#!/usr/bin/env python3
from __future__ import annotations
__doc__ = """\
N-Triples Parser
License: GPL 2, W3C, BSD, or MIT
Author: Sean B. Palmer, inamidst.com
"""
import codecs
import re
from io import BytesIO, StringIO, TextIOBase
from typing import (
IO,
TYPE_CHECKING,
Any,
Match,
MutableMapping,
Optional,
Pattern,
TextIO,
Union,
)
from rdflib.compat import _string_escape_map, decodeUnicodeEscape
from rdflib.exceptions import ParserError as ParseError
from rdflib.parser import InputSource, Parser
from rdflib.term import BNode as bNode
from rdflib.term import Literal
from rdflib.term import URIRef
from rdflib.term import URIRef as URI
if TYPE_CHECKING:
import typing_extensions as te
from rdflib.graph import Graph, _ObjectType, _PredicateType, _SubjectType
__all__ = [
"unquote",
"uriquote",
"W3CNTriplesParser",
"NTGraphSink",
"NTParser",
"DummySink",
]
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
[docs]class DummySink:
[docs] def __init__(self):
self.length = 0
[docs] def triple(self, s, p, o):
self.length += 1
print(s, p, o)
r_safe = re.compile(r"([\x20\x21\x23-\x5B\x5D-\x7E]+)")
r_quot = re.compile(r"""\\([tbnrf"'\\])""")
r_uniquot = re.compile(r"\\u([0-9A-Fa-f]{4})|\\U([0-9A-Fa-f]{8})")
[docs]def unquote(s: str) -> str:
"""Unquote an N-Triples string."""
if not validate:
if isinstance(s, str): # nquads
s = decodeUnicodeEscape(s)
else:
s = s.decode("unicode-escape") # type: ignore[unreachable]
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(_string_escape_map[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: str) -> str:
if not validate:
return uri
else:
return r_hibyte.sub(lambda m: "%%%02X" % ord(m.group(1)), uri)
_BNodeContextType = MutableMapping[str, bNode]
[docs]class W3CNTriplesParser:
"""An N-Triples Parser.
This is a legacy-style Triples parser for NTriples provided by W3C
Usage::
p = W3CNTriplesParser(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
`W3CNTriplesParser`.
"""
__slots__ = ("_bnode_ids", "sink", "buffer", "file", "line")
[docs] def __init__(
self,
sink: Optional[Union[DummySink, "NTGraphSink"]] = None,
bnode_context: Optional[_BNodeContextType] = None,
):
if bnode_context is not None:
self._bnode_ids = bnode_context
else:
self._bnode_ids = {}
self.sink: Union[DummySink, "NTGraphSink"]
if sink is not None:
self.sink = sink
else:
self.sink = DummySink()
self.buffer: Optional[str] = None
self.file: Optional[Union[TextIO, codecs.StreamReader]] = None
self.line: Optional[str] = ""
[docs] def parse(
self,
f: Union[TextIO, IO[bytes], codecs.StreamReader],
bnode_context: Optional[_BNodeContextType] = None,
) -> Union[DummySink, "NTGraphSink"]:
"""
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 # type: ignore[assignment]
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: Union[bytes, bytearray, str], **kwargs) -> None:
"""Parse s as an N-Triples string."""
if not isinstance(s, (str, bytes, bytearray)):
raise ParseError("Item to parse must be a string instance.")
f: Union[codecs.StreamReader, StringIO]
if isinstance(s, (bytes, bytearray)):
f = codecs.getreader("utf-8")(BytesIO(s))
else:
f = StringIO(s)
self.parse(f, **kwargs)
[docs] def readline(self) -> Optional[str]:
"""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:
# type error: Item "None" of "Union[TextIO, StreamReader, None]" has no attribute "read"
buffer = self.file.read(bufsiz) # type: ignore[union-attr]
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:
# type error: Item "None" of "Union[TextIO, StreamReader, None]" has no attribute "read"
buffer = self.file.read(bufsiz) # type: ignore[union-attr]
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: Optional[_BNodeContextType] = None) -> 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: str) -> bool:
return self.line.startswith(token) # type: ignore[union-attr]
[docs] def eat(self, pattern: Pattern[str]) -> Match[str]:
m = pattern.match(self.line) # type: ignore[arg-type]
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() :] # type: ignore[index]
return m
[docs] def subject(self, bnode_context=None) -> Union[bNode, URIRef]:
# @@ 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) -> URIRef:
pred = self.uriref()
if not pred:
raise ParseError("Predicate must be uriref")
return pred
[docs] def object(
self, bnode_context: Optional[_BNodeContextType] = None
) -> Union[URI, bNode, Literal]:
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) -> Union["te.Literal[False]", URI]:
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: Optional[_BNodeContextType] = None
) -> Union["te.Literal[False]", bNode]:
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 specific 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) -> Union["te.Literal[False]", Literal]:
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:
__slots__ = ("g",)
[docs] def __init__(self, graph: "Graph"):
self.g = graph
[docs] def triple(self, s: "_SubjectType", p: "_PredicateType", o: "_ObjectType") -> None:
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: InputSource, sink: "Graph", **kwargs: Any) -> None:
"""
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 `.W3CNTriplesParser.parse`
"""
f: Union[TextIO, IO[bytes], codecs.StreamReader]
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 # type: ignore[assignment]
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()
