[foaf-dev] Redirects on FOAF vocabulary URIs

Tom Heath tom.heath at gmail.com
Thu Aug 16 18:17:34 BST 2007


Hi Andreas,

Both approaches are valid, although the DC implementation is incorrect
(see below).

Quoting the "How to Publish Linked Data..." tutorial...

"Non-Information Resources cannot be dereferenced directly. Therefore
Web architecture uses a trick to enable URIs identifying
non-information resources to be dereferenced: Instead of sending a
representation of the resource, the server sends the client the URI of
a information resource which describes the non-information resource
using the HTTP response code 303 See Other. This is called a 303
redirect. In a second step, the client dereferences this new URI and
gets a representation describing the original non-information
resource."
from 'Dereferencing HTTP URIs' under
<http://sites.wiwiss.fu-berlin.de/suhl/bizer/pub/LinkedDataTutorial/#Terminology>

So the information resource (e.g. http://xmlns.com/foaf/spec/) the
useragent is 303 redirected to simply needs to describe the original
non-information resource (e.g. http://xmlns.com/foaf/0.1/Person). It's
ok if the information resource also describes other things; therefore
both approaches are valid. Ideally both FOAF and DC would also do
content negotiation on term URIs and redirect to representations in
HTML or RDF/XML accordingly.

The reason why the DC implementation is broken is that it does HTTP
302 Moved Temporarily redirects rather than HTTP 303 See Other.

HTH :)

Tom.

On 16/08/07, Andreas Harth <andreas.harth at deri.org> wrote:
> Hi,
>
> I'm experimenting with redirection, and noticed that all FOAF URLs redirect
> to the same document, that is, without taking into account the "local name"
> of a URI.
>
> I.e.
> http://xmlns.com/foaf/0.1/Person -> http://xmlns.com/foaf/spec/
> http://xmlns.com/foaf/0.1/mbox -> http://xmlns.com/foaf/spec/
> and so on
>
> Is that desired behavior?
>
> DC seems to handle the redirect differently:
>
> http://purl.org/dc/elements/1.1/date ->
> http://dublincore.org/2006/12/18/dces.rdf#date
>
> Regards,
> Andreas.
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> foaf-dev at lists.foaf-project.org
> http://lists.foaf-project.org/mailman/listinfo/foaf-dev
>


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