W3C home > Mailing lists > Public > xml-uri@w3.org > May 2000

Re: A new proposal (was: Re: which layer for URI processing?)

From: Jonathan Borden <jborden@mediaone.net>
Date: Thu, 25 May 2000 17:53:24 -0400
Message-ID: <00cd01bfc693$a99acd50$0a2e249b@Synapse>
To: "John Cowan" <jcowan@reutershealth.com>
Cc: <xml-uri@w3.org>
John Cowan wrote:

> Jonathan Borden wrote:
>
> > Is there a class of problems caused by relative URIs that isn't also
caused
> > by un-normalized URIs?
>
> Yes!  The fact that two apparently distinct absolute URIs (e.g.
> "http://one.example.com/foo" and "http://two.example.com/foo") refer to
the same
> thing is a very different problem from the fact that apparently identical
> relative URI references (e.g. "foo" in doc1 and "foo" in doc2) refer to
> different things.

Actually the point is that both absolute URIs may point to different things
over time and that in terms of 'identity' URIs are only invariant in terms
of their name not what is referenced.

> Nothing but confusion is gained by mixing up these issues.
>

What I am saying is if referencing a URI is *defined* to determine the
document type (via schema), that this document type may vary depending on
time and place regardless of whether the URI is relative or absolute. This
example was posted in response to the "detonator" example.

In order to really determine whether relative URIs actually cause a problem,
you need to show a concrete example of a problem unique to relative URIs. I
have no doubt such problems exist but if we bring these out in the open we
can see exactly what the implications of a proposed change in the namespace
spec might bring.

My current opinion is that one who defines a relative URI for a namespace is
responsable for assuming such risks and unless there are real world and very
significant problems which occur - caveat emptor.

Jonathan Borden
Received on Thursday, 25 May 2000 18:01:05 UTC

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