Re: URI for XML schema and namespace wasRe: urn was Re: Model draft

["Joel M. Halpern" <[e-mail]>]

As I read this, if we had a stable URL that actually could point to the
schema, that would be better.
But since the proposed URL does not actually point anywhere, we should
not use a non-resolvable URL.

So I will change it to a URN.  (Grudingly, because the conversation
seems to say that over all the IETF is doing the wrong thing.)

Joel

tom.petch wrote:
> I said I would raise the question of what to use to name a namespace on the Apps
> Discuss list and I did, under the Subject above.  The discussion was most
> interesting with perhaps the most significant view being that of Chris Newman,
> as follows
> ============================================
> Date: Fri, 04 Jan 2008 15:46:02 -0800
> From: Chris Newman <[e-mail]>
>
> As Applications Area Director, I'm not aware of anyone ever asking for that.
>
> I'm holding a discuss position on:
>    draft-narten-iana-considerations-rfc2434bis-08
> because the present text forbids use of IANA URLs and I consider that an
> unacceptable new restriction for IANA considerations.
>
> Current IETF practice discourages use of IANA URLs in IETF specifications.
> However, we have one case, RFC 4790, where stable iana.org http URLs are
> provided to registry elements and that was done with IANA's permission.  In that
> case, the registry was created to be useful to both the IETF and the W3C. The
> stable http URLs make the W3C happier so it was worth doing that way.
>
> I would support a similar approach for iana.org http XML namespaces if someone
> spent the time to write up the rules and get IANA's consent.
>
> Using an ietf.org http URIs for XML namespaces is a bad idea.  The IETF has
> deliberately kept the registry function for our standards separate and I
> consider that a feature.  Also, ietf.org is operated by the Secretariat
> function so using that domain for registrations would require additional (and
> more expensive) coordination than iana.org.  It _might_ be feasible to set up a
> redirect from ietf.org to iana.org for XML namespaces, but I worry that's just
> one additional level of complexity where things could break (especially if we
> transition the secretariat function between vendors periodically as we're in the
> process of doing now).
>
> To summarize the options:
> 1. URNs for XML namespaces -- present IETF common practice
> 2. non-IETF http URLs for XML namespaces -- acceptable
> 3. iana.org http URLs for XML namespaces -- nobody has tried this, seems
> feasible to me.
> 4. ietf.org http URLs for XML namespaces -- nobody has tried this.  I think it's
> a bad idea.
>
>                 - Chris
>
> David Harrington wrote on 1/4/08 11:47 -0500:
>
>> Has anybody fashioned an explicit proposal for the establishment of
>> permanent IETF URIs?
>>
>
> ============================================
>
> Points to emerge were that whatever is used should be persistent and stable.  I
> also note this exchange between Scott Hollenbeck and Julian Reschke.
>
>> -----Original Message-----
>> From: Julian Reschke [mailto:[e-mail]]
>> 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:
>>> 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-
> ==============================================
>
> So RFC3470 does not make a recommendation:-)  And, unless and until there is a
> proposal of the kind that Chris Newman alludes to, I think that the urn: scheme
> is the best choice.
>
> Tom Petch
>
> ----- Original Message -----
> From: "tom.petch" <[e-mail]>
> Sent: Friday, January 04, 2008 2:20 PM
> Subject: urn was Re: Model draft
>
>
>> ----- Original Message -----
>> From: "Joel M. Halpern" <[e-mail]>
>> To: "tom.petch" <[e-mail]>
>> Sent: Wednesday, January 02, 2008 3:09 PM
>> Subject: Re: Model draft
>>
>>
>>> There appear to be two issues you are raising with the name space
>>> declaration in this document.  One issue is whether the version goes
>>> before or after the model scoping.  Because the schema and its semantics
>>> relate to the protocol as well as the model, it seemed to go in the
>>> order we have it (version, lfmmodel.)  However, after reading your
>>> comment and thinking about it, I suspect that you are correct about the
>>> ordering, and it should be lfbmodel then 1.0.
>>>
>>> The second issue appears to be our use of an http uri rather than a
>>> field delimited urn as the namespace.  The use of HTTP URIs seems fully
>>> conformant.  And the use of web space URIs seems recommended by RFC
>>> 3470.  The use of URNs for namespaces is offered there as a fallback
>>> alternative.  So it is not clear to me what the problem is with our usage.
>>>
>> Not a big problem, perhaps not even little one.  I agree that HTTP URIs are
>> recommended by RFC3470 but there is a reference there to ongoing work in an
> I-D
>> that later became RFC3688, so for me, RFC3688 trumps RFC2470 - and there, as I
>> read it, urn are recommended.  Certainly I see a lot of urn and cannot recall
>> when I last saw a HTTP URI, apart from here.  I will ask on apps-discuss and
>> come back to you.
>>
>> Tom Petch
>>
>>> Yours,
>>> Joel M. Halpern
>>>
>>> tom.petch wrote:
>>>> I think that the URIs are not quite right yet.
>>>>
>>>> As per RFC3688, the targetNamespace should be a urn, eg
>>>>
>>>>  targetNamespace="urn:ietf:params:xml:ns:forces:lfbmodel:1.0"
>>>>
>>>> and the schema needs a name if it is to be registered with IANA, eg
>>>>
>>>> "urn:ietf:params:xml:schema:forces:xxx:1.0"
>>>>
>
>