- From: Patrick Stickler <patrick.stickler@nokia.com>
- Date: Thu, 20 Nov 2003 15:41:50 +0200
- To: "ext Danny Ayers" <danny666@virgilio.it>
- Cc: <www-rdf-interest-request@w3.org>, "Graham Klyne" <GK@ninebynine.org>, "Jim Hendler" <hendler@cs.umd.edu>, "Dan Brickley" <danbri@w3.org>, <www-rdf-rules@w3.org>, <www-rdf-interest@w3.org>
On Thursday, Nov 20, 2003, at 13:52 Europe/Helsinki, ext Danny Ayers wrote: > > >>> I haven't fully digested your arguments yet, but would be grateful if >>> you >>> could answer one quick question: can't the functionality of MGET be >>> achieved >>> just using mimetypes? >>> >> >> No. Tried that. It doesn't work. Because you can't differentiate >> between request for a description of a resource, versus a request >> for a representation of a resource that happens to be a description >> of another resource. > > request for a description of a resource: > > http://example.org/xxx [mimetype:application/rdf+xml-description] > > request for a representation of a resource > > http://example.org/xxx [mimetype:application/rdf+xml] > > The first of these corresponds to MGET, the second to GET. Rather than > the > switch being on the verb, it's on the mimetype. If the latter > representation > happens to be a description of another resource, how is that > significant? > What is the logical difference between these approaches? Well, what happens when that description is available in RDF/XML, N3, N-Triples, XTM, HTML, etc.??? Do we have a parallel set of mime types, such that for any mime type x/y we have x/y-description? Or do we just forbid any other encoding than RDF/XML? I don't find either option the least bit appealing. It's really just a variant of the URI-suffix approach. E.g. append _META or such to the end of any URI to get the URI that denotes its metadata description. > >> Or if the resource in question has an RDF/XML representation, you >> can't use content negotiation to ask for a description in RDF/XML >> because how then do you differentiate between the RDF/XML >> representation >> and the RDF/XML description. > > Different mime type, recognized at both ends. A request for > "application/rdf+xml-description" means "please return a concise > bounded > description of the resource denoted by the request URI", the correct > behaviour of the server is confirmed by the returned Content-Type. > >> I even tried defining a distinct MIME type for concise bounded >> descriptions, but as I indicate above, in the case where you want >> a description of a description, it doesn't work > > I'd be grateful for an example of how this is different with MGET, it > sounds > like there's something I'm not grokking here. > See above. I.e. a description can have multiple representations... >> In short, there are certain "meta" distinctions which the SW needs >> that simply must be kept distinct from the existing web semantics. >> The distinction between requests involving a representation (web) >> and requests involving a description (sw) is one such distinction. > > Yes, I think you've made a good case for the distinction, but I don't > see > why this distinction couldn't be made through mime type negotiation > (or some > other existing mechanism)... > >> And IMO the cleanest way to implement that is with distinct methods >> such as MGET, MPUT, and MDELETE. > > Still not convinced... ;-) > Maybe the above comments, then, were useful to that end. Cheers, Patrick > Cheers, > Danny. >
Received on Thursday, 20 November 2003 08:44:09 UTC