CySparql

CySparql is a python wrapper over the excellent heavy-duty C Rasqal RDF v0.9.33+ SPARQL parser. The library is intended to give a pythonic feel to parsing SPARQL queries. There are several goodies included as well like:

• simple and fast star-pattern extraction from SPARQL queries
• node-edge (graph) visualizations of SPARQL queries
• simple descriptive command line utility to describe a given SPARQL query (from a file or read from stdin)
• auto pretty formatter for SPARQL queries (slower, than just parsing)

Important Notes

This software is the product of research carried out at the University of Zurich and comes with no warranty whatsoever. Have fun!

TODO's

• The librasqal is not fully supported (e.g. filters, etc)
• The project is not documented (yet)

How to Compile the Project

Ensure that librasqal v0.9.33+ and libraptor2 v2.0.13+ are installed on your system (either using the package manager of the OS or compiled from source).

To install CySparql you have two options: 1) manual installation (install requirements first) or 2) automatic with pip

Manual installation:

$ git clone https://github.com/cosminbasca/cysparql
$ cd cysparql
$ python setup.py install

Install the project with pip:

$ pip install https://github.com/cosminbasca/cysparql

Also have a look at the build.sh, clean.sh, test.sh scripts included in the codebase

Basic Example

from cysparql import *
q_string = """
PREFIX example: <http://www.example.org/rdf#>
SELECT * WHERE {
    ?a example:p ?b1.
    ?a example:p ?b2.
    ?a example:p ?b3.
    ?a example:p ?b4.
    ?a example:p ?b5.
    ?a example:p ?b6.
    ?a example:q ?b6.
    ?b5 example:p ?x .
    ?b6 example:p ?y .
}
"""

query = Query(q_string, pretty=True)
# should print:
#[[ 0.  0.  0.  0.  1.  0.  0.  0.  0.]
# [ 0.  0.  0.  0.  0.  1.  0.  0.  0.]
# [ 0.  0.  0.  1.  1.  1.  1.  1.  1.]
# [ 0.  0.  1.  0.  0.  0.  0.  0.  0.]
# [ 1.  0.  1.  0.  0.  0.  0.  0.  0.]
# [ 0.  1.  1.  0.  0.  0.  0.  0.  0.]
# [ 0.  0.  1.  0.  0.  0.  0.  0.  0.]
# [ 0.  0.  1.  0.  0.  0.  0.  0.  0.]
# [ 0.  0.  1.  0.  0.  0.  0.  0.  0.]]
print query.adjacency_matrix

# sould print: triple_patterns =  <cysparql.pattern.TriplePatternSequence object at 0x1049a4730>
print 'triple_patterns = ',query.triple_patterns

# should print:
#STAR (0): 
# [< ?a, http://www.example.org/rdf#p, ?b1 ,None>, < ?a, http://www.example.org/rdf#p, ?b2 ,None>, < ?a, http://www.example.org/rdf#p, ?b3 ,None>, < ?a, http://www.example.org/rdf#p, ?b4 ,None>, < ?a, http://www.example.org/rdf#p, ?b5 ,None>, < ?a, http://www.example.org/rdf#p, ?b6 ,None>, < ?a, http://www.example.org/rdf#q, ?b6 ,None>]
#
#STAR (1): 
# [< ?a, http://www.example.org/rdf#p, ?b5 ,None>, < ?b5, http://www.example.org/rdf#p, ?x ,None>]
#
#STAR (2): 
# [< ?a, http://www.example.org/rdf#p, ?b6 ,None>, < ?a, http://www.example.org/rdf#q, ?b6 ,None>, < ?b6, http://www.example.org/rdf#p, ?y ,None>]
stars = get_stars(query.triple_patterns)
for i,s in enumerate(stars):
    print '\nSTAR (%s): \n %s'%(i,s)

# if asciinet is installed
# should print:
#ASCII: 
#          ┌─────────────┐           
#          │     ?a      │           
#          └┬┬──┬─────┬┬┬┘           
#           ││  │     │││            
#           ││  │     ││└───┐        
#    ┌──────┼┘  │     ││    │        
#    │      │   │     ││    │        
#    v      v   │     ││    │        
#  ┌───┐  ┌───┐ │     ││    │        
#  │?b6│  │?b5│ │     ││    │        
#  └┬──┘  └─┬─┘ │     ││    │        
#   │       │   │     ││    │        
#   │     ┌─┘   │     │└────┼─────┐  
#   │     │     │     │     │     │  
#   v     v     v     v     v     v  
# ┌───┐ ┌───┐ ┌───┐ ┌───┐ ┌───┐ ┌───┐
# │?y │ │?x │ │?b3│ │?b2│ │?b1│ │?b4│
# └───┘ └───┘ └───┘ └───┘ └───┘ └───┘
print 'ASCII: \n',query.ascii

# print the librasqal debug information
# should print:
#query verb: SELECT
#data graphs: []
#named variables: [variable(a), variable(b1), variable(b2), variable(b3), variable(b4), variable(b5), variable(b6), variable(x), variable(y)]
#anonymous variables: []
#projected variable names: a, b1, b2, b3, b4, b5, b6, x, y
#
#bound variables: [variable(a), variable(b1), variable(b2), variable(b3), variable(b4), variable(b5), variable(b6), variable(x), variable(y)]
#triples: [triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b1)), triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b2)), triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b3)), triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b4)), triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b5)), triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b6)), triple(variable(a), uri<http://www.example.org/rdf#q>, variable(b6)), triple(variable(b5), uri<http://www.example.org/rdf#p>, variable(x)), triple(variable(b6), uri<http://www.example.org/rdf#p>, variable(y))]
#prefixes: [prefix(example as http://www.example.org/rdf#)]
#query graph pattern: graph pattern[0] Basic(over 9 triples[triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b1)) ,triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b2)) ,triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b3)) ,triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b4)) ,triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b5)) ,triple(variable(a), uri<http://www.example.org/rdf#p>, variable(b6)) ,triple(variable(a), uri<http://www.example.org/rdf#q>, variable(b6)) ,triple(variable(b5), uri<http://www.example.org/rdf#p>, variable(x)) ,triple(variable(b6), uri<http://www.example.org/rdf#p>, variable(y))])
query.debug()

Thanks a lot to

• University of Zurich and the Swiss National Science Foundation for generously funding the research that led to this software.