- From: Graham Klyne <GK@ninebynine.org>
- Date: Fri, 31 May 2002 12:35:29 +0100
- To: Patrick Stickler <patrick.stickler@nokia.com>
- Cc: www talk <www-talk@w3.org>
Patrick, I don't really disagree with much of what you say here. I don't plan debate the finer points. But I'll suggest that even in an open network there's a place for proprietary usage. Many of the more successful standards started out as proprietary usage which found a wider audience. In my case, the /id.../ convention is my way of informally indicating an intended usage. The actual usage will determine the appropriate response when trying to retrieve a document. As for using RDF to expose information about the URI usage within a domain, I think that's a fine idea, and another debate. I don't yet feel the need to enter those waters. #g -- At 02:20 PM 5/30/02 +0300, Patrick Stickler wrote: >On 2002-05-30 12:07, "ext Graham Klyne" <GK@NineByNine.org> wrote: > > > At 09:15 AM 5/30/02 +0300, Patrick Stickler wrote: > >> On 2002-05-29 15:05, "ext Graham Klyne" <GK@ninebynine.org> wrote: > >> > >>> .. (e.g. I have a > >>> convention in my web space that http://id.ninebynine.org/ is used for > such > >>> abstract identifiers. I think it helps to clarify the intent, but it > >>> doesn't make all the problems go away, such as my second question above.) > >> > >> Tut, tut, Graham ;-) > >> > >> How is this any different from voc://ninebynine.org/... except that the > >> convention is not standardized and the semantics that the URI denotes an > >> abstract resource is specific/proprietary to your own practices? > > > > Exactly that! > > > > It's not standard, and it's something that I as owner of the domain space > > choose to do. > > > > It does nothing to change the universal elements of interpretation of a > URI. > >But a human (or software agent) would have to understand the prose >provided on your site to know that a 404 response was not actually >a true error, but that the resource is simply not web-accessible. > >I.e. a client that recieves an http: URI expects it to resolve to >something. It has a traditional interpretation as denoting a web >accessible resource. If the resource is e.g. the abstract concept >of "love" then anything that an HTTP server might return with a 1xx >response is misleading to the client, since that resource itself >could not be returned, only knowledge about that resource. > >If having 'id.' as part of one of your URLs helps you, fine, but I >don't intend to try to understand all the internals of site specific >URLs. I will only concern myself with (a) the semantics defined >for the specific URI scheme, or (b) knowledge defined about the >specific resource based on its otherwise opaque URI. (note that >URI class taxonomies are a disjunct issue entirely) > >Thus if we are to capture in the URI itself whether a given resource >is or is not web-accessible, it must be done with the URI scheme. >That's it. What is within the scope of the host domain is not >interesting or useful with regards to global architecture (and >specifically should not be). > > >> This seems to conflict with your earlier expressed opinion that the URI > >> should not reflect itself whether the resource is or is not "on the web" > > > > Er, no: what I said was: > > [[ > > (By which, I mean that I don't accept them as universal proposals: I have > > no argument with their use as a convenient mechanism by you or any other > > developers. ... > > ]] > > > > I might have added "domain owners". > >Fair enough. Though what if you had a means to expose a portion >of the semantics of a URI scheme which would apply to all instances >of that scheme, and do so globally, and in RDF, such that any >application could obtain that specification and use it to >interpret any instance of that URI scheme. > >Then, it would not be proprietary, but open and ultimately extensible. > >I.e, just as folks publish DTDs, XML Schemas, RDF Schemas, etc. >to expose the structure and semantics of content models, so >one could publish the semantics of a URI scheme that would allow >all applications to interpret URIs of that scheme consistently, >yet not have internal native knowledge about the scheme itself. > >So I can, eg. define in RDF that URIs of the scheme voc: denote >non-web accessible resources, and any application that is presented >by such a URI then knows that it is meaningless to try to dereference >that URI. All that is required is a standardized ontology for >expressing a basic level of semantics about URI schemes useful for >most web agents needs when dealing with interpretation of URIs. > >On the other hand, in the case of http: URIs which denote non-web >accessible resources, such knowledge would need to be defined for >each and every instance, which is a huge maintenance burden. Some >may prefer or require that level of resolution, but I think most >folks will prefer to enjoy the economy of URI scheme-wide semantics. > >Still, having metadata specific response codes and methods would >work in either case. How the server determines the accessibility >of a resource remains open. It could be based on URI scheme or >per-resource knowledge. > >Which method one chooses depends on the nature of the resource >and the abilities/needs of the creator. > >Rather than 100s or 1000s of sites all employing their own >proprietary URI tricks to reflect whether the denoted resource >is or is not web accessible, wouldn't it be better to (a) use >a smaller set of standardized URI schemes to reflect such >distinctions and (b) express such semantics for those schemes >in RDF so applications need not maintain such knowledge natively? > >After all, your approach suggests we could forgo schemes such >as mailto: or ftp: in place of site specific syntactic conventions, >such as http://mailto.nokia.com/patrick_stickler, etc. because >the site owner has said somewhere what the nature of such >resources are. > >There is a clear tradition of distinguishing the accessibility >characteristics of URIs based on the URI scheme, so why not also >the non-accessibility characteristics? 'http:' means resolvable >via HTTP. 'voc:' means not ever resolvable or accessible. Simple, >clear, concise, consistent, and (ideally) standardized. > >Eh? > >Regards, > >Patrick > >-- > >Patrick Stickler Phone: +358 50 483 9453 >Senior Research Scientist Fax: +358 7180 35409 >Nokia Research Center Email: patrick.stickler@nokia.com ------------------- Graham Klyne <GK@NineByNine.org>
Received on Friday, 31 May 2002 08:35:20 UTC