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Re: IETF XML formats use lots of URNs for namespace names

From: Dan Connolly <connolly@w3.org>
Date: Tue, 15 Mar 2005 10:29:52 -0600
To: "Henry S. Thompson" <ht@inf.ed.ac.uk>
Cc: "Martin J. Duerst" <duerst@w3.org>, www-tag@w3.org
Message-Id: <1110904192.8271.19.camel@localhost>

On Tue, 2005-03-15 at 11:17 +0000, Henry S. Thompson wrote:
> Dan Connolly <connolly@w3.org> writes:
> 
> > [what's this use of URNs for namespaces in IETF work ???]
> >   targetNamespace="urn:ietf:params:xml:ns:pidf:geopriv10
> > [from] http://ietfreport.isoc.org/idref/draft-ietf-geopriv-pidf-lo/
> 
> So it turns out this is based on something called the IETF XML
> Registry (RFC 3688) [1], which seems to me to interact with various
> aspects of Web architecture.

Yes, re-reading it, I find...

"ns -- XML Namespaces [W3C.REC-xml-names] are named by a URI.  They
      have no real, machine-parseable representation."

vs.

"Another benefit of using URIs to build XML namespaces is that the namespace URI can be
used to identify an information resource that contains useful information, machine-usable
and/or human-usable, about terms in the namespace. This type of information resource is
called a namespace document.

...

The owner of an XML namespace name SHOULD make available material intended for people
to read and material optimized for software agents in order to meet the needs of those
who will use the namespace vocabulary."

 -- http://www.w3.org/TR/webarch/#namespace-document

Bjorn points out
  http://www.iana.org/assignments/xml-registry/

which means each urn:ietf:... resource has 2 names, which goes against..

"Good practice: Avoiding URI aliases

A URI owner SHOULD NOT associate arbitrarily different URIs with the
same resource."

 -- http://www.w3.org/TR/webarch/#avoid-uri-aliases



>   It provides for 'registering' assigned
> URNs for namespaces, DTDs, W3C XML/RDF Schemas and public identifiers.
> 
> It mandates the creation of a server by IANA (not yet in existence, I
> don't think), which will serve the definitive definition of the
> registered things.  It also says that you shouldn't count on the
> server to give you DTDs or schema documents . . .
> 
> It says nothing whatsoever about versioning. . .
> 
> This whole thing makes me quite nervous . . .
> 
> ht
> 
> [1] http://ietfreport.isoc.org/idref/rfc3688/
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Tuesday, 15 March 2005 16:29:55 GMT

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