- From: Dan Brickley <danbri@danbri.org>
- Date: Wed, 05 Dec 2007 20:51:34 +0000
- To: Tim Berners-Lee <timbl@w3.org>
- CC: Ian Davis <lists@iandavis.com>, "Sean B. Palmer" <sean@miscoranda.com>, David Booth <dbooth@hp.com>, www-tag@w3.org
Tim Berners-Lee wrote: > There is a major problem with this, though. Content negotiation is > just for different encodings of the SAME document. > You can content negotiate between PNG and JPG of the SAME picture. And SVG. Even quite lossily vectorised SVG... > Between text/plain and text/html of the SAME document. > Between RDF/xml and N3 of the SAME data. > > You cannot use conneg to return a completely different document, eg not > A but metadata bout A. > A and A' must carry exactly the same information, module an 'acceptable' > degree of degradation. > > When people conneg between HTML and RDF, the HTML is generated from the > RDF. Else it is a bug. I don't believe you on this, sorry! There's no webarch ordering of RDF over HTML any more than there is of PNG over JPG (or SVG). You're appealing to causal chains here, but I suspect the key point you're after is that both encodings stem from some common source. If I decide to generate my JPG from a PNG, or my PNG from a JPEG, or both from some hidden 3rd source, that's my right. But I think it's the "hidden 3rd source" (ie. the abstract "Work") that's the core idea here. You don't really mind if I generate the .rdf by extracting from HTML, or querying a private SQL store, do you? So long as they both have close enough information content that they can sensibly be considered to be imperfect renderings of the same (more or less fictional or at least hypothetical) "Work"? cheers, Dan
Received on Wednesday, 5 December 2007 20:53:45 UTC