Re: Using URIs to identify non-information resources

* Lars Marius Garshol
|
| . . . If you resolve a URI and it returns 303 you know that the URI
| might identify something (what you got back, or what it described,
| but you can't tell which),

* David Booth
| 
| That seems overly pessimistic.  If the URI owner wants you to know
| what the URI identifies then you certainly *can* tell which it
| identifies, because you will be forwarded to a document that will
| tell you explicitly.

Provided the "you" is a human being, yes, but surely the point of this
must be that a machine can determine whether the URI "identifies" a
resource or not.
 
| Furthermore, if it was a thing-described-by.org URI like
| http://thing-described-by.org?http://dbooth.org/2005/dbooth/ then
| you can tell by inspection (without performing an HTTP retrieval)
| that the URI does not directly identify an information resource
| [...]

That is true, *provided* that this way of doing things becomes
enshrined in web standards. So far this hasn't happened.

* Lars Marius Garshol
|
| . . . In an RDF graph of interesting size . . . there will be such a
| number of URIs that trying to dereference all of them is going to
| take so long that there is no way it can be worth the effort. . . .
 
* David Booth
|
| Again, this is an advantage of using thing-described-by.org URIs:
| those network accesses can be optimized away, as described at
| http://thing-described-by.org/#optimizing

Yes.
 
| In summary, if URI owners want you to know what their URIs identify,
| and they use thing-described-by.org URIs, then it seems to me that
| we have a scalable and deterministic solution.

Well, seen from the point of view of someone who's spent considerable
amounts of time trying to convert losslessly between RDF and Topic
Maps (where this distinction is built-in), everything is still chaos
in RDF-land on this particular point.

If people had consistently used thing-described-by.org (or the tdb:
URI scheme) that would indeed have solved it. However, this would have
required all URIs currently defined as part of
RDF/RDFS/OWL/SKOS/... to change, since not a single one of them
actually "identify" what they resolve to.  (I assume it's
uncontroversial that owl:Class "identifies" something other than what
it resolves to.)

The TAG ruling has the problem (from my point of view) that

 (1) it's too expensive to actually perform this check, and

 (2) even if you get a 303 back you don't know that that's because of
     something that was set up in say 2000 for some other reason. If
     the TAG had defined a new error code that would have avoided
     this particular problem.

-- 
Lars Marius Garshol, Ontopian         <URL: http://www.ontopia.net >
GSM: +47 98 21 55 50                  <URL: http://www.garshol.priv.no >

Received on Tuesday, 16 August 2005 13:54:44 UTC