- From: Dan Connolly <connolly@w3.org>
- Date: 14 Feb 2002 22:29:42 -0600
- To: Aaron Swartz <me@aaronsw.com>
- Cc: RDF Core <w3c-rdfcore-wg@w3.org>
On Thu, 2002-02-14 at 20:26, Aaron Swartz wrote: > On 2002-02-14 3:08 PM, "Dan Connolly" <connolly@w3.org> wrote: > > >> I really can't agree with this. It's our problem that RDF uses this > >> non-standard piece of Web architecture, and in doing so has incurred all > >> sorts of problems. If we're going to be the Resource Description Framework, > >> we need we're actually describing resources. My ideal resolution would look > >> like: > >> > >> o The WG resolves that the use of absolute URIs with fragment IDs is a > >> to identify Web resources is relatively incompatible with current Web > >> architecture. > > > > ????? > > > > Er.. it's the very heart of web architecture: > > > > The principle that anything, absolutely anything, "on the Web" > > should identified distinctly by an otherwise opaque string > > of characters (A URI and possibly a fragment identifier) is > > core to the universality. > > > > -- http://www.w3.org/DesignIssues/Architecture > > RFC2396 would agree with you except for the "and possibly a fragment > identifier" bit. RFC2396 does not say that a URI+fragid does not identify anything. RFC2396 is silent on what a URI+fragid identifies. > Same with Roy Fielding's dissertation (which clearly > explains the reasons why this was an explicity design decision) I was there, and I don't think it was an explicit design decision; it was consensus by exhaustion. The software for URIs handles fragment identifiers. The specs are a little more conservative, but not inconsistent. > and probably > the many people who have invested in URI syntax, and don't want to go back > and fix their HTTP clients, proxies, servers or other software (and maybe > hardware) to support this addition of fragment identifiers. All the software works with fragment IDs today. It has since 1989 or so. > >> o We recommend that RDF users refrain from using '#' in their Resource > >> identifiers and namespaces. RDF developers and tool creators may present > >> a warning to the user when using resource identifiers with '#' in them. > > > > Why? rdf:type has a # in it, after all. How can they avoid it? > > Why would they? > > Perhaps I wasn't clear. I meant ones that they were creating (like if I > wanted to come up with a namespace for my new vocabulary set, or my poodle). > > > I don't see any explanation of a problem here. > > We've discussed it several times on and off list, but I could reitierate it > for you. The issue is that: > > a) In the REST architectural model (which the TAG seems to be agreeing > about) fragment identifiers only make sense within the context of an HTTP > response (a bag of bits). I disagree: a URI with a fragment makes sense as an identifier in the global scope of the web. > They identify parts of a document, not general > Resources like full URIs. A part of a document is 'something with identity', i.e. a resource. > b) Deployed code doesn't support fragment identifiers as first-class objects yes, it does. > -- I can't ask an HTTP proxy about them, I can't query an HTTP server about > them, etc. Why would you expect to be able to? That's not how they work. > And this is by design... > > <MikeM> fragmetns are client side thing..... > - in #rdfig > > Exactly! RDF has created this problem by taking what in Web Architecture is > designed to be a client-side thing, the last step of resolution. TimBL > explained this at the first W3C technical plenary: "[an HTTP client] puts > the fragment ID in its pocket". Yes, and how is that a problem? > Also, in his Axioms of Web Architecture: The Web Model[1], Tim explains how > a client holds on to the fragment ID so that it can pass it to the > presentation object. > > [1] http://www.w3.org/DesignIssues/Model > > He's even got a nice diagram to explain it. I'm not sure how much clearer it > can be that a fragment only makes sense in the context of presenting a > document. Yes, a fragment identifier is qualified by the stuff before the #. That's how it works. How is that inconsistent with RDF? > >> b) maintaining backwards-compatibility but > >> c) lay the ground work for future WGs to fix this bug > > What bug? > > The bug that RDF is incompatible with Web Architecture, as explained above. I still don't see the bug. Can you give a specific example of a failure mode? > <MikeM> seriously, RDF's use of frags has caused so many problems.. If RDF > needs something like it that badly then make it a new URI scheme that does > it _right_ > > -- > [ "Aaron Swartz" ; <mailto:me@aaronsw.com> ; <http://www.aaronsw.com/> ] -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 14 February 2002 23:29:16 UTC