fix(distribution-probe): accept SPARQL results as JSON or XML#425
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A SELECT or ASK endpoint that answered in application/sparql-results+xml was wrongly classified as unreachable, because success required the response Content-Type to match the single Accept header we sent (application/sparql-results+json). A healthy endpoint then surfaced as a content-type violation and its body was never validated. SELECT/ASK probes now negotiate both serializations (Accept: application/sparql-results+json, application/sparql-results+xml;q=0.9) and treat either as success, validating the body with a lightweight structural check per serialization. This also aligns with publishers declaring SPARQL endpoints via dct:conformsTo rather than a media type.
ddeboer
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Jun 2, 2026
Brings in ldelements/lde#425: a SPARQL endpoint that answers a SELECT/ASK query in application/sparql-results+xml (not just +json) is now treated as reachable, fixing the spurious "HTTP 200 OK" content-type violation seen when validating SPARQL distributions. In-range bump (packages/core declares ^0.1.4), so only the lockfile changes.
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Problem
When probing a SPARQL endpoint,
SparqlProbeResult.isSuccess()required the responseContent-Typeto start with the singleAcceptheader we send for SELECT/ASK queries (application/sparql-results+json). An endpoint that answers inapplication/sparql-results+xml– a perfectly valid SPARQL Query Results serialization – was therefore classified as a failure even on an HTTP 200, and its body was never validated.Downstream (e.g. the Dataset Register), that healthy endpoint surfaced as a spurious content-type violation (“HTTP 200 OK”).
This also matters because publishers are asked to declare SPARQL endpoints via
dct:conformsTo, not a media type, so success must not hinge on a declared or negotiated serialization.Change
Accept: application/sparql-results+json, application/sparql-results+xml;q=0.9.SparqlProbeResultnow carriesacceptedContentTypes(a list). The constructor still accepts a singlestringand normalizes it, so existing consumers remain source-compatible.Tests
resultselement, XML ASK valid/invalid, non-SPARQL XML, the negotiatedAcceptheader, and single-string constructor normalization.@lde/distribution-probesuite passes (37 tests);pipelineanddistribution-monitortypecheck cleanly against the widened API.