- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Thu, 13 Sep 2007 18:54:44 +0200
- To: Reto Bachmann-Gmür <rbg@talis.com>
- Cc: Edward Bryant <edward.bryant@gmail.com>, semantic-web@w3.org
Reto, On 13 Sep 2007, at 10:32, Reto Bachmann-Gmür wrote: >> To learn what a URI refers to, don't look under the hood of the >> server. Look at the representations returned via HTTP. > While I'm not saying you should look under the hood of the server (or > guessing from the URI) looking at the representation returned by HTTP > may not be enough, e.g. > <http://Example.org/weather/ch/Bern/archive/2007-09-13> is probably > not > identifying the same resource as <http://Example.org/weather/ch/Bern> > even if (today) you would get the same representation. Well, I'd say that the content provider acts against his own interests if he publishes the same representation at both these URIs. It's a good practice to explain the nature of the resource somewhere within the representation. So somewhere in the first one from your example there might be the text “This is the archived weather report of 13 September 2007 for the city of Bern, Switzerland.” while in the second one we might find “This is the current weather report for the city of Bern, Switzerland.” Or some equivalent RDF triples if we talk about Semantic Web content. In the absence of such an explanation, an agent has little hope to find out what he's looking at. He cannot use the URI to reliably refer to anything, because he doesn't know what it will return tomorrow. Bookmarking it, linking to it, or passing it on to someone else, becomes a perilous affair. After all, I'd really like to know if I'm looking at today's or yesterday's weather report. A weather report that doesn't give me that information won't be popular. Thus, both content consumer and content provider benefit from representations that explain the nature of the resource. A second, less helpful choice would be external information about the resources. For example, there might be an RDF file or HTML file at <http://Example.org/weather/> that tells us what all the individual URIs refer to. Richard > > Cheers, > Reto >
Received on Thursday, 13 September 2007 16:55:13 UTC