----Original Message-----
> >> From: tom.petch [mailto:cfinss@dial.pipex.com]
> >> Sent: Friday, January 04, 2008 8:19 AM
> >> To: Apps Discuss
> >> Subject: URI for XML schema and namespace
> >>
> >> What is the currently recommended form for a URI for an XML schema 
> >> and an XML namespace?
> >>
> >> The question has come up on ForCES where I, citing RFC3688 say it 
> >> should be urn:
> >> whereas the others cite RFC3470 to say that http: is recommended.
> >>
> >> Other opinions welcome.
> > 
> > Those folks looking at 3470 might have missed the third 
> paragraph in 
> > section
> > 4.9:
> > 
> > "In the case of namespaces in IETF standards-track 
> documents, it would 
> > be useful if there were some permanent part of the IETF's own web 
> > space that could be used for this purpose.  In lieu of such, other 
> > permanent URIs can be used, e.g., URNs in the IETF URN namespace"
> > ...
> 
> Unfortunately, the IETF so far hasn't followed the BCP's 
> advice to actually make http-based namespace URIs available.

As one of the authors of 3470 I can say very clearly that 3470 doesn't
provide advice on this point.  It states fact:

"Typically (and recommended practice in W3C) is to assign namespace names
using persistent http URIs."

Notice that there's no "may", "should", "must", etc.

> Thus, if it's considered A Good Thing to provide a 
> description of the namespace *at* the namespace URI - and 
> when would it not? - I'd suggest to still use an http based 
> namespace URL.
> 
> There are some IETF specs that for that very reason use URI 
> assigned by the W3C (Atom, Atompub), and lots of other IETF 
> specs use URIs on purl.org.

That's certainly a valid option.  I'm not saying that one is better than the
other. What I am saying is that people shouldn't think that 3470 recommends
one over the other.

-Scott-