{"id":819,"date":"2012-03-01T00:29:52","date_gmt":"2012-03-01T00:29:52","guid":{"rendered":"http:\/\/blog.soton.ac.uk\/webteam\/?p=819"},"modified":"2012-03-04T20:48:16","modified_gmt":"2012-03-04T20:48:16","slug":"firing-range-14","status":"publish","type":"post","link":"https:\/\/blog.soton.ac.uk\/webteam\/2012\/03\/01\/firing-range-14\/","title":{"rendered":"Firing Range-14"},"content":{"rendered":"

So there’s a call for suggestions to fix\/replace http range14<\/a>.<\/p>\n

If you’re not familiar with this. The basic sitution is that we use URIs to represent real world things, and if you resolve them they give a “303 See Other” to redirect you to a document of interest, presumably about the subject you asked about.<\/p>\n

eg.<\/p>\n

I, the person, am identified by URI: http:\/\/id.ecs.soton.ac.uk\/person\/1248<\/a><\/p>\n

My profile page, an HTML document, is identified (& located) by URL: http:\/\/www.ecs.soton.ac.uk\/people\/cjg<\/a><\/p>\n

My FOAF Profile, an RDF+XML document containing machine-readable facts about me is identified (& located) by URL: http:\/\/rdf.ecs.soton.ac.uk\/person\/1248<\/a><\/p>\n

If you resolve my URI in a web browser, it’ll pop up my profile page. You can see how by typing this on the UNIX or OSX terminal:<\/p>\n

curl -I http:\/\/id.ecs.soton.ac.uk\/person\/1248<\/pre>\n
The response will be more or less like this:<\/p>\n
HTTP\/1.1 303 See Other<\/strong>\r\nDate: Wed, 29 Feb 2012 23:52:16 GMT\r\nServer: Apache\r\nX-Powered-By: PHP\/5.3.3\r\nLocation: http:\/\/www.ecs.soton.ac.uk\/people\/cjg<\/strong>\r\nConnection: close\r\nContent-Type: text\/html; charset=utf-8<\/pre>\n
Which means go look at the URL in the “Location:” bit. The 303 indicates “See Other” rather than the normal “Moved”, which implies it might not actually be the same thing.<\/p>\n
For added complexity, if you tell the web server you prefer to get RDF+XML documents, by typing<\/p>\n
curl -H'accept:application\/rdf+xml' -I http:\/\/id.ecs.soton.ac.uk\/person\/1248<\/pre>\n
You get back<\/p>\n
HTTP\/1.1 303 See Other<\/strong>\r\nDate: Wed, 29 Feb 2012 23:54:39 GMT\r\nServer: Apache\r\nX-Powered-By: PHP\/5.3.3\r\nLocation: http:\/\/rdf.ecs.soton.ac.uk\/person\/1248<\/strong>\r\nConnection: close\r\nContent-Type: text\/html; charset=utf-8<\/pre>\n
This is bloody hard for people to get their heads around, and not obvious unless you really grok how the web was designed. However, for me, the real screw-up in all of this is using “http:” to represent something which isn’t a document… It’s not like we weren’t already using http: https: gopher: ftp: urn: mailto: tel: etc. (OK, nobody remembrs gopher)<\/p>\n
I think it’s daft to use the same protocol to unqiuely identify real-world objects AND documents on the web. I have to explain this again and again to each person learning RDF, and it won’t take off if people can’t figure it out for themselves, like HTML, JSON, XML etc.<\/p>\n
\ufeffSchema.org<\/h2>\n
If you’ve not yet seen schema.org<\/a>; it’s a website which presents a schema for information friendly to search engnges. It mostly doesn’t idenify ‘things’ at all, just defines a structure and literal properties of items in that structure (eg. start time of an event, name of a person). I hear it uses URLs to identify things which isn’t as crazy as it sounds if you define the relationships correctly. eg.<\/p>\n
<http:\/\/www.soton.ac.uk> *hasMember* <http:\/\/www.ecs.soton.ac.uk\/person\/cjg> .<\/p>\n
That’s an utterly reasonable statement if *hasMember* is defined as meaning “the group or organization which is the primary topic of the first document, has a member which is the primary topic of the second document”. It’s ugly, but entirely semantically sane. In slightly<\/em> more formal terms;<\/p>\n
?X *hasMember* ?Y<\/p>\n
implies<\/p>\n
?X foaf:primaryTopic ?X-topic .
\n?Y foaf:primaryTopic ?Y-topic .
\n?X-topic foaf:member ?Y-topic .<\/p>\n
My proposal; infra:<\/h2>\n
UPDATE 3: So it turns out that just like my ‘primaryTopic.net’ namespace idea, this is also an idea that’s been suggested before, in far more careful detail: tools.ietf.org\/html\/draft-masinter-dated-uri-10<\/a><\/p>\n
So my analysis stands, but as regards the tdb: (thing-described-by) system described in the above link.<\/p>\n
and I admit I’ve not got the 10 years of literature review as some of the community, but can’t we just do:<\/p>\n
infra:http:\/\/www.ecs.soton.ac.uk\/person\/cjg<\/p>\n
and specify that http:\/\/www.ecs.soton.ac.uk\/person\/cjg is assumed to be a document about that thing, and it could optionally content-negotiate if it wants.<\/p>\n
Effectively, there’s a standing definiation that <XYZ> foaf:primaryTopic <infra:XYZ> .<\/p>\n
NOTE: My first draft used “resource:” not “infra:” but that was very muddling to type in an RDF+XML document. I don’t really care about the choice of name, just the approach.<\/p>\n
Pros:<\/h3>\n