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ad-freiburg / qlever

Very fast SPARQL Engine, which can handle very large knowledge graphs like the complete Wikidata, offers context-sensitive autocompletion for SPARQL queries, and allows combination with text search. It's faster than engines like Blazegraph or Virtuoso, especially for queries involving large result sets.
Apache License 2.0
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SERVICE response check is not sufficiently flexible (regression) #1489

Closed ahankinson closed 2 weeks ago

ahankinson commented 2 weeks ago

In this commit by @UNEXENU:

https://github.com/ad-freiburg/qlever/commit/87e33299c49acdd1221f8ae12b9cecb30c58b5eb

The media type response of a SERVICE response was specified, and it now raises an exception on a query that does not match.

However, some services (Wikipedia, https://query.wikidata.org/sparql) can return a media type like this:

application/sparql-results+json;charset=utf-8

This is correct, except that the charset specifier is also included, which is allowed. The result is the SERVICE query fails:

Error while executing a SERVICE request to <https://query.wikidata.org:443/sparql>: QLever requires the endpoint of a SERVICE to send the result as 'application/sparql-results+json' but the endpoint sent 'application/sparql-results+json;charset=utf-8'.

So the new check for the media type of the response is not sufficiently flexible to allow for additional fields in the response type. This is a regression, since our SERVICE query used to work but now it raises an exception.

UNEXENU commented 2 weeks ago

Thank you for reporting this issue.

It seems like i was unaware of the potential existence of parameters in content-types, which lead to this bug.

1490 should fix this / allow parameters in the content-type again.