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 typing import IO, TYPE_CHECKING, Optional, Union

from rdflib.graph import ConjunctiveGraph, Graph
from rdflib.plugins.serializers.turtle import TurtleSerializer
from rdflib.term import BNode, Node


__all__ = ["TrigSerializer"]


[docs]class TrigSerializer(TurtleSerializer): short_name = "trig" indentString = 4 * " "
[docs] def __init__(self, store: Union[Graph, ConjunctiveGraph]): self.default_context: Optional[Node] if store.context_aware: if TYPE_CHECKING: assert isinstance(store, ConjunctiveGraph) self.contexts = list(store.contexts()) self.default_context = store.default_context.identifier if store.default_context: self.contexts.append(store.default_context) else: self.contexts = [store] self.default_context = None super(TrigSerializer, self).__init__(store)
[docs] def preprocess(self): for context in self.contexts: self.store = context self.getQName(context.identifier) self._references = defaultdict(int) self._subjects = {} for triple in context: self.preprocessTriple(triple) self._contexts[context] = ( self.orderSubjects(), self._subjects, self._references, )
[docs] def reset(self): super(TrigSerializer, self).reset() self._contexts = {}
[docs] def serialize( self, stream: IO[bytes], base: Optional[str] = None, encoding: Optional[str] = None, spacious: Optional[bool] = None, **args, ): self.reset() self.stream = stream # if base is given here, use that, if not and a base is set for the graph use that if base is not None: self.base = base elif self.store.base is not None: self.base = self.store.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(): if not ordered_subjects: continue self._references = ref self._serialized = {} self.store = store self._subjects = subjects if self.default_context and store.identifier == self.default_context: self.write(self.indent() + "\n{") else: if isinstance(store.identifier, BNode): iri = store.identifier.n3() else: iri = self.getQName(store.identifier) if iri is None: iri = store.identifier.n3() self.write(self.indent() + "\n%s {" % iri) 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("\n".encode("latin-1"))