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The SPARQLStore communicates with an external repository (triple-store) using the cURL method for transferring data from and to an endpoint.

A connection to an external endpoint can be severed caused by network lag or any other form of data loss. In those cases where the system (namely SMW) cannot make a judgement about how to handle that sort of error (e.g. connection issue as indicated by a HTTP/cURL response code), the SPARQStore will raise a HttpDatabaseConnectionException to indicate an erroneous event that was not resolvable.

For an analysis as to what went wrong HttpDatabaseConnectionException reports the error code, the endpoint, and a possible textual description of the error.

There are no additional information available besides what was reported by the HttpDatabaseConnectionException.


The example below identifies a communication issue with the Endpoint and needs to be fixed (externally).

Unexpected non-MediaWiki exception encountered, of type "SMW\SPARQLStore\Exception\HttpDatabaseConnectionException"
[ab6501bf] /mw-23-01/index.php/Property:Has_area Exception from line 63 of ...\src\SPARQLStore\BadHttpResponseMapper.php: Failed to communicate to Endpoint: due to curl error: 28 (Connection timed out after 10000 milliseconds).

Caused by

  • Network lag
  • Unresponsive server (could no respond to the request the SPARQLStore has made)
  • Time-out caused by an extended connection duration


Errors marked or raised as HttpDatabaseConnectionException are beyond the direct control of Semantic MediaWiki.

See also