- From: <noah_mendelsohn@us.ibm.com>
- Date: Tue, 26 Jun 2007 10:46:55 -0400
- To: John Cowan <cowan@ccil.org>
- Cc: Dan Brickley <danbri@danbri.org>, "Henry S. Thompson" <ht@inf.ed.ac.uk>, Pat Hayes <phayes@ihmc.us>, Tim Berners-Lee <timbl@w3.org>, www-tag@w3.org
Like Henry Thompson, I've never felt that the English word "representation" suggests either completeness or full fidelity. Indeed, had the history of the Web been a bit different, I personally would have had no objection to allowing retrieval of "representations" even of tangible objects that are not what we now call information resources. Although an information resource >can< be represented with full fidelity in a message, we clearly allow for less than full representations anyway, even with a 200. For example, I think it's OK to conneg between image/gif and image/jpeg for the same photo, yet almost surely at its native resolution GIF will preserve detail that jpeg doesn't, but when zooming most viewers would feel that jpeg remains truer to what is (presumably) the photograph itself. We also allow for foreign language translations of text information resources, even though those almost surely lose some nuance. So, even in the Web as deployed today, is precedent for representations of information resources being incomplete or otherwise imperfect. In principle, I would think we could have representations of concrete objections as well. However, I have come to believe that: * The distinction between information resources and non-information resources is a useful one. * Having HTTP GET indicate in the results of an interaction whether what has been contacted is in fact an information resource, and thus whether the representation stands in the sort of relationship to the resource that we expect for information resources (which >can< by definition be faithfully sent in message), is useful. * We should respect the precedent that's been established for signalling this, which is to use HTTP status code 200. So, I would have not have had objections in principle if the Web had done this differently, but I think the path we're on is OK. 200 means information resource. We now have to establish best practice in the case that it's a non-info resource, which is what the TAG is lately discussing. Noah -------------------------------------- Noah Mendelsohn IBM Corporation One Rogers Street Cambridge, MA 02142 1-617-693-4036 --------------------------------------
Received on Tuesday, 26 June 2007 14:47:14 UTC