Source code for rdflib.plugins.parsers.ntriples

#!/usr/bin/env python3

__doc__ = """\
N-Triples Parser
License: GPL 2, W3C, BSD, or MIT
Author: Sean B. Palmer, inamidst.com
"""

import re
import codecs

from rdflib.term import URIRef as URI
from rdflib.term import BNode as bNode
from rdflib.term import Literal
from rdflib.compat import decodeUnicodeEscape
from rdflib.exceptions import ParserError as ParseError
from rdflib.parser import Parser

from io import StringIO, TextIOBase, BytesIO

__all__ = ["unquote", "uriquote", "W3CNTriplesParser", "NTGraphSink", "NTParser"]

uriref = r'<([^:]+:[^\s"<>]*)>'
literal = r'"([^"\\]*(?:\\.[^"\\]*)*)"'
litinfo = r"(?:@([a-zA-Z]+(?:-[a-zA-Z0-9]+)*)|\^\^" + uriref + r")?"

r_line = re.compile(r"([^\r\n]*)(?:\r\n|\r|\n)")
r_wspace = re.compile(r"[ \t]*")
r_wspaces = re.compile(r"[ \t]+")
r_tail = re.compile(r"[ \t]*\.[ \t]*(#.*)?")
r_uriref = re.compile(uriref)
r_nodeid = re.compile(r"_:([A-Za-z0-9_:]([-A-Za-z0-9_:\.]*[-A-Za-z0-9_:])?)")
r_literal = re.compile(literal + litinfo)

bufsiz = 2048
validate = False


class DummySink(object):
    def __init__(self):
        self.length = 0

    def triple(self, s, p, o):
        self.length += 1
        print(s, p, o)


quot = {"t": "\t", "n": "\n", "r": "\r", '"': '"', "\\": "\\"}
r_safe = re.compile(r"([\x20\x21\x23-\x5B\x5D-\x7E]+)")
r_quot = re.compile(r'\\(t|n|r|"|\\)')
r_uniquot = re.compile(r"\\u([0-9A-F]{4})|\\U([0-9A-F]{8})")


[docs]def unquote(s): """Unquote an N-Triples string.""" if not validate: if isinstance(s, str): # nquads s = decodeUnicodeEscape(s) else: s = s.decode("unicode-escape") return s else: result = [] while s: m = r_safe.match(s) if m: s = s[m.end() :] result.append(m.group(1)) continue m = r_quot.match(s) if m: s = s[2:] result.append(quot[m.group(1)]) continue m = r_uniquot.match(s) if m: s = s[m.end() :] u, U = m.groups() codepoint = int(u or U, 16) if codepoint > 0x10FFFF: raise ParseError("Disallowed codepoint: %08X" % codepoint) result.append(chr(codepoint)) elif s.startswith("\\"): raise ParseError("Illegal escape at: %s..." % s[:10]) else: raise ParseError("Illegal literal character: %r" % s[0]) return "".join(result)
r_hibyte = re.compile(r"([\x80-\xFF])")
[docs]def uriquote(uri): if not validate: return uri else: return r_hibyte.sub(lambda m: "%%%02X" % ord(m.group(1)), uri)
[docs]class W3CNTriplesParser(object): """An N-Triples Parser. This is a legacy-style Triples parser for NTriples provided by W3C Usage:: p = NTriplesParser(sink=MySink()) sink = p.parse(f) # file; use parsestring for a string To define a context in which blank node identifiers refer to the same blank node across instances of NTriplesParser, pass the same dict as `bnode_context` to each instance. By default, a new blank node context is created for each instance of `NTriplesParser`. """ __slots__ = ("_bnode_ids", "sink", "buffer", "file", "line")
[docs] def __init__(self, sink=None, bnode_context=None): if bnode_context is not None: self._bnode_ids = bnode_context else: self._bnode_ids = {} if sink is not None: self.sink = sink else: self.sink = DummySink() self.buffer = None self.file = None self.line = ""
[docs] def parse(self, f, bnode_context=None): """ Parse f as an N-Triples file. :type f: :term:`file object` :param f: the N-Triples source :type bnode_context: `dict`, optional :param bnode_context: a dict mapping blank node identifiers (e.g., ``a`` in ``_:a``) to `~rdflib.term.BNode` instances. An empty dict can be passed in to define a distinct context for a given call to `parse`. """ if not hasattr(f, "read"): raise ParseError("Item to parse must be a file-like object.") if not hasattr(f, "encoding") and not hasattr(f, "charbuffer"): # someone still using a bytestream here? f = codecs.getreader("utf-8")(f) self.file = f self.buffer = "" while True: self.line = self.readline() if self.line is None: break try: self.parseline(bnode_context=bnode_context) except ParseError: raise ParseError("Invalid line: {}".format(self.line)) return self.sink
[docs] def parsestring(self, s, **kwargs): """Parse s as an N-Triples string.""" if not isinstance(s, (str, bytes, bytearray)): raise ParseError("Item to parse must be a string instance.") if isinstance(s, (bytes, bytearray)): f = codecs.getreader("utf-8")(BytesIO(s)) else: f = StringIO(s) self.parse(f, **kwargs)
[docs] def readline(self): """Read an N-Triples line from buffered input.""" # N-Triples lines end in either CRLF, CR, or LF # Therefore, we can't just use f.readline() if not self.buffer: buffer = self.file.read(bufsiz) if not buffer: return None self.buffer = buffer while True: m = r_line.match(self.buffer) if m: # the more likely prospect self.buffer = self.buffer[m.end() :] return m.group(1) else: buffer = self.file.read(bufsiz) if not buffer and not self.buffer.isspace(): # Last line does not need to be terminated with a newline buffer += "\n" elif not buffer: return None self.buffer += buffer
[docs] def parseline(self, bnode_context=None): self.eat(r_wspace) if (not self.line) or self.line.startswith("#"): return # The line is empty or a comment subject = self.subject(bnode_context) self.eat(r_wspaces) predicate = self.predicate() self.eat(r_wspaces) object_ = self.object(bnode_context) self.eat(r_tail) if self.line: raise ParseError("Trailing garbage: {}".format(self.line)) self.sink.triple(subject, predicate, object_)
[docs] def peek(self, token): return self.line.startswith(token)
[docs] def eat(self, pattern): m = pattern.match(self.line) if not m: # @@ Why can't we get the original pattern? # print(dir(pattern)) # print repr(self.line), type(self.line) raise ParseError("Failed to eat %s at %s" % (pattern.pattern, self.line)) self.line = self.line[m.end() :] return m
[docs] def subject(self, bnode_context=None): # @@ Consider using dictionary cases subj = self.uriref() or self.nodeid(bnode_context) if not subj: raise ParseError("Subject must be uriref or nodeID") return subj
[docs] def predicate(self): pred = self.uriref() if not pred: raise ParseError("Predicate must be uriref") return pred
[docs] def object(self, bnode_context=None): objt = self.uriref() or self.nodeid(bnode_context) or self.literal() if objt is False: raise ParseError("Unrecognised object type") return objt
[docs] def uriref(self): if self.peek("<"): uri = self.eat(r_uriref).group(1) uri = unquote(uri) uri = uriquote(uri) return URI(uri) return False
[docs] def nodeid(self, bnode_context=None): if self.peek("_"): # Fix for https://github.com/RDFLib/rdflib/issues/204 if bnode_context is None: bnode_context = self._bnode_ids bnode_id = self.eat(r_nodeid).group(1) new_id = bnode_context.get(bnode_id, None) if new_id is not None: # Re-map to id specfic to this doc return bNode(new_id) else: # Replace with freshly-generated document-specific BNode id bnode = bNode() # Store the mapping bnode_context[bnode_id] = bnode return bnode return False
[docs] def literal(self): if self.peek('"'): lit, lang, dtype = self.eat(r_literal).groups() if lang: lang = lang else: lang = None if dtype: dtype = unquote(dtype) dtype = uriquote(dtype) dtype = URI(dtype) else: dtype = None if lang and dtype: raise ParseError("Can't have both a language and a datatype") lit = unquote(lit) return Literal(lit, lang, dtype) return False
[docs]class NTGraphSink(object): __slots__ = ("g",)
[docs] def __init__(self, graph): self.g = graph
[docs] def triple(self, s, p, o): self.g.add((s, p, o))
[docs]class NTParser(Parser): """parser for the ntriples format, often stored with the .nt extension See http://www.w3.org/TR/rdf-testcases/#ntriples""" __slots__ = ()
[docs] @classmethod def parse(cls, source, sink, **kwargs): """ Parse the NT format :type source: `rdflib.parser.InputSource` :param source: the source of NT-formatted data :type sink: `rdflib.graph.Graph` :param sink: where to send parsed triples :param kwargs: Additional arguments to pass to `.NTriplesParser.parse` """ f = source.getCharacterStream() if not f: b = source.getByteStream() # TextIOBase includes: StringIO and TextIOWrapper if isinstance(b, TextIOBase): # f is not really a ByteStream, but a CharacterStream f = b else: # since N-Triples 1.1 files can and should be utf-8 encoded f = codecs.getreader("utf-8")(b) parser = W3CNTriplesParser(NTGraphSink(sink)) parser.parse(f, **kwargs) f.close()