Source code for rdflib.plugins.serializers.trig

"""
Trig RDF graph serializer for RDFLib.
See <http://www.w3.org/TR/trig/> for syntax specification.
"""

from collections import defaultdict

from rdflib.plugins.serializers.turtle import TurtleSerializer, _GEN_QNAME_FOR_DT, VERB

from rdflib.term import BNode, Literal

__all__ = ['TrigSerializer']


[docs]class TrigSerializer(TurtleSerializer): short_name = "trig" indentString = 4 * u' '
[docs] def __init__(self, store): if store.context_aware: self.contexts = store.contexts() else: self.contexts = [store] super(TrigSerializer, self).__init__(store)
[docs] def preprocess(self): for context in self.contexts: self.store = context self._references = defaultdict(int) self._subjects = {} for triple in context: self.preprocessTriple(triple) self._contexts[context]=(self.orderSubjects(), self._subjects, self._references)
[docs] def preprocessTriple(self, triple): s, p, o = triple self._references[o]+=1 self._subjects[s] = True for i, node in enumerate(triple): if node in self.keywords: continue # Don't use generated prefixes for subjects and objects self.getQName(node, gen_prefix=(i == VERB)) if isinstance(node, Literal) and node.datatype: self.getQName(node.datatype, gen_prefix=_GEN_QNAME_FOR_DT) p = triple[1] if isinstance(p, BNode): self._references[p]+=1
[docs] def reset(self): super(TrigSerializer, self).reset() self._contexts = {}
[docs] def serialize(self, stream, base=None, encoding=None, spacious=None, **args): self.reset() self.stream = stream self.base = base if spacious is not None: self._spacious = spacious self.preprocess() self.startDocument() firstTime = True for store, (ordered_subjects, subjects, ref) in self._contexts.items(): self._references = ref self._serialized = {} self.store = store self._subjects = subjects self.write(self.indent() + '\n<%s> = {' % self.getQName(store.identifier)) self.depth += 1 for subject in ordered_subjects: if self.isDone(subject): continue if firstTime: firstTime = False if self.statement(subject) and not firstTime: self.write('\n') self.depth -= 1 self.write('}\n') self.endDocument() stream.write(u"\n".encode('ascii'))