- From: Tim Berners-Lee <timbl@w3.org>
- Date: Sun, 5 Jul 2009 23:09:40 -0400
- To: Pat Hayes <phayes@ihmc.us>
- Cc: <john.1.kemp@nokia.com> <john.1.kemp@nokia.com>, <danbri@danbri.org>, <skw@hp.com>, <www-tag@w3.org>
On 2009-07 -02, at 19:31, Pat Hayes wrote: > On Jul 2, 2009, at 10:48 AM, <john.1.kemp@nokia.com> <john.1.kemp@nokia.com > > wrote: > > ... > >> My reading of the MUST in RFC 2616: >> >> "If the abs_path is not present in the URL, it MUST be given as "/" >> when >> used as a Request-URI for a resource" >> >> is that "no path" is considered to be the equivalent of a path of >> "/". >> >> My reading would thus be that the URIs denote the /same/ thing. >> > > > What you cite refers to "when it is used as a Request-URI". That is > precisely why it does not necessarily refer to denotation. It is > centrally important in all these discussions to keep the two things > clearly separate. URIs can be used to request (access to) a network > resource, and they can be used as names, to denote a resource. I would prefer you to say, "URIs are used as names, to denote a resource, and the can be used to request information about the resource". When you ask and get a 303, then you are getting information back about the thing denoted, but you are not getting back the content of any named document. > The two functions are distinct, and need not coincide. They are not unrelated. > Some URIs can denote without being able to be usable to request > anything; others may work as requests but not denote what it is that > they request (according to http-range-14, a 303 redirect sets up > this possibility.) or rather, "Sometimes a request for information will be unsuccessful; sometimes they will not return that the resource is a document with a given content (according to http-range-14, a 303 redirect sets up this possibility.)" But clearly if the protocol is that when asking for information about <http://example.com > you must ask for information about <http://example.com/> , this is only useful if the two URI strings are used to denote the same thing. It is reasonable to canonicalise URIs in an RDF system so that in fact <http://example.com> never occurs in the system. Tim (Is a URI without the slash actually a valid production anyway -- not in a position to check just now?) > That wording of RFC 26167 that you cite may not have been intended > this way, but in fact it gives a perfect justification for a > decision that the "/"-less URI might denote something other than > what the "/"-normalized URI requests, as danbri originally proposed > > Pat Hayes >
Received on Monday, 6 July 2009 03:10:17 UTC