Thanks Rupert, So for me it looks like that the dbpedia.org SPARQL server has > currently some problems in writing JSON responses.
According to you, if I would create an offline cache of DBpedia, would I be able to overcome this issue? BR David On Tue, Aug 30, 2011 at 11:39 AM, Rupert Westenthaler < [email protected]> wrote: > Hi David > > On Mon, Aug 29, 2011 at 4:40 PM, David Riccitelli > <[email protected]> wrote: > > Hi Rupert, > > > > I think is this one: > > > http://dbpedia.org/sparql?query=SELECT+DISTINCT+?id+%0AWHERE+%7B+%0A++%7B+%0A++++?id+%3Chttp://www.w3.org/1999/02/22-rdf-syntax-ns%23type%3E+%3Chttp://dbpedia.org/ontology/Person%3E+.+%0A++++?id+%3Chttp://www.w3.org/2000/01/rdf-schema%23label%3E+?tmp1+.+%0A++++++?tmp1+bif:contains+'%22Plantar%22'+.+%0A%7D+%0A%7D+%0AORDER+BY+DESC+(+%3CLONG::IRI_RANK%3E+(?id)+)+%0ALIMIT+20+%0A&format=application/sparql-results%2Bjson > > > > This corresponds to this SPARQL query: > > SELECT DISTINCT ?id > WHERE { > { > ?id <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> > <http://dbpedia.org/ontology/Person> . > ?id <http://www.w3.org/2000/01/rdf-schema#label> ?tmp1 . > ?tmp1 bif:contains '"Plantar"' . > } > } > ORDER BY DESC ( <LONG::IRI_RANK> (?id) ) > LIMIT 20 > > this is a typical query as used by the NamedEntityTaggingEngine to lookup > an Entity with the name "Plantar" for an TextAnnotation with the > dc:type dbpedia-ont:Person > > > In fact before that exception I have this one: > > > > 29.08.2011 08:51:54.939 *WARN* [1605442425@qtp-23480987-1] > > org.apache.felix.http.jetty /engines/ > > (org.apache.stanbol.enhancer.servicesapi.EngineException: > > 'NamedEntityTaggingEngine' failed to process content item > > 'urn:content-item-sha1-feef2e6a8bb37b08ff71e7b2d27582ae4c640adb' with > type > > 'text/plain': > > org.apache.stanbol.entityhub.servicesapi.site.ReferencedSiteException: > > Unable to execute query on remote site http://dbpedia.org/sparql with > > entitySearcher org.apache.stanbol.entityhub.searcher.VirtuosoSearcher!) > > org.apache.stanbol.enhancer.servicesapi.EngineException: > > 'NamedEntityTaggingEngine' failed to process content item > > 'urn:content-item-sha1-feef2e6a8bb37b08ff71e7b2d27582ae4c640adb' with > type > > 'text/plain': > > org.apache.stanbol.entityhub.servicesapi.site.ReferencedSiteException: > > Unable to execute query on remote site http://dbpedia.org/sparql with > > entitySearcher org.apache.stanbol.entityhub.searcher.VirtuosoSearcher! > > (...) > > Caused by: java.io.IOException: Server returned HTTP response code: 500 > for > > URL: > > > http://dbpedia.org/sparql?query=SELECT+DISTINCT+?id+%0AWHERE+%7B+%0A++%7B+%0A++++?id+%3Chttp://www.w3.org/1999/02/22-rdf-syntax-ns%23type%3E+%3Chttp://dbpedia.org/ontology/Person%3E+.+%0A++++?id+%3Chttp://www.w3.org/2000/01/rdf-schema%23label%3E+?tmp1+.+%0A++++++?tmp1+bif:contains+'%22Plantar%22'+.+%0A%7D+%0A%7D+%0AORDER+BY+DESC+(+%3CLONG::IRI_RANK%3E+(?id)+)+%0ALIMIT+20+%0A&format=application/sparql-results%2Bjson > > (...) > > > In the earlier mail you where getting a JSONException while praising > the response of a query. Here you are getting a 500 indicating the the > dbpedia SPARQL endpoint had some problems. > > Testing this query today resulted in a 200. However I could observe > strange behavior while testing. > Precisely: sending the above URL with curl -v printed the headers of > the response however after that the curl command has not terminated as > expected. It kept running until I manually terminated it. > Making the same request but without the > "&format=application/sparql-results%2Bjson" parameter I was also > getting a 200 (as expected) but this time curl terminated and printed > > <sparql xmlns="http://www.w3.org/2005/sparql-results#"; > xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; > xsi:schemaLocation="http://www.w3.org/2001/sw/DataAccess/rf1/result2.xsd";> > <head> > <variable name="id"/> > </head> > <results distinct="false" ordered="true"> > </results> > </sparql> > > ... an empty response. > > If I make a request with the above URL (including the > "&format=application/sparql-results%2Bjson") directly in the Browser I > get an empty response. As far as I know this would not be valid JSON > and could explain the JSONException as mentioned in the earlier mail. > > So for me it looks like that the dbpedia.org SPARQL server has > currently some problems in writing JSON responses. > > On Mon, Aug 29, 2011 at 4:51 PM, David Riccitelli > <[email protected]> wrote: > > If I run, $ curl " > > > http://dbpedia.org/sparql?query=SELECT+DISTINCT+?id+%ntax-ns%23type%3E+%3Chttp://dbpedia.org/ontology/Person%3E+.+%0A++++?id+%3Chttp://www.w3.org/2000/01/rdf-schema%23label%3E+?tmp1+.+%0A++++++?tmp1+bif:contains+'%22Plantar%22'+.+%0A%7D+%0A%7D+%0AORDER+BY+DESC+(+%3CLONG::IRI_RANK%3E+(?id)+)+%0ALIMIT+20+%0A&format=application/sparql-results%2Bjson > > " > > > > I get a: > > > > { "head": { "link": [], "vars": ["id"] }, > > "results": { "distinct": false, "ordered": true, "bindings": [ ] } } > > > I was not able to confirm this. The above URL is not an valid request > because > > SELECT+DISTINCT+?id+%ntax-ns%23type%3E+ > > "%ntax-ns" is not valid. Could it be that you have missed some parts > when copying this request to the mail? > > However the result noted in this mail would be the expected response > if the query would not return any results. > > On Mon, Aug 29, 2011 at 4:40 PM, David Riccitelli > <[email protected]> wrote: > > And then I have lots of these (at least 20): > > > > 29.08.2011 08:53:35.924 *INFO* [1605442425@qtp-23480987-1] > > org.apache.stanbol.enhancer.servicesapi.helper.EnhancementEngineHelper No > > Triple found for <urn:enhancement-fa2cfb8d-5cad-5e80-ea03-b2b39be6f404> > and > > property <http://purl.org/dc/terms/type>! -> return null > > 29.08.2011 08:53:35.924 *WARN* [1605442425@qtp-23480987-1] > > > org.apache.stanbol.enhancer.engines.entitytagging.impl.NamedEntityTaggingEngine > > Unable to process TextAnnotation > > <urn:enhancement-fa2cfb8d-5cad-5e80-ea03-b2b39be6f404> because property< > > http://purl.org/dc/terms/type> is not present > > > > Before processing TextAnnotations the NamedEntityTaggingEngine checks > that the "dc:type" and "selected-text" properties are present for an > TextAnnotations. So if you see such warnings there must be some other > enhancement engine present that creates TextAnnotations that are > missing the "dc:type" property. > > best > Rupert Westenthaler > > > -- > | Rupert Westenthaler [email protected] > | Bodenlehenstraße 11 ++43-699-11108907 > | A-5500 Bischofshofen > -- David Riccitelli ----- Skype: ziodave Twitter: @ziodave LinkedIn: http://it.linkedin.com/in/riccitelli ----- Interact SpA Via A. Bargoni 78 (scala F) 00153 Roma T +39 06 58318 301 F +39 06 58318 303
