Problem with federated SPARQL query via Blazegraph - Wikidata

21 Feb 2017

Hi all,

I've found a 403 forbidden response with a SPARQL federated query. I simply
tested:

SELECT *
WHERE {
  service <https://query.wikidata.org/sparql> {
     ?s ?p ?o
  }
}
LIMIT 10

Using a Virtuoso endpoint like: https://contrattipubblici.org/sparql it
works fine!

But using a local Blazegraph instance it returns:

java.util.concurrent.ExecutionException:
java.util.concurrent.ExecutionException:
org.openrdf.query.QueryEvaluationException: java.lang.RuntimeException:
java.util.concurrent.ExecutionException: java.lang.RuntimeException:
java.util.concurrent.ExecutionException: java.lang.Exception:
task=ChunkTask{query=82b3f021-a8d3-447b-9aff-d4f10f72b80d,
bopId=1,partitionId=-1,sinkId=2,altSinkId=null},
cause=java.util.concurrent.ExecutionException:
java.util.concurrent.ExecutionException: java.lang.RuntimeException:
com.bigdata.rdf.sail.webapp.client.HttpException: Status Code=403, Status
Line=Forbidden, Response= 403 Forbidden 403 Forbidden nginx/1.11.6

Knowing that the Wikidata SPARQL service is built upon Blazegraph, could it
be a conflicting configuration of your nginx? Or do you have any other
suggestion?

Thanks,

Alessio