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Re: resource and representation

From: Paul Prescod <paul@prescod.net>
Date: Fri, 05 Jul 2002 04:21:34 -0700
Message-ID: <3D25813E.D0CB21E4@prescod.net>
To: Patrick Stickler <patrick.stickler@nokia.com>, WWW TAG <www-tag@w3.org>

Patrick Stickler wrote:
> 
>...
> 
> No. I didn't understand that GET could return something other than
> a "representation of full fidelity".

So you figured that a 90% JPEG is not an acceptable representation of a
BMP?

>...
> But I don't see it working well if at all with software agents
> who are unnable to discern that a photo of Paris is not Paris
> itself. 

If the software agent is programed to understand web architecture then
it knows that what it gets back from GET *cannot* *ever* *be* the
resource.

>....
> Well, ahem, tell that to the folks wanting a URI to denote both
> an abstract namespace and a namespace document ;-)

Patrick: the namespace document is a representation. It is *metadata*
associated with the resource not *the data* nor *the resource*.

>..
> Will the namespace document have its own URI? If not, how can
> I express statements in RDF about the namespace versus the
> namespace document?

That's the million dollar question that RDF people have to answer. One
can imagine a variety of solutions like an extension to URIs or
different primitives for making statements about representations versus
resources. But it is much more easily solved in RDF rather than HTTP.

How do you make a statement about a symlink rather than the file it
points to (another "seeming" ambiguity)? It depends on the program
making the reference. Maybe it gives you that ability or maybe it is
incomplete and it doesn't. Either way, you don't whine that the file
system is broken. (not that the Web is a file system...it is only an
analogy)

I think that there is a /# hack that is supposed to fix this problem but
don't know the details enough to know whether it is successful.

>...
> In this regard, HTTP and RDF are in a way at odds, since to HTTP,
> one URI is enough but for RDF that constitutes a problemmatic,
> if not unworkable, ambiguity.

Now we're making progress. We agree that there is an incompatibility. We
agree that an RDF-side solution is "not unworkable". Why not just go
make it work rather than arguing about changing a long-deployed spec?

-- 
Come discuss XML and REST web services at:
  Open Source Conference: July 22-26, 2002, conferences.oreillynet.com
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Received on Friday, 5 July 2002 07:22:09 GMT

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