- From: Andreas Langegger <al@jku.at>
- Date: Mon, 21 Apr 2008 12:02:25 +0200
- To: "Mark Birbeck" <mark.birbeck@x-port.net>
- Cc: "Richard Cyganiak" <richard@cyganiak.de>, "Bent Rasmussen" <incredibleshrinkingsphere@gmail.com>, semantic-web@w3.org
hi there, interesting opinions here. Both I can acquire taste for. I think the problem that I need an HTTP request first is less and less there from now on because of mobile access everywhere. The fact, that I can figure out anything about a thing by doing a simple GET request is very very appealing. I think it makes things really easier. Another suggestion whould be to inject a protocol hint into the URI by the convention of a special sub-domain like http://doi.yourdomain.tld/somePath/resource/foo This could satisfy both opinions. Regards, Andy On Apr 21, 2008, at 11:44 AM, Mark Birbeck wrote: > > Hi Richard, > >> [...] >> >> The problem with URNs is that applications need to be modified or >> rewritten >> before they can know what a URN identifies. That's quite a high >> cost, and is >> one of the main reasons why many URN schemes never caught on -- not >> enough >> developers bothered to hardcode support for them into existing >> applications. >> >> Naming schemes that piggy-bank on HTTP don't have this problem, HTTP >> support is ubiquitous, and applications can learn that your URI >> identifies a >> person by making an HTTP request to retrieve a description of the >> identified >> thing. > > I'm afraid this is simply not true, and is actually to turn RDF on > its head. > > What a URI identifies has nothing to do with the protocol in 'pure' > RDF terms. In the following, my URI identifies a 'FOAF person', > regardless of anything that might be retrieved over HTTP: > > <http://example.org> a foaf:Person . > > Now, if these URIs didn't also serve as a means for retrieving > documents, then that would be the end of the story. But of course we > know that it isn't, and that sometimes these URIs also identify > web-pages. Given this fact, you could quite reasonably argue that a > URN is better, because when you use a non-retrievable URI, there is no > ambiguity; i.e., it is simply impossible for a URI to represent both a > person and a web-page if it doesn't begin with "http:". > > Which is why I say that getting the type of a resource by making an > HTTP request is to turn RDF on its head. It's to place a particular > problem caused by using one class of URIs (those that begin "http:") > right at the centre of RDF, when RDF itself is completely agnostic > about the detail of resource identifiers. > > In my opinion, it's not a great idea to build systems on the basis of > making a web request to check the 'type' of a URI. I think it's far > better to either use some non-HTTP scheme to identify the URI, or to > tack a fragment identifier on the end. > > But of course, I understand that people do see the need for such an > architecture, and I also know that this debate will run and run. :) > > Regards, > > Mark > > -- > Mark Birbeck > > mark.birbeck@x-port.net | +44 (0) 20 7689 9232 > http://www.x-port.net | http://internet-apps.blogspot.com > > x-port.net Ltd. is registered in England and Wales, number 03730711 > The registered office is at: > > 2nd Floor > Titchfield House > 69-85 Tabernacle Street > London > EC2A 4RR > ---------------------------------------------------------------------- Dipl.-Ing.(FH) Andreas Langegger Institute for Applied Knowledge Processing Johannes Kepler University Linz A-4040 Linz, Altenberger Straße 69 http://www.langegger.at
Received on Monday, 21 April 2008 10:03:05 UTC