Viewing file: REGEXMatching.py (5.65 KB) -rw-r--r-- Select action/file-type: (+) | (+) | (+) | Code (+) | Session (+) | (+) | SDB (+) | (+) | (+) | (+) | (+) | (+) |
""" This wrapper intercepts calls through the store interface which make use of The REGEXTerm class to represent matches by REGEX instead of literal comparison Implemented for stores that don't support this and essentially provides the support by replacing the REGEXTerms by wildcards (None) and matching against the results from the store it's wrapping """
from rdflib.store import Store from pprint import pprint from rdflib.Graph import Graph, QuotedGraph, ConjunctiveGraph, BackwardCompatGraph import re
#Store is capable of doing it's own REGEX matching NATIVE_REGEX = 0 #Store uses python's re module internally for REGEX matching (SQLite for instance) PYTHON_REGEX = 1
#REGEXTerm can be used in any term slot and is interpreted as #a request to perform a REGEX match (not a string comparison) using the value #(pre-compiled) for checkin rdf:type matches class REGEXTerm(unicode): def __init__(self,expr): self.compiledExpr = re.compile(expr)
def __reduce__(self): return (REGEXTerm, (unicode(''),))
def regexCompareQuad(quad,regexQuad): for index in range(4): if isinstance(regexQuad[index],REGEXTerm) and not regexQuad[index].compiledExpr.match(quad[index]): return False return True
class REGEXMatching(Store): def __init__(self, storage): self.storage = storage self.context_aware = storage.context_aware #NOTE: this store can't be formula_aware as it doesn't have enough info to reverse #The removal of a quoted statement self.formula_aware = storage.formula_aware self.transaction_aware = storage.transaction_aware
def open(self, configuration, create=True): return self.storage.open(configuration,create)
def close(self, commit_pending_transaction=False): self.storage.close()
def destroy(self, configuration): self.storage.destroy(configuration)
def add(self, (subject, predicate, object_), context, quoted=False): self.storage.add((subject, predicate, object_), context, quoted)
def remove(self, (subject, predicate, object_), context=None): if isinstance(subject,REGEXTerm) or \ isinstance(predicate,REGEXTerm) or \ isinstance(object_,REGEXTerm) or \ (context is not None and isinstance(context.identifier,REGEXTerm)): #One or more of the terms is a REGEX expression, so we must replace it / them with wildcard(s) #and match after we query s = not isinstance(subject,REGEXTerm) and subject or None p = not isinstance(predicate,REGEXTerm) and predicate or None o = not isinstance(object_,REGEXTerm) and object_ or None c = (context is not None and not isinstance(context.identifier,REGEXTerm)) and context or None
removeQuadList = [] for (s1,p1,o1),cg in self.storage.triples((s,p,o),c): for ctx in cg: ctx = ctx.identifier if regexCompareQuad((s1,p1,o1,ctx),(subject,predicate,object_,context is not None and context.identifier or context)): removeQuadList.append((s1,p1,o1,ctx)) for s,p,o,c in removeQuadList: self.storage.remove((s,p,o),c and Graph(self,c) or c) else: self.storage.remove((subject,predicate,object_),context)
def triples(self, (subject, predicate, object_), context=None): if isinstance(subject,REGEXTerm) or \ isinstance(predicate,REGEXTerm) or \ isinstance(object_,REGEXTerm) or \ (context is not None and isinstance(context.identifier,REGEXTerm)): #One or more of the terms is a REGEX expression, so we must replace it / them with wildcard(s) #and match after we query s = not isinstance(subject,REGEXTerm) and subject or None p = not isinstance(predicate,REGEXTerm) and predicate or None o = not isinstance(object_,REGEXTerm) and object_ or None c = (context is not None and not isinstance(context.identifier,REGEXTerm)) and context or None for (s1,p1,o1),cg in self.storage.triples((s,p,o),c): matchingCtxs = [] for ctx in cg: if c is None: if context is None or context.identifier.compiledExpr.match(ctx.identifier): matchingCtxs.append(ctx) else: matchingCtxs.append(ctx) if matchingCtxs and regexCompareQuad((s1,p1,o1,None),(subject,predicate,object_,None)): yield (s1,p1,o1),(c for c in matchingCtxs) else: for (s1,p1,o1),cg in self.storage.triples((subject, predicate, object_), context): yield (s1,p1,o1),cg
def __len__(self, context=None): #NOTE: If the context is a REGEX this could be an expensive proposition return self.storage.__len__(context)
def contexts(self, triple=None): #NOTE: There is no way to control REGEX matching for this method at this level #(as it only returns the contexts, not the matching triples for ctx in self.storage.contexts(triple): yield ctx
def remove_context(self, identifier): self.storage.remove((None,None,None),identifier)
def bind(self, prefix, namespace): self.storage.bind(prefix, namespace)
def prefix(self, namespace): return self.storage.prefix(namespace)
def namespace(self, prefix): return self.storage.namespace(prefix)
def namespaces(self): return self.storage.namespaces()
def commit(self): self.storage.commit()
def rollback(self): self.storage.rollback()
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