#!/usr/bin/env python
"""
RDF Utilities
License: GPL 2; share and enjoy!
Author: Sean B. Palmer, inamidst.com

Dependencies: 
   http://www.redland.opensource.ac.uk/
   Redland and Python Bindings
"""

import urllib
import RDF

class Graph(object): 
   def __init__(self, uri=None, storage=None): 
      self.model = RDF.Model(storage)
      if uri: 
         u = urllib.urlopen(uri)
         s = u.read()
         u.close()

         parser = RDF.Parser(name="rdfxml")
         for statement in parser.parse_string_as_stream(s, uri): 
            self.model.append(statement)

   def rdql(self, query): 
      q = RDF.Query(query)
      return q.execute(self.model)

def main(): 
   foaf = Graph("http://inamidst.com/proj/rdf/foaf")
   result = foaf.rdql("""SELECT ?name WHERE (?person foaf:name ?name) 
                         USING foaf FOR <http://xmlns.com/foaf/0.1/>""")
   print '\n'.join([str(res['name']) for res in result])

if __name__=="__main__": 
   main()