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List:       nepomuk
Subject:    Re: [Nepomuk] Query for resource for exactly one known file
From:       Sebastian_Trüg <sebastian () trueg ! de>
Date:       2012-08-10 18:02:33
Message-ID: 50254CB9.8050500 () trueg ! de
[Download RAW message or body]

well, getting one resource from the URL you can just use 
Nepomuk2::Resource like so:

Nepomuk2::Resource res(url);

and you have your resource.

res.uri()

will get you the resource URI.

On 08/10/2012 05:55 PM, Dean Perry wrote:
> Hi all, more noob questions:
> 
> I'm trying to write something that will retrieve the resource for
> exactly one file for which I have the URL from a drag and drop
> operation... I'm using the Nepomuk::Query stuff because, to be honest, I
> can't make head nor tails of SPARQL yet.
> 
> So for starters:
> 
> - I know that I have a valid URL for a file
> 
> - I know its is in the database and
> 
> - using NepSAK I know that the resource has both NFO::fileName and
> NIE::url associated.
> 
> I was thinking that NIE::url would be the thing to compare against:
> 
> QString urlstring = url.toString();
> 
> Nepomuk::Query::ComparisonTerm term (
> 
> Nepomuk::Vocabulary::NIE::url(),
> 
> Nepomuk::Query::LiteralTerm ( urlstring ),
> 
> Nepomuk::Query::ComparisonTerm::Equal
> 
> );
> 
> But this doesn't return any results, even when I know for certain that
> the file has a resource with the NIE::url property that has the value
> I'm looking for. Changing 'Equal' to 'Contains' doesn't work either.
> 
> Using NFO::fileName works fine, but returns several results if there's a
> duplicate in the file system:
> 
> QString filename = urlstring.right ( ( urlstring.length() -
> urlstring.lastIndexOf ( '/' ) )-1 ); // yeah, ugly...
> 
> Nepomuk::Query::ComparisonTerm term(
> 
> Nepomuk::Vocabulary::NFO::fileName(),
> 
> Nepomuk::Query::LiteralTerm(filename),
> 
> Nepomuk::Query::ComparisonTerm::Contains
> 
> );
> 
> Using the FileQuery class does not help (but adds some constraints to
> the SPARQL).
> 
> I've also tried to use just the filename and 'Contains' against
> NIE::url, and that doesn't work either.
> 
> As I said, I'm pretty clueless with SPARQL, but when I take the Query
> generated SPARQL and paste into NepSAK the results are the same
> (obvious) but when I replace the nfo::fileName with nie::url it also
> doesn't work which is not very obvious to me eg:
> 
> select distinct ?r , ?v1 as ?_n_f_t_m_ex_ where { ?r nie:url ?v1 .
> FILTER(bif:contains(?v1,
> "'095262r00ZB_zigbee_rf4ce_sc-ZigBee_RF4CE_Specification_public.pdf'"))
> . FILTER EXISTS { ?r a [ nao:userVisible "true"^^XMLSchema:boolean ] . }
> . } LIMIT 20
> 
> I'm guessing I'm missing something obvious here...
> 
> cheers,
> 
> dean
> 
> Oh and secondary questions:
> 
> (1) the generated query has the stuff between ?r and ?v1 which seems
> extraneous and seems to return a result with HTML markup (<b></b> tags)
> that disappear if I remove them:
> 
> select distinct ?r
> (bif:concat(bif:search_excerpt(bif:vector('095262r00ZB_zigbee_rf4ce_sc-ZigBee_RF4CE_Specification_public.pdf'),
>  ?v1))) ....
> 
> vs
> 
> select distinct ?r, ?v1 ....
> 
> produces
> 
> <b>095262r00ZB</b> zigbee rf4ce sc ZigBee RF4CE Specification public.
> 
> vs
> 
> 095262r00ZB_zigbee_rf4ce_sc-ZigBee_RF4CE_Specification_public.pdf
> 
> (2) is it just me or does the 'bool' parameter for
> QueryServiceClient::syncQuery always return 'false' ?
> 
> 
> 
> _______________________________________________
> Nepomuk mailing list
> Nepomuk@kde.org
> https://mail.kde.org/mailman/listinfo/nepomuk
> 
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