W3C home > Mailing lists > Public > www-rdf-interest@w3.org > April 2002

Re: Disambiguation; keeping the "U" in "URI"

From: Mark Baker <distobj@acm.org>
Date: Thu, 25 Apr 2002 14:48:55 -0400
To: Sandro Hawke <sandro@w3.org>
Cc: Mark Baker <distobj@acm.org>, Nick Matsakis <matsakis@mit.edu>, www-rdf-interest@w3.org
Message-ID: <20020425144855.J13270@www.markbaker.ca>
On Thu, Apr 25, 2002 at 11:58:34AM -0400, Sandro Hawke wrote:
> In HTTP, when you say "GET foo", it should be read as "GET the
> contents currently stored in foo".  

RFC 2616 does have some text in it which is unfortunate, but I believe
I heard Roy say that it was the best he could get concensus on.

Since you're more on-side with TimBL than Roy here, let me bring up a
point that I believe demonstrates an inconsistency in TimBL's thinking;

 "Any place I can use a URI I can use any URI."
  -- http://www.w3.org/DesignIssues/UI.html

and take your choice of any HTTP RFC;

  "Request-Line = Method SP Request-URI SP HTTP-Version CRLF"
  -- RFCs 1945, 2068, 2616

This demonstrates that HTTP can be used to resolve any URI, not just
those in the HTTP URI scheme.  The reason this is so, is because
HTTP GET is defined/designed to be general enough to do this.  See
WIRE[1] for example.

So, if HTTP GET is this general, and the HTTP URI scheme is bound to
HTTP's application semantics (and currently, the HTTP protocol itself),
then doesn't it follow that HTTP URIs can't identify anything?  If not,
why not?  Where's the flaw in my thinking?

> While I think this is by far the most logical, consistent, and widely
> held view, it doesn't work to well with
>    <> dc:creator [whatever].
> unless you read dc:creator to be talking about the content retreived
> from the thing which is it's rdf subject, which is kind of a stretch.
> 
> What happens when the document at some location is replaced by one
> with a different creator?  A whole raft of dc:creator triples become
> incorrect.   Sigh.

There is absolutely no problem with doing this, so long as you have
enough URIs to maintain uniformity.  Let's say that a restaurant
publishes a daily menu;

http://restaurant.example.org/menu/

This URI identifies the current menu for the day.  Each day, GET will
return something different.

Now let's say that yesterday, our Chef de Cuisine created the menu.  He
publishes it at;

http://restaurant.example.org/menu/2002-04-24.html

So we can say;

<http://restaurant.example.org/menu/2002-04-24.html> dc:Creator
 <http://restaurant.example.org/people/chef-de-cuisine/>

A GET on "http://restaurant.example.org/menu/" yesterday would have
returned the content from that URI, with the Content-Location header
set to its URI.

Today, the Chef de Partie creates it;

<http://restaurant.example.org/menu/2002-04-25.html> dc:Creator
 <http://restaurant.example.org/people/chef-de-partie/>

and a GET on /menu/ would return that content with the Content-Location
header set.

What's the problem with that?

 [1] http://www-old.ics.uci.edu/pub/ietf/http/draft-girod-w3-id-res-ext-00.txt

MB
-- 
Mark Baker, Chief Science Officer, Planetfred, Inc.
Ottawa, Ontario, CANADA.      mbaker@planetfred.com
http://www.markbaker.ca   http://www.planetfred.com
Received on Thursday, 25 April 2002 14:42:06 GMT

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