def _remove_tp_filters(self, tp):
"""
Transforms a triple pattern that may contain filters to a new one with both subject and object bounded
to variables
:param tp: The triple pattern to be filtered
:return: Filtered triple pattern
"""
def __create_var(elm, predicate):
if elm in self._filter_mapping.values():
elm = list(filter(lambda x: self._filter_mapping[x] == elm, self._filter_mapping)).pop()
elif predicate(elm):
v = '?{}'.format(uuid())
self._filter_mapping[v] = elm
elm = v
return elm
s, p, o = tp_parts(tp)
s = __create_var(s, lambda x: '<' in x and '>' in x)
o = __create_var(o, lambda x: '"' in x or ('<' in x and '>' in x))
return '{} {} {}'.format(s, p, o)
def _query(fid, gp):
"""
Query the fragment using the original request graph pattern
:param gp:
:param fid:
:return: The query result
"""
def __build_query_from(x, depth=0):
def build_pattern_query((u, v, data)):
return '\nOPTIONAL { %s %s %s %s }' % (u, data['predicate'], v, __build_query_from(v, depth + 1))
out_edges = list(gp_graph.out_edges_iter(x, data=True))
out_edges = reversed(sorted(out_edges, key=lambda x: gp_graph.out_degree))
if out_edges:
return ' '.join([build_pattern_query(x) for x in out_edges])
return ''
gp_parts = [tp_parts(tp) for tp in gp]
blocks = []
gp_graph = nx.DiGraph()
for gp_part in gp_parts:
gp_graph.add_edge(gp_part[0], gp_part[2], predicate=gp_part[1])
roots = filter(lambda x: gp_graph.in_degree(x) == 0, gp_graph.nodes())
blocks += ['%s a stoa:Root\nOPTIONAL { %s }' % (root, __build_query_from(root)) for root in roots]
where_gp = ' .\n'.join(blocks)
q = """SELECT DISTINCT * WHERE { %s }""" % where_gp
result = []
try:
log.info('Querying fragment {}:\n{}'.format(fid, q))
result = fragment_graph(fid).query(q)
except Exception as e: # ParseException from query
traceback.print_exc()
log.warning(e.message)
return result
def graph_from_gp(gp):
gp_graph = nx.DiGraph()
gp_parts = [tp_parts(tp) for tp in gp]
for gp_part in gp_parts:
gp_graph.add_edge(gp_part[0], gp_part[2], predicate=gp_part[1])
return gp_graph
