SPARQL SERVICE with protected endpoint

Question

I need to use a protected endpoint to formulate a federated query in SPARQL like:

select ?s ?p ?o
{
 SERVICE <https://mysqparlendpoint/sparql/> {
   select ?s ?p ?o {
      ?s ?p ?o
   } limit 10
 }
}

Unfortunately in the SERVICE spec there is no hint how to do that. https://mysqparlendpoint/sparql is supposed to be a blazegraph on a tomcat, whose access is Basic secured.

How can I formulate this SPARQL query accessing the endpoint using credentials to open it?

Thanks a lot in advance!

Answer 1

SPARQL 1.1 Federation does not specify any way to authenticate.

Vendor-specific solutions:

• Blazegraph allows the usual notation user:password@server:port as explained above
• Ontotext GraphDB has internal federation that works across two password-protected repos on the same GraphDB instance

I've posted a SPARQL 1.2 issue: https://github.com/w3c/sparql-12/issues/117