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Re: URI for abstract concepts (domain, host, origin, site, etc.)

From: Dan Brickley <danbri@danbri.org>
Date: Fri, 26 Jun 2009 19:27:26 +0200
Message-ID: <4A4504FE.3050108@danbri.org>
To: Larry Masinter <LMM@acm.org>
CC: 'Pat Hayes' <phayes@ihmc.us>, 'Eran Hammer-Lahav' <eran@hueniverse.com>, 'Dan Connolly' <connolly@w3.org>, apps-discuss@ietf.org, www-tag@w3.org, 'URI' <uri@w3.org>
On 26/6/09 18:54, Larry Masinter wrote:
> # They aren't being treated differently. The normal syntax for naming
> # something in RDF is a URI reference with a fragid attached. The use of
> # a fragID cancels any assumptions that the URIreference denotes
> something connected with the HTTP protocol.
>
> How does it do that?
>
> # This is how RDF manages to
> # refer to galaxies, chemical elements, people, etc..
>
> Sounds like this is only in the context of RDF.

Yes and no.


Here's the "Yes": the idea is that if content is served as 
application/rdf+xml then the meaning of #foo is delegated to the 
relevant spec (http://www.w3.org/2001/sw/RDFCore/mediatype-registration 
? humm that's expired). The RDF mediatype doc says

"""Section 4.1 of the URI specification [6] notes that the semantics
    of a fragment identifier (part of a URI after a "#") is a property of
    the data resulting from a retrieval action, and that the format and
    interpretation of fragment identifiers is dependent on the media type
    of the retrieval result.

    However, in RDF, the thing identified by a URI with fragment
    identifier does not bear any particular relationship to the thing
    identified by the URI alone.  This differs from some readings of the
    URI specification [6], so attention is recommended when creating new
    RDF terms which use fragment identifiers."""

Here the "No": A URI that points to an RDF document constructed in this 
fashion, is (according to those persuaded this story works) supposed to 
be a URI for whatever galaxy, chemical element, person etc. the RDF is 
structured to represent.

In this way, http://danbri.org/foaf.rdf#danbri is a URI for me. Not just 
for RDF applications, but for any applications that care about the idea 
of URIs being URIs *for* things. The media-type registration that makes 
this so RDF-specific (RDF/XML-specific even) but the URI is supposed to 
be a URI for me, full stop, rather than "a URI for me, in RDF applications".

At this point people normally bring up the possibility of clashes across 
content-negotiated representations served at the same URI. The usual 
answer offered by return is "if that hurts, don't do it".

Dan
Received on Friday, 26 June 2009 17:28:09 GMT

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