W3C home > Mailing lists > Public > uri@w3.org > September 2001

Re: Excess URI schemes considered harmful

From: Mark Baker <distobj@acm.org>
Date: Wed, 26 Sep 2001 14:47:11 -0400 (EDT)
Message-Id: <200109261847.OAA19910@markbaker.ca>
To: robla@real.com (Rob Lanphier)
Cc: michael@neonym.net, uri@w3.org
Rob wrote;
> Are you saying that HTTP is the only protocol/scheme allowed to define
> equivalencies?  Wrong.

No no, nothing like that.  Just pointing out that HTTP has its own, and
that it's general enough to be useful for a variety of resource types
including, IMO, media types.

> A "ContentType:" scheme can define equivalencies.  Moreover, it can define
> equivalencies that map directly to equivalencies that already exist in the
> 822 header world.
>
> If the CTURI proposal doesn't define a way of mapping to a canonical form
> for comparison purposes, then I would agree that should be addressed.

I was being facetious.  Canonicalization is nasty work, as Donald knows.
My point was that I've seen no requirements for any notion of equivalence 
in the ContentType URI scheme, which would seem to me to be a starting
point for URI definition, not an afterthought.

Michael wrote;
> Right. How does that negate my assertion that URIs in and of themselves
> don't discuss equivalence of Resources outside lexical equivalence of
> the URIs that identify them?

Sorry, I didn't realize that was your assertion.  We agree about
that point.

> > IMO, yet another reason why using http URIs is Goodness.
> 
> and IMHO, yet another reason why HTTP semantics are not applicable across
> all URI schemes.

Not "all", but "lots of", "most", etc..

> HTTP's concept of equivalence is IMHO, fairly infantile.
> The equivalence semantics that something like RDF gives you are much
> more interesting and useful. but again, even the semantics that RDF
> gives you may not be useful for other applications such as directory
> services, network management, monitoring, rights management, etc...

So what *are* the equivalence requirements of ContentType?

MB
Received on Wednesday, 26 September 2001 14:45:19 UTC

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