Re: URI resolver was Re: RDDL and XML Schemas Proposed Recommendation

[Michael Mealling <michael@bailey.dscga.com>]

On Sun, Mar 25, 2001 at 03:48:48PM -0500, Jonathan Borden wrote:
> Michael Mealling wrote:
> > > > > Jonathan Borden wrote:
> > > as i said. per RFC 2396 when you resolve a URI you get back an
> > entity not a
> > > resource. you are conflating resource and entity.
> >
> > Oh lordy be carefull here. RFC 2396 defines the term Resource. Are you
> > using its definition or something else? Its kind of buried in the
> > semantics but RFC 2396 defines a Resource as something that is bound
> > to a URI.
> 
> Just to be clear, the binding of a resource to a URI need _not_ depend on
> network resolution. From RFC 2396:
> 
> "
>       Resource
>          A resource can be anything that has identity.  Familiar
>          examples include an electronic document, an image, a service
>          (e.g., "today's weather report for Los Angeles"), and a
>          collection of other resources.  Not all resources are network
>          "retrievable"; e.g., human beings, corporations, and bound
>          books in a library can also be considered resources.
> 
>          The resource is the conceptual mapping to an entity or set of
>          entities, not necessarily the entity which corresponds to that
>          mapping at any particular instance in time.  Thus, a resource
>          can remain constant even when its content---the entities to
>          which it currently corresponds---changes over time, provided
>          that the conceptual mapping is not changed in the process.
> "
> 
> Let me emphasize the statement: "The resource is the conceptual mapping ..."

Oh yes. Most emphatically so. The binding between a URI and its Resource
is a conceptual one.....

> > Also, you may be using the term 'resolve' in a much more
> > constrained sense
> > than Justin is.  IMHO, any time you find out some information about a URI
> > then you have just done the act of resolution. When I look in my
> > local cache in
> > my web browser that is resolution. When my entity resolver looks
> > in its local catalog, that is resolution. True, many URIs were designed
> > in a way that makes authoritative, global resolution impossible (the OID
> > URN namespace I defined in RFC 3061 for example). But that doesn't mean
> > that resolution in general is not possible...
> 
> Those example uses of the term "resolution" are fine but don't support the
> statement that "any time you find out some information about a URI then you
> have just done the act of resolution". I make a big distinction between URI
> resolution and looking up some information about a URI which I am using as a
> name.

That's fine. Just as long as we know we're using different definitions....

> > > Suppose this RDF is published by Amazon. And if I resolved this URN via
> > > Amazon I assume a book would arrive at my doorstep. _I would return the
> > > book_. If Amazon were to disagree I would call my Visa company
> > and complain.
> > > If I got nowhere I would call the FBI, my lawyer etc.
> >
> > It depends on what the RDF said. In this case what is authoritative
> > is Amazon's promise to send you said book. Amazon isn't authoritative
> > for the ISBN number, they're authoriative for the transaction you are
> > currently in. If they screwed up the ISBN urn in the RDF then yes, they
> > screwed up. But its no the fault of the URI....
> >
> > > Your concept of authority is interesting but I don't accept it.
> >
> > Authority for what? The ISBN organizatin is the _only_ entity that
> > can truly know what ISBN number goes with what book since they're
> > the ones that assigned it. If Amazon screws up their internal
> > inventory list then is it the ISBN agency that made the mistake? No,
> > its the mistake of Amazon for not checking with the authoritative
> > agency....
> 
> Umm.. who said I was ever using ISBN numbers... 

Justin was in his example....

> I may have simply looked up
> a book a (ficticious) Amazon catalog and ordered it. There can be an
> infinite number of URIs each -resolving- to an instance or instances of the
> same book, some might involve ISBN numbers.

Right. And the only way you know if some random URI you encounter on the
street really does resolve to that book is to either access it directly 
or ask the entity that assigned if that is actually the case.
(Beware, interesting values of sameness here. I'm assuming its a
functional equivalence who's context is your process.)
Its the same difference as using a card catalog number to go get the book
and checking its front matter as opposed to asking the librarian the
same question...

-MM

-- 
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Michael Mealling	|      Vote Libertarian!       | www.rwhois.net/michael
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