Python SPARQL

This package provides parsers and serializers for the SPARQL 1.1 Query Language.

Note: This is not a SPARQL processing engine.

Install

Replace <version> with the latest GitHub release.

pip install https://github.com/Kurrawong/sparql/archive/refs/tags/<version>.zip

Usage

from sparql.parser import sparql_parser, sparql_update_parser
from sparql.serializer import SparqlSerializer

query = r'''
PREFIX : <http://www.example.org/>

INSERT DATA { 
              GRAPH<g1> { _:b1 :p :o } 
              GRAPH<g2> { _:b1 :p :o } 
            }

'''

# For SPARQL 1.1 Update, use sparql_update_parser
tree = sparql_parser.parse(query)

sparql_serializer = SparqlSerializer()
sparql_serializer.visit_topdown(tree)

print(query)
print(f"Tree: {tree}")
print(f"\nNew query:\n{sparql_serializer.result}")

new_tree = sparql_parser.parse(sparql_serializer.result)
print(f"\nQuery is the same: {tree == new_tree}")
assert tree == new_tree

Convenience Functions

Function sparql.format_string

For a given SPARQL query string, return a formatted SPARQL query string. This function by default will perform a guess on whether to use a SPARQL 1.1 parser or SPARQL 1.1 Update parser. Otherwise, a specific parser can be specified as a second argument.

import sparql

result = sparql.format_string(
    """
    select distinct ?s (count(?s) as ?count)
    FROM <http://dbpedia.org>
    FROM NAMED <http://dbpedia.org>
    where {
        ?s ?p ?o .
        ?o ?pp ?oo ;
            ?ppp ?ooo .
        OPTIONAL {
            ?s a ?o .
        } .
        ?o2 ?p2 ?o3 .
    }
"""
)

assert result

result = sparql.format_string(
    """
    LOAD <http://example.org/faraway> INTO GRAPH <localCopy>
"""
)

assert result

Conformance

The parser and serializer is passing all positive tests found online, examples from the specification, and also the tests from the https://github.com/w3c/rdf-tests repository.

One single test is marked as an xfail in the test_sparql_test_suite_from_rdf_tests.py test due to the limitation of the serializer's implementation. The serializer creates an output string by walking the AST in a recursive manner. In cases where a very large query is provided, this will hit the default Python recursion limit. Future updates to this package may refactor the code to convert its recursive serializer into an interative one.