Re: httpRange-14 Adjunct: 302 is Valid for Non-Information Resources

On Dec 4, 2007 5:29 PM, Richard Cyganiak <> wrote:

> Yes. But the vast majority of HTTP URIs are for traditional web
> pages, and those don't return any RDF. We are left to guess what
> they identify. Web pages? People? Things?

Well yes, but httpRange-14 doesn't fully resolve this. Here's an
enumeration of a Semantic Web use case that I had back in 2002, and
how httpRange-14 helps or not:

For the URI <>, the user wants to:

* Identify the tool Amaya; the URI returns a 200.

=> The user must use foaf:primaryTopic because the page is an
information resource per httpRange-14, and tools are disjoint with
information resources. [SUCCESS]

* Identify the tool Amaya; the URI returns a 303.

=> The user does not know what the URI identifies from resolving it
alone. httpRange-14 does not help. [FAIL]

* Identify the page as documentation about Amaya; the URI returns 200.

=> The user knows that this is information about Amaya by social
contract, and the HTTP response confirms that it is an information
resource per httpRange-14. [SUCCESS]

The fourth and final potential sub-use case of "Identify the page as
documentation about Amaya; the URI return 303" is probably not going
to happen, so this isn't a terribly good use case for discussing the
merits of httpRange-14.

But you can see that in general it only helps when the resource
returns a 200, because 303 doesn't mean <URI> a [ owl:complementOf
web:InformationResource ], it means <URI> a rdfs:Resource!

> httpRange-14 axiomatically declares that for all those URIs, the
> "naïve" interpretation is correct: They identify "the Google home
> page"; "Richard's homepage"; "the TAG blog"; and so on.

And you're saying that for the more irregular case of when a 303 is
returned, generally that question isn't going to be asked
anyway--especially if the page returns 303?

That does actually make some sense because in the use case above with
the [FAIL], "Identify the tool Amaya; the URI returns a 303", why is
the page returning a 303? Quite probably because it wants to identify
the tool Amaya and as a result it'll be giving you some 200'd RDF/XML
on the other side of the 303.

Are you *sure* that people won't end up having the same questions for
303'd resources? And does it matter even if they don't?

(Cf. the other thread I just started where I ask exactly the same
thing... I didn't expect these to converge within three emails!)

Sean B. Palmer,

Received on Tuesday, 4 December 2007 18:01:06 UTC