W3C home > Mailing lists > Public > www-rdf-interest@w3.org > June 2001

URN to related RDF/how

From: Sampo Syreeni <decoy@iki.fi>
Date: Fri, 15 Jun 2001 12:40:22 +0300 (EEST)
To: <www-rdf-interest@w3.org>
Message-ID: <Pine.SOL.4.30.0106151203230.12636-100000@kruuna.Helsinki.FI>
If I remember correctly, there has been some prior discussion here on how to
map resources/URIs to their related metadata. Yesterday I ran into a very
interesting piece of foresight on behalf of the IETF naming/addressing
people, namely URCs (Uniform Resource Characteristics), an idea which I'm
not sure has been raised on-list before.

RFC2169 proposes a simple, easily implemented HTTP interface to resolve URIs
against a database located on an HTTP server, with a complete set of
resolution services that can be implemented. The obvious one is URN-to-URL,
of course, but there are also ones called N2C and L2C, meant to map from
URIs to resource characteristics. URCs are essentially synonymous with

The interface is simple: to resolve <URI>, one does an HTTP GET to
/uri-res/<service>?<URI>, where the interesting <service>s for our purposes
would be N2C (name to characteristic) and L2C (locator to characteristic).
The returned data format is not defined, but is rather communicated via the
standard HTTP Content-Type header. All the usual HTTP server responses can
be used.

In our case, we would probably return redirections to get to dedicated
metadata servers (like rdfdb; probably a future thing), straight XML encoded
RDF marked with the suitable content type (which begs the question, is
application/rdf+xml kosher?), or some newly registered content type for a
stream of triples (my personal favorite - you would use the query URI to do
a selection on the subject field of your table of triples, and just pump the
data back as-is). The RFC even describes a simple MIME content type for
lists of URIs, which could be used to list references to multiple RDF files
and future dedicated triplestores where metadata for the given document

Even if the RFC *is* experimental, one could likely build some nice
implementations on it (e.g. extending the idea to HTTP PUT would enable
Annotea-like apps to be built without having to configure the triplestore).
One might even consider throwing the thing into the standards track, if it
proved useful enough. What do you think?

Sampo Syreeni, aka decoy, mailto:decoy@iki.fi, gsm: +358-50-5756111
student/math+cs/helsinki university, http://www.iki.fi/~decoy/front
Received on Friday, 15 June 2001 05:40:24 UTC

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