Federated query from Allegrograph fails - unsupported MIME type

[irinafilitovich]

When running a federated query in Allegrograph 8.0.1 query interface:
SELECT * WHERE { SERVICE <https://qlever.cs.uni-freiburg.de/api/uniprot> { ?p a <http://purl.uniprot.org/core/Protein> ; rdfs:label "ABC transporter permease" . } } LIMIT 1
Getting:
QUERY FAILED: Canceling query because a SERVICE clause failed.
The original error was 'Remote SPARQL endpoint https://qlever.cs.uni-freiburg.de/api/uniprot returned unsupported MIME type: "application/json". The accepted types are: "application/x-ag-binary-rdf".'

While the same federated query with uniprot sparql endpoint returns a result:
SELECT * WHERE { SERVICE <https://sparql.uniprot.org/sparql> { ?p a <http://purl.uniprot.org/core/Protein> ; rdfs:label "ABC transporter permease" . } } LIMIT 1

[hannahbast]

@irinafilitovich There are two problems:

1. https://qlever.cs.uni-freiburg.de/api/uniprot is running with an older version of QLever, which indeed returns media type application/json instead of application/sparql-results+json when no media type is specified by the requester. In a few days, there will be an up-to-date version of this endpoint, and then this problem will be fixed.

2. The result of the SERVICE query is large (789,526 rows). The LIMIT 1 should be inside of the SERVICE call.

[irinafilitovich]

@hannahbast, thank you, I'll wait for the new version of the endpoint and try again.
The query isn't optimal, apologies for that, but that doesn't influence the issue being tested.