Allows using Oxigraph native serializers

oxrdflib/serializer.py

@@ -0,0 +1,63 @@
+from abc import ABC, abstractmethod
+from typing import IO, Any, Optional
+
+from pyoxigraph import RdfFormat, serialize
+from rdflib.serializer import Serializer
+
+from oxrdflib._converter import to_ox
+from oxrdflib.store import OxigraphStore
+
+__all__ = [
+    "OxigraphN3Serializer",
+    "OxigraphTurtleSerializer",
+    "OxigraphNTriplesSerializer",
+    "OxigraphRdfXmlSerializer",
+    "OxigraphTriGSerializer",
+    "OxigraphNQuadsSerializer",
+]
+
+
+class _OxigraphSerializer(Serializer, ABC):
+    def serialize(
+        self,
+        stream: IO[bytes],
+        _base: Optional[str] = None,
+        encoding: Optional[str] = None,
+        **kwargs: Any,  # noqa: ARG002
+    ) -> None:
+        if encoding not in (None, "utf-8"):
+            raise ValueError(f"RDF files are always utf-8 encoded, I was passed: {encoding}")
+        # TODO: base and prefixes
+        if isinstance(self.store, OxigraphStore):
+            self.store._inner.dump(stream, format=self._format)
+        else:
+            serialize((to_ox(q) for q in self.store), stream, format=self._format)
+
+    @property
+    @abstractmethod
+    def _format(self) -> RdfFormat:
+        pass
+
+
+class OxigraphN3Serializer(_OxigraphSerializer):
+    _format = RdfFormat.N3
+
+
+class OxigraphTurtleSerializer(_OxigraphSerializer):
+    _format = RdfFormat.TURTLE
+
+
+class OxigraphNTriplesSerializer(_OxigraphSerializer):
+    _format = RdfFormat.N_TRIPLES
+
+
+class OxigraphRdfXmlSerializer(_OxigraphSerializer):
+    _format = RdfFormat.RDF_XML
+
+
+class OxigraphNQuadsSerializer(_OxigraphSerializer):
+    _format = RdfFormat.N_QUADS
+
+
+class OxigraphTriGSerializer(_OxigraphSerializer):
+    _format = RdfFormat.TRIG

pyproject.toml

@@ -29,20 +29,29 @@ name = "oxrdflib"
 readme = "README.md"
 requires-python = ">=3.8"
 
-
 [project.entry-points."rdf.plugins.store"]
 Oxigraph = "oxrdflib.store:OxigraphStore"
+oxigraph = "oxrdflib.store:OxigraphStore"
 OxMemory = "oxrdflib.store:OxigraphStore"
 OxSled = "oxrdflib.store:OxigraphStore"
 
-
 [project.entry-points."rdf.plugins.parser"]
 ox-turtle = "oxrdflib.parser:OxigraphTurtleParser"
 ox-ttl = "oxrdflib.parser:OxigraphTurtleParser"
 ox-ntriples = "oxrdflib.parser:OxigraphNTriplesParser"
 ox-nt = "oxrdflib.parser:OxigraphNTriplesParser"
 ox-xml = "oxrdflib.parser:OxigraphRdfXmlParser"
 
+[project.entry-points."rdf.plugins.serializer"]
+ox-turtle = "oxrdflib.serializer:OxigraphTurtleSerializer"
+ox-ttl = "oxrdflib.serializer:OxigraphTurtleSerializer"
+ox-ntriples = "oxrdflib.serializer:OxigraphNTriplesSerializer"
+ox-n3 = "oxrdflib.serializer:OxigraphN3Serializer"
+ox-nquads = "oxrdflib.serializer:OxigraphNQuadsSerializer"
+ox-nt = "oxrdflib.serializer:OxigraphNTriplesSerializer"
+ox-nt11 = "oxrdflib.serializer:OxigraphNTriplesSerializer"
+ox-trig = "oxrdflib.serializer:OxigraphTriGSerializer"
+ox-xml = "oxrdflib.serializer:OxigraphRdfXmlSerializer"
 
 [project.urls]
 Changelog = "https://github.com/oxigraph/oxrdflib/blob/main/CHANGELOG.md"

tests/test_serializer.py

@@ -0,0 +1,60 @@
+import unittest
+
+from rdflib import Dataset, Graph, URIRef
+
+s = URIRef("http://example.com/s")
+p = URIRef("http://example.com/vocab#p")
+o = URIRef("http://example.com/o")
+g = URIRef("http://example.com/g")
+
+
+class TestSerializer(unittest.TestCase):
+    def test_serialize_graph(self):
+        for store in ("default", "oxigraph"):
+            for fmt, serialization in (
+                ("ox-turtle", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                ("ox-ttl", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                ("ox-ntriples", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                ("ox-n3", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                ("ox-nquads", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                ("ox-nt", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                ("ox-nt11", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                ("ox-trig", "<http://example.com/s> <http://example.com/vocab#p> <http://example.com/o> .\n"),
+                (
+                    "ox-xml",
+                    """<?xml version="1.0" encoding="UTF-8"?>
+<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
+	<rdf:Description rdf:about="http://example.com/s">
+		<s xmlns="http://example.com/vocab#" rdf:resource="http://example.com/o"/>
+	</rdf:Description>
+</rdf:RDF>""",
+                ),
+            ):
+                with self.subTest(store=store, format=fmt):
+                    graph = Graph(store=store)
+                    graph.add((s, p, o))
+                    graph.store.add((o, p, s), context=Graph(identifier=g))  # Should not be serialized
+                    self.assertEqual(graph.serialize(format=fmt), serialization)
+
+    def test_serialize_dataset(self):
+        for store in ("default", "oxigraph"):
+            for fmt, serialization in (
+                (
+                    "ox-nquads",
+                    "<http://example.com/s> <http://example.com/vocab#p> "
+                    "<http://example.com/o> <http://example.com/g> .\n",
+                ),
+                (
+                    "ox-trig",
+                    "<http://example.com/g> {\n\t<http://example.com/s> "
+                    "<http://example.com/vocab#p> <http://example.com/o> .\n}\n",
+                ),
+            ):
+                with self.subTest(store=store, format=fmt):
+                    dataset = Dataset(store=store)
+                    dataset.add((s, p, o, Graph(identifier=g)))
+                    self.assertEqual(dataset.serialize(format=fmt), serialization)
+
+
+if __name__ == "__main__":
+    unittest.main()