I am running bigdata 2.1.5 on a tomcat on a OSX system. This is giving a /bigdata/ URI which shows up a running html console of Blazegraph. This bigdata instance "DBPedia" is using a journal with DBPedia triples inside. DBPedia is showing up to the console, triples are queryable.
When I use from - say - https://query.wikidata.org/ - that bigdata instance by URI server/bigdata/namespace/DBPedia/sparql - that URI is not used, resp. the calling SPARQL engine throws an Exception that the service is not found.
Blazegraph has a page - https://wiki.blazegraph.com/wiki/index.php/FederatedQuery - where in a way it is described what to do in order to get federated querying running (although I want just to call my bigdata instance from outsite - this is also a federation) ... you should change (uncomment) a parametrization chunk inside bigdata's web.xml like
<context-param> <description>List of allowed services.</description> <param-name>serviceWhitelist</param-name> <param-value>http://www.bigdata.com/rdf/search#search,http://www.bigdata.com/rdf#describe</param-value> </context-param>
I changed that chunk but without success. Probably it is just to be able to call from that bigdata instance another service whose URI must be whitlisted. So I am stuck figuring out how to call my bigdata instance from - say wikidata - SPARQL engine...
Anyone an idea?
The problem arose inside the calling SPARQL engine I used. Not in Blazegraph. So you have to check whether the SPARQL Engine you are currently using allows to open that URL inside a SERVICE expression (whitelisting)!