[SOLVED] HTTP Error 414 with query to DBPedia endpoint using SPARQLwrapper

HTTP Error 414 with query to DBPedia endpoint using SPARQLwrapper

I made a function that executes a SPARQL query on the DBpedia SPARQL endpoint. This function takes an array of 15 elements, and each time it substitutes an element from the array into the query, then executes it to get result. The problem is that it takes the first 9 elements then this error is raised:

results = sparql.query().convert()
  File "build/bdist.linux-i686/egg/SPARQLWrapper/Wrapper.py", line 390, in query
    return QueryResult(self._query())
  File "build/bdist.linux-i686/egg/SPARQLWrapper/Wrapper.py", line 369, in _query
    raise e
HTTPError: HTTP Error 414: Request-URI Too Large

My query is as follows:

sparql = SPARQLWrapper('http://mlode.nlp2rdf.org/sparql');
querystring="""
PREFIX  dc:<http://purl.org/dc/elements/1.1/>
PREFIX  foaf: <http://xmlns.com/foaf/0.1/>
PREFIX  olia-ar: <http://purl.org/olia/arabic_khoja.owl#>
PREFIX  dcterms: <http://purl.org/dc/terms/>
PREFIX  rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX  owl:  <http://www.w3.org/2002/07/owl#>
PREFIX  xsd:  <http://www.w3.org/2001/XMLSchema#>
PREFIX  lexvo: <http://lexvo.org/id/iso639-3/>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX  gold: <http://purl.org/linguistics/gold/>
PREFIX  skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX  qvoc: <http://www.nlp2rdf.org/quranvocab#>
SELECT  ?verseTextAr ?tafseer 
WHERE
  {
    ?verse a qvoc:Verse;
     qvoc:chapterIndex 26;
     qvoc:verseIndex  WORD;
     skos:prefLabel ?verseTextAr;
      qvoc:descByJalalayn ?tafseer.
  }
  """

Solution

The 414 error means that SPARQLWrapper is trying to do a HTTP GET for the query but the query is too large resulting in a request URI that the DBPedia servers reject.

You need to get SPARQLWrapper to POST the query instead, the documentation states that this is possible and it appears that the setMethod() method should be used to configure this.