On Tue, Aug 30, 2011 at 10:45 AM, David Riccitelli <[email protected]> wrote: > 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?
Queries are not supported by "caches". (cache strategy "used") Only if you use local index (cache strategy "all") also queries are exceeded on the locally available data. You could simple go the the configuration tab of the Felix Web Console (http://localhost:8080/system/console/configMgr), open the configuration for the dbpedia Referenced Site and change the configuration of the CacheStrategy from "used" to "all". After that queries should be executed locally over the entities you have previously cached from dbpedia.org. best Rupert Westenthaler BTW: I forgot to mention in my last mail, that I am getting the exact same JSONExceptions as you mentioned. Caused by: 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! at org.apache.stanbol.entityhub.core.impl.ReferencedSiteImpl.findEntities(ReferencedSiteImpl.java:318) at org.apache.stanbol.enhancer.engines.entitytagging.impl.NamedEntityTaggingEngine.computeEntityRecommentations(NamedEntityTaggingEngine.java:408) at org.apache.stanbol.enhancer.engines.entitytagging.impl.NamedEntityTaggingEngine.computeEnhancements(NamedEntityTaggingEngine.java:320) ... 44 more Caused by: java.io.IOException: Unable to parse JSON Result Set for parsed query at org.apache.stanbol.entityhub.site.linkeddata.impl.SparqlSearcher.extractEntitiesFromJsonResult(SparqlSearcher.java:113) at org.apache.stanbol.entityhub.site.linkeddata.impl.VirtuosoSearcher.findEntities(VirtuosoSearcher.java:92) at org.apache.stanbol.entityhub.core.impl.ReferencedSiteImpl.findEntities(ReferencedSiteImpl.java:316) ... 46 more Caused by: org.codehaus.jettison.json.JSONException: A JSONObject text must begin with '{' at character 0 of at org.codehaus.jettison.json.JSONTokener.syntaxError(JSONTokener.java:439) at org.codehaus.jettison.json.JSONObject.<init>(JSONObject.java:169) at org.codehaus.jettison.json.JSONObject.<init>(JSONObject.java:266) at org.apache.stanbol.entityhub.site.linkeddata.impl.SparqlSearcher.extractEntitiesFromJsonResult(SparqlSearcher.java:87) ... 48 more > 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 > -- | Rupert Westenthaler [email protected] | Bodenlehenstraße 11 ++43-699-11108907 | A-5500 Bischofshofen
