Re: ask and you shall be redirected

On 24 Nov 2011, at 18:43, Peter Williams wrote:

> The current spec counsels implementors to use
> 
> PREFIX : <http://www.w3.org/ns/auth/cert#>
> ASK {
>    <https://bob.example/webid#public> :key [
>       :modulus "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"^^xsd:hexBinary;
>       :exponent 65537;
> 
>  
> I need help from folks who understand query semantics (and ideally secure query semantics).
>  
> I could pull the graph from the webid in the cert, and follow redirects., bob.example is redirected to bob.xxx. 

It is best to currently fetch directly using a good URL library.

I know we need to think about redirects more carefully, just to see if there are issues one should take care of. 
Perhaps there is a document on this somewhere that goes into details of how this works?

> Ive no idea if the identity of the graph in the local repository is titled with the webid, or the fourth redirect the webget library I've used just followed.

I think most of us have started working without redirects at all. I think we are sure about that situation.

> When  I issue the above query, with the webid  from the cert(bob.example)  against the local triple store (sourced to bob.xxx), will it match my graph? Assume my graph has no cert.identity (deprecated) and no foaf.name property.

that will totally depend on your triple store set up I think - but I may be wrong. In any case I would not rely on this being well defined yet.
Get a graph and work with the graph you found at the first GET.

>  
> Now, as I recall there was a variant, in which there was the likes of SELECT FROM <uri> (and presumably there is an ASK FROM <uri>.) 

If you have a local triple store that is set to fetch graphs from the web then yes. If you don't have that then no.
The spec is quite clear to ask you to dereference the graph. So 
>  
> Does it make any difference whether I webget a graph (following redirects) or use FROM? 
>  
> Can I assume that the handling of redirects and any fixups in the query as presented is specified in the query language design, when one uses the FROM option?
>  
> Which is more "appropirate" for the state of the web, today?

The query in the spec is one where the FROM is already known, because you fetched it.

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Social Web Architect
http://bblfish.net/