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Re: Excess URI schemes considered harmful

From: Mark Baker <distobj@acm.org>
Date: Wed, 26 Sep 2001 11:59:44 -0400 (EDT)
Message-Id: <200109261559.LAA18510@markbaker.ca>
To: michael@neonym.net
Cc: robla@real.com (Rob Lanphier), uri@w3.org
Oops, sorry, missed this one.

> On Tue, Sep 25, 2001 at 02:52:50PM -0400, Mark Baker wrote:
> > There's different degrees of equivalency at play here.
> > 
> > It is the case that if two HTTP URIs are equal, that they necessarily identify
> > the same resource (also see RFC 2616 sec 3.2.3).  It is not the case that if 
> > two HTTP URIs are *not* equivalent (even modulo 2616/3.2.3), that they do 
> > *not* represent the same resource.  The only way to determine whether two 
> > non equivalent HTTP URI represent the same resource latter is to have 
> > authoritative info about that equivalence (or lack thereof).  One way for 
> > that authoritative info to be communicated is with an HTTP redirect.
> > 
> > Even the current CTURI draft has the latter problem, as the encoding is not
> > canonical.
> 
> This is indeed the case with _all_ URIs. Equivalence of resources across 
> schemes is iff the URIs are lexicographically equal.

Untrue.  See below.

> URIs themselves
> express no other type of equivalence other than that since equivalence
> is always application specific and more often than not is also context
> specific. Unless you have some application specific knowledge talking
> about equivalence of Resources is a very dangerous and, IMNSHO, simply
> a Bad Thing To Do...

Luckily, HTTP is an application protocol, so is in a very good position
to define application specific knowledge/context, such as when http
URIs are "equivalent" or not.  Non-http URI schemes don't have that
advantage.

IMO, yet another reason why using http URIs is Goodness.

MB
Received on Wednesday, 26 September 2001 12:01:41 UTC

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