Source code for rdflib.plugins.parsers.trix

"""
A TriX parser for RDFLib
"""
from rdflib.namespace import Namespace
from rdflib.term import URIRef
from rdflib.term import BNode
from rdflib.term import Literal
from rdflib.graph import Graph
from rdflib.exceptions import ParserError
from rdflib.parser import Parser


from xml.sax.saxutils import handler
from xml.sax import make_parser
from xml.sax.handler import ErrorHandler

__all__ = ["create_parser", "TriXHandler", "TriXParser"]


TRIXNS = Namespace("http://www.w3.org/2004/03/trix/trix-1/")
XMLNS = Namespace("http://www.w3.org/XML/1998/namespace")


[docs]class TriXHandler(handler.ContentHandler): """An Sax Handler for TriX. See http://sw.nokia.com/trix/"""
[docs] def __init__(self, store): self.store = store self.preserve_bnode_ids = False self.reset()
[docs] def reset(self): self.bnode = {} self.graph = None self.triple = None self.state = 0 self.lang = None self.datatype = None
# ContentHandler methods
[docs] def setDocumentLocator(self, locator): self.locator = locator
[docs] def startDocument(self): pass
[docs] def startPrefixMapping(self, prefix, namespace): pass
[docs] def endPrefixMapping(self, prefix): pass
[docs] def startElementNS(self, name, qname, attrs): if name[0] != str(TRIXNS): self.error( "Only elements in the TriX namespace are allowed. %s!=%s" % (name[0], TRIXNS) ) if name[1] == "TriX": if self.state == 0: self.state = 1 else: self.error("Unexpected TriX element") elif name[1] == "graph": if self.state == 1: self.state = 2 else: self.error("Unexpected graph element") elif name[1] == "uri": if self.state == 2: # the context uri self.state = 3 elif self.state == 4: # part of a triple pass else: self.error("Unexpected uri element") elif name[1] == "triple": if self.state == 2: if self.graph is None: # anonymous graph, create one with random bnode id self.graph = Graph(store=self.store) # start of a triple self.triple = [] self.state = 4 else: self.error("Unexpected triple element") elif name[1] == "typedLiteral": if self.state == 4: # part of triple self.lang = None self.datatype = None try: self.lang = attrs.getValue((str(XMLNS), "lang")) except: # language not required - ignore pass try: self.datatype = attrs.getValueByQName("datatype") except KeyError: self.error("No required attribute 'datatype'") else: self.error("Unexpected typedLiteral element") elif name[1] == "plainLiteral": if self.state == 4: # part of triple self.lang = None self.datatype = None try: self.lang = attrs.getValue((str(XMLNS), "lang")) except: # language not required - ignore pass else: self.error("Unexpected plainLiteral element") elif name[1] == "id": if self.state == 2: # the context uri self.state = 3 elif self.state == 4: # part of triple pass else: self.error("Unexpected id element") else: self.error("Unknown element %s in TriX namespace" % name[1]) self.chars = ""
[docs] def endElementNS(self, name, qname): if name[0] != str(TRIXNS): self.error( "Only elements in the TriX namespace are allowed. %s!=%s" % (name[0], TRIXNS) ) if name[1] == "uri": if self.state == 3: self.graph = Graph( store=self.store, identifier=URIRef(self.chars.strip()) ) self.state = 2 elif self.state == 4: self.triple += [URIRef(self.chars.strip())] else: self.error( "Illegal internal self.state - This should never " + "happen if the SAX parser ensures XML syntax correctness" ) elif name[1] == "id": if self.state == 3: self.graph = Graph( self.store, identifier=self.get_bnode(self.chars.strip()) ) self.state = 2 elif self.state == 4: self.triple += [self.get_bnode(self.chars.strip())] else: self.error( "Illegal internal self.state - This should never " + "happen if the SAX parser ensures XML syntax correctness" ) elif name[1] == "plainLiteral" or name[1] == "typedLiteral": if self.state == 4: self.triple += [ Literal(self.chars, lang=self.lang, datatype=self.datatype) ] else: self.error( "This should never happen if the SAX parser " + "ensures XML syntax correctness" ) elif name[1] == "triple": if self.state == 4: if len(self.triple) != 3: self.error( "Triple has wrong length, got %d elements: %s" % (len(self.triple), self.triple) ) self.graph.add(self.triple) # self.store.store.add(self.triple,context=self.graph) # self.store.addN([self.triple+[self.graph]]) self.state = 2 else: self.error( "This should never happen if the SAX parser " + "ensures XML syntax correctness" ) elif name[1] == "graph": self.graph = None self.state = 1 elif name[1] == "TriX": self.state = 0 else: self.error("Unexpected close element")
[docs] def get_bnode(self, label): if self.preserve_bnode_ids: bn = BNode(label) else: if label in self.bnode: bn = self.bnode[label] else: bn = BNode(label) self.bnode[label] = bn return bn
[docs] def characters(self, content): self.chars += content
[docs] def ignorableWhitespace(self, content): pass
[docs] def processingInstruction(self, target, data): pass
[docs] def error(self, message): locator = self.locator info = "%s:%s:%s: " % ( locator.getSystemId(), locator.getLineNumber(), locator.getColumnNumber(), ) raise ParserError(info + message)
[docs]def create_parser(store): parser = make_parser() try: # Workaround for bug in expatreader.py. Needed when # expatreader is trying to guess a prefix. parser.start_namespace_decl("xml", "http://www.w3.org/XML/1998/namespace") except AttributeError: pass # Not present in Jython (at least) parser.setFeature(handler.feature_namespaces, 1) trix = TriXHandler(store) parser.setContentHandler(trix) parser.setErrorHandler(ErrorHandler()) return parser
[docs]class TriXParser(Parser): """A parser for TriX. See http://sw.nokia.com/trix/"""
[docs] def __init__(self): pass
[docs] def parse(self, source, sink, **args): assert ( sink.store.context_aware ), "TriXParser must be given a context aware store." self._parser = create_parser(sink.store) content_handler = self._parser.getContentHandler() preserve_bnode_ids = args.get("preserve_bnode_ids", None) if preserve_bnode_ids is not None: content_handler.preserve_bnode_ids = preserve_bnode_ids # We're only using it once now # content_handler.reset() # self._parser.reset() self._parser.parse(source)