rdfxml.py 15 KB

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  1. from __future__ import annotations
  2. import xml.dom.minidom
  3. from typing import IO, Any, Dict, Generator, Optional, Set, Tuple
  4. from xml.sax.saxutils import escape, quoteattr
  5. from rdflib.collection import Collection
  6. from rdflib.graph import Graph
  7. from rdflib.namespace import RDF, RDFS, Namespace # , split_uri
  8. from rdflib.plugins.parsers.RDFVOC import RDFVOC
  9. from rdflib.plugins.serializers.xmlwriter import XMLWriter
  10. from rdflib.serializer import Serializer
  11. from rdflib.term import BNode, IdentifiedNode, Identifier, Literal, Node, URIRef
  12. from rdflib.util import first, more_than
  13. from .xmlwriter import ESCAPE_ENTITIES
  14. __all__ = ["fix", "XMLSerializer", "PrettyXMLSerializer"]
  15. class XMLSerializer(Serializer):
  16. """RDF/XML RDF graph serializer."""
  17. def __init__(self, store: Graph):
  18. super(XMLSerializer, self).__init__(store)
  19. def __bindings(self) -> Generator[Tuple[str, URIRef], None, None]:
  20. store = self.store
  21. nm = store.namespace_manager
  22. bindings: Dict[str, URIRef] = {}
  23. for predicate in set(store.predicates()):
  24. # type error: Argument 1 to "compute_qname_strict" of "NamespaceManager" has incompatible type "Node"; expected "str"
  25. prefix, namespace, name = nm.compute_qname_strict(predicate) # type: ignore[arg-type]
  26. bindings[prefix] = URIRef(namespace)
  27. RDFNS = URIRef("http://www.w3.org/1999/02/22-rdf-syntax-ns#") # noqa: N806
  28. if "rdf" in bindings:
  29. assert bindings["rdf"] == RDFNS
  30. else:
  31. bindings["rdf"] = RDFNS
  32. for prefix, namespace in bindings.items():
  33. yield prefix, namespace
  34. def serialize(
  35. self,
  36. stream: IO[bytes],
  37. base: Optional[str] = None,
  38. encoding: Optional[str] = None,
  39. **kwargs: Any,
  40. ) -> None:
  41. # if base is given here, use that, if not and a base is set for the graph use that
  42. if base is not None:
  43. self.base = base
  44. elif self.store.base is not None:
  45. self.base = self.store.base
  46. self.__stream = stream
  47. self.__serialized: Dict[Identifier, int] = {}
  48. encoding = self.encoding
  49. self.write = write = lambda uni: stream.write(uni.encode(encoding, "replace"))
  50. # startDocument
  51. write('<?xml version="1.0" encoding="%s"?>\n' % self.encoding)
  52. # startRDF
  53. write("<rdf:RDF\n")
  54. # If provided, write xml:base attribute for the RDF
  55. if "xml_base" in kwargs:
  56. write(' xml:base="%s"\n' % kwargs["xml_base"])
  57. elif self.base:
  58. write(' xml:base="%s"\n' % self.base)
  59. # TODO:
  60. # assert(
  61. # namespaces["http://www.w3.org/1999/02/22-rdf-syntax-ns#"]=='rdf')
  62. bindings = list(self.__bindings())
  63. bindings.sort()
  64. for prefix, namespace in bindings:
  65. if prefix:
  66. write(' xmlns:%s="%s"\n' % (prefix, namespace))
  67. else:
  68. write(' xmlns="%s"\n' % namespace)
  69. write(">\n")
  70. # write out triples by subject
  71. for subject in self.store.subjects():
  72. # type error: Argument 1 to "subject" of "XMLSerializer" has incompatible type "Node"; expected "Identifier"
  73. self.subject(subject, 1) # type: ignore[arg-type]
  74. # endRDF
  75. write("</rdf:RDF>\n")
  76. # Set to None so that the memory can get garbage collected.
  77. # self.__serialized = None
  78. del self.__serialized
  79. def subject(self, subject: Identifier, depth: int = 1) -> None:
  80. if subject not in self.__serialized:
  81. self.__serialized[subject] = 1
  82. if isinstance(subject, (BNode, URIRef)):
  83. write = self.write
  84. indent = " " * depth
  85. element_name = "rdf:Description"
  86. if isinstance(subject, BNode):
  87. write('%s<%s rdf:nodeID="%s"' % (indent, element_name, subject))
  88. else:
  89. uri = quoteattr(self.relativize(subject))
  90. write("%s<%s rdf:about=%s" % (indent, element_name, uri))
  91. if (subject, None, None) in self.store:
  92. write(">\n")
  93. for predicate, object in self.store.predicate_objects(subject):
  94. # type error: Argument 1 to "predicate" of "XMLSerializer" has incompatible type "Node"; expected "Identifier"
  95. # type error: Argument 2 to "predicate" of "XMLSerializer" has incompatible type "Node"; expected "Identifier"
  96. self.predicate(predicate, object, depth + 1) # type: ignore[arg-type]
  97. write("%s</%s>\n" % (indent, element_name))
  98. else:
  99. write("/>\n")
  100. def predicate(
  101. self, predicate: Identifier, object: Identifier, depth: int = 1
  102. ) -> None:
  103. write = self.write
  104. indent = " " * depth
  105. qname = self.store.namespace_manager.qname_strict(predicate)
  106. if isinstance(object, Literal):
  107. attributes = ""
  108. if object.language:
  109. attributes += ' xml:lang="%s"' % object.language
  110. if object.datatype:
  111. attributes += ' rdf:datatype="%s"' % object.datatype
  112. write(
  113. "%s<%s%s>%s</%s>\n"
  114. % (indent, qname, attributes, escape(object, ESCAPE_ENTITIES), qname)
  115. )
  116. else:
  117. if isinstance(object, BNode):
  118. write('%s<%s rdf:nodeID="%s"/>\n' % (indent, qname, object))
  119. else:
  120. write(
  121. "%s<%s rdf:resource=%s/>\n"
  122. % (indent, qname, quoteattr(self.relativize(object)))
  123. )
  124. XMLLANG = "http://www.w3.org/XML/1998/namespacelang"
  125. XMLBASE = "http://www.w3.org/XML/1998/namespacebase"
  126. OWL_NS = Namespace("http://www.w3.org/2002/07/owl#")
  127. # TODO:
  128. def fix(val: str) -> str:
  129. "strip off _: from nodeIDs... as they are not valid NCNames"
  130. if val.startswith("_:"):
  131. return val[2:]
  132. else:
  133. return val
  134. class PrettyXMLSerializer(Serializer):
  135. """Pretty RDF/XML RDF graph serializer."""
  136. def __init__(self, store: Graph, max_depth=3):
  137. super(PrettyXMLSerializer, self).__init__(store)
  138. self.forceRDFAbout: Set[URIRef] = set()
  139. def serialize(
  140. self,
  141. stream: IO[bytes],
  142. base: Optional[str] = None,
  143. encoding: Optional[str] = None,
  144. **kwargs: Any,
  145. ) -> None:
  146. self.__serialized: Dict[Identifier, int] = {}
  147. store = self.store
  148. # if base is given here, use that, if not and a base is set for the graph use that
  149. if base is not None:
  150. self.base = base
  151. elif store.base is not None:
  152. self.base = store.base
  153. self.max_depth = kwargs.get("max_depth", 3)
  154. assert self.max_depth > 0, "max_depth must be greater than 0"
  155. self.nm = nm = store.namespace_manager
  156. self.writer = writer = XMLWriter(stream, nm, encoding)
  157. namespaces = {}
  158. possible: Set[Node] = set(store.predicates()).union(
  159. store.objects(None, RDF.type)
  160. )
  161. for predicate in possible:
  162. # type error: Argument 1 to "compute_qname_strict" of "NamespaceManager" has incompatible type "Node"; expected "str"
  163. prefix, namespace, local = nm.compute_qname_strict(predicate) # type: ignore[arg-type]
  164. namespaces[prefix] = namespace
  165. namespaces["rdf"] = "http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  166. writer.push(RDFVOC.RDF)
  167. if "xml_base" in kwargs:
  168. writer.attribute(XMLBASE, kwargs["xml_base"])
  169. elif self.base:
  170. writer.attribute(XMLBASE, self.base)
  171. writer.namespaces(namespaces.items())
  172. subject: IdentifiedNode
  173. # Write out subjects that can not be inline
  174. # type error: Incompatible types in assignment (expression has type "Node", variable has type "IdentifiedNode")
  175. for subject in store.subjects(): # type: ignore[assignment]
  176. if (None, None, subject) in store:
  177. if (subject, None, subject) in store:
  178. self.subject(subject, 1)
  179. else:
  180. self.subject(subject, 1)
  181. # write out anything that has not yet been reached
  182. # write out BNodes last (to ensure they can be inlined where possible)
  183. bnodes = set()
  184. # type error: Incompatible types in assignment (expression has type "Node", variable has type "IdentifiedNode")
  185. for subject in store.subjects(): # type: ignore[assignment]
  186. if isinstance(subject, BNode):
  187. bnodes.add(subject)
  188. continue
  189. self.subject(subject, 1)
  190. # now serialize only those BNodes that have not been serialized yet
  191. for bnode in bnodes:
  192. if bnode not in self.__serialized:
  193. self.subject(subject, 1)
  194. writer.pop(RDFVOC.RDF)
  195. stream.write("\n".encode("latin-1"))
  196. # Set to None so that the memory can get garbage collected.
  197. self.__serialized = None # type: ignore[assignment]
  198. def subject(self, subject: Identifier, depth: int = 1):
  199. store = self.store
  200. writer = self.writer
  201. if subject in self.forceRDFAbout:
  202. writer.push(RDFVOC.Description)
  203. writer.attribute(RDFVOC.about, self.relativize(subject))
  204. writer.pop(RDFVOC.Description)
  205. self.forceRDFAbout.remove(subject) # type: ignore[arg-type]
  206. elif subject not in self.__serialized:
  207. self.__serialized[subject] = 1
  208. type = first(store.objects(subject, RDF.type))
  209. try:
  210. # type error: Argument 1 to "qname" of "NamespaceManager" has incompatible type "Optional[Node]"; expected "str"
  211. self.nm.qname(type) # type: ignore[arg-type]
  212. except Exception:
  213. type = None
  214. element = type or RDFVOC.Description
  215. # type error: Argument 1 to "push" of "XMLWriter" has incompatible type "Node"; expected "str"
  216. writer.push(element) # type: ignore[arg-type]
  217. if isinstance(subject, BNode):
  218. def subj_as_obj_more_than(ceil):
  219. return True
  220. # more_than(store.triples((None, None, subject)), ceil)
  221. # here we only include BNode labels if they are referenced
  222. # more than once (this reduces the use of redundant BNode
  223. # identifiers)
  224. if subj_as_obj_more_than(1):
  225. writer.attribute(RDFVOC.nodeID, fix(subject))
  226. else:
  227. writer.attribute(RDFVOC.about, self.relativize(subject))
  228. if (subject, None, None) in store:
  229. for predicate, object in store.predicate_objects(subject):
  230. if not (predicate == RDF.type and object == type):
  231. # type error: Argument 1 to "predicate" of "PrettyXMLSerializer" has incompatible type "Node"; expected "Identifier"
  232. # type error: Argument 2 to "predicate" of "PrettyXMLSerializer" has incompatible type "Node"; expected "Identifier"
  233. self.predicate(predicate, object, depth + 1) # type: ignore[arg-type]
  234. # type error: Argument 1 to "pop" of "XMLWriter" has incompatible type "Node"; expected "Optional[str]"
  235. writer.pop(element) # type: ignore[arg-type]
  236. elif subject in self.forceRDFAbout:
  237. # TODO FIXME?: this looks like a duplicate of first condition
  238. writer.push(RDFVOC.Description)
  239. writer.attribute(RDFVOC.about, self.relativize(subject))
  240. writer.pop(RDFVOC.Description)
  241. self.forceRDFAbout.remove(subject) # type: ignore[arg-type]
  242. def predicate(
  243. self, predicate: Identifier, object: Identifier, depth: int = 1
  244. ) -> None:
  245. writer = self.writer
  246. store = self.store
  247. writer.push(predicate)
  248. if isinstance(object, Literal):
  249. if object.language:
  250. writer.attribute(XMLLANG, object.language)
  251. if object.datatype == RDF.XMLLiteral and isinstance(
  252. object.value, xml.dom.minidom.Document
  253. ):
  254. writer.attribute(RDFVOC.parseType, "Literal")
  255. writer.text("")
  256. writer.stream.write(object)
  257. else:
  258. if object.datatype:
  259. writer.attribute(RDFVOC.datatype, object.datatype)
  260. writer.text(object)
  261. elif (
  262. object in self.__serialized
  263. or not (object, None, None) in store # noqa: E713
  264. ):
  265. if isinstance(object, BNode):
  266. if more_than(store.triples((None, None, object)), 0):
  267. writer.attribute(RDFVOC.nodeID, fix(object))
  268. else:
  269. writer.attribute(RDFVOC.resource, self.relativize(object))
  270. else:
  271. if first(store.objects(object, RDF.first)): # may not have type
  272. # RDF.List
  273. self.__serialized[object] = 1
  274. # Warn that any assertions on object other than
  275. # RDF.first and RDF.rest are ignored... including RDF.List
  276. import warnings
  277. warnings.warn(
  278. "Assertions on %s other than RDF.first " % repr(object)
  279. + "and RDF.rest are ignored ... including RDF.List",
  280. UserWarning,
  281. stacklevel=2,
  282. )
  283. writer.attribute(RDFVOC.parseType, "Collection")
  284. col = Collection(store, object)
  285. for item in col:
  286. if isinstance(item, URIRef):
  287. self.forceRDFAbout.add(item)
  288. # type error: Argument 1 to "subject" of "PrettyXMLSerializer" has incompatible type "Node"; expected "Identifier"
  289. self.subject(item) # type: ignore[arg-type]
  290. if not isinstance(item, URIRef):
  291. # type error: Invalid index type "Node" for "Dict[Identifier, int]"; expected type "Identifier"
  292. self.__serialized[item] = 1 # type: ignore[index]
  293. else:
  294. if first(
  295. store.triples_choices(
  296. # type error: Argument 1 to "triples_choices" of "Graph" has incompatible type "Tuple[Identifier, URIRef, List[URIRef]]"; expected "Union[Tuple[List[Node], Node, Node], Tuple[Node, List[Node], Node], Tuple[Node, Node, List[Node]]]"
  297. (object, RDF.type, [OWL_NS.Class, RDFS.Class]) # type: ignore[arg-type]
  298. )
  299. ) and isinstance(object, URIRef):
  300. writer.attribute(RDFVOC.resource, self.relativize(object))
  301. elif depth <= self.max_depth:
  302. self.subject(object, depth + 1)
  303. elif isinstance(object, BNode):
  304. if (
  305. object not in self.__serialized
  306. and (object, None, None) in store
  307. and len(list(store.subjects(object=object))) == 1
  308. ):
  309. # inline blank nodes if they haven't been serialized yet
  310. # and are only referenced once (regardless of depth)
  311. self.subject(object, depth + 1)
  312. else:
  313. writer.attribute(RDFVOC.nodeID, fix(object))
  314. else:
  315. writer.attribute(RDFVOC.resource, self.relativize(object))
  316. writer.pop(predicate)