Source code for rdflib.parser

Parser plugin interface.

This module defines the parser plugin interface and contains other
related parser support code.

The module is mainly useful for those wanting to write a parser that
can plugin to rdflib. If you are wanting to invoke a parser you likely
want to do so through the Graph class parse method.


import codecs
import os
import pathlib
import sys
from io import BufferedIOBase, BytesIO, RawIOBase, StringIO, TextIOBase, TextIOWrapper
from typing import (
from urllib.error import HTTPError
from urllib.parse import urljoin
from urllib.request import Request, url2pathname, urlopen
from xml.sax import xmlreader

import rdflib.util
from rdflib import __version__
from rdflib.namespace import Namespace
from rdflib.term import URIRef

    from http.client import HTTPMessage, HTTPResponse

    from rdflib import Graph

__all__ = [

[docs]class Parser(object): __slots__ = ()
[docs] def __init__(self): pass
[docs] def parse(self, source: "InputSource", sink: "Graph"): pass
class BytesIOWrapper(BufferedIOBase): __slots__ = ("wrapped", "encoded", "encoding") def __init__(self, wrapped: str, encoding="utf-8"): super(BytesIOWrapper, self).__init__() self.wrapped = wrapped self.encoding = encoding self.encoded = None def read(self, *args, **kwargs): if self.encoded is None: b, blen = codecs.getencoder(self.encoding)(self.wrapped) self.encoded = BytesIO(b) return*args, **kwargs) def read1(self, *args, **kwargs): if self.encoded is None: b = codecs.getencoder(self.encoding)(self.wrapped) self.encoded = BytesIO(b) return self.encoded.read1(*args, **kwargs) def readinto(self, *args, **kwargs): raise NotImplementedError() def readinto1(self, *args, **kwargs): raise NotImplementedError() def write(self, *args, **kwargs): raise NotImplementedError()
[docs]class InputSource(xmlreader.InputSource, object): """ TODO: """
[docs] def __init__(self, system_id: Optional[str] = None): xmlreader.InputSource.__init__(self, system_id=system_id) self.content_type: Optional[str] = None self.auto_close = False # see Graph.parse(), true if opened by us
[docs] def close(self): c = self.getCharacterStream() if c and hasattr(c, "close"): try: c.close() except Exception: pass f = self.getByteStream() if f and hasattr(f, "close"): try: f.close() except Exception: pass
[docs]class PythonInputSource(InputSource): """ Constructs an RDFLib Parser InputSource from a Python data structure, for example, loaded from JSON with json.load or json.loads: >>> import json >>> as_string = \"\"\"{ ... "@context" : {"ex" : ""}, ... "@graph": [{"@type": "ex:item", "@id": "#example"}] ... }\"\"\" >>> as_python = json.loads(as_string) >>> source = create_input_source(data=as_python) >>> isinstance(source, PythonInputSource) True """
[docs] def __init__(self, data, system_id=None): self.content_type = None self.auto_close = False # see Graph.parse(), true if opened by us self.public_id = None self.system_id = system_id = data
[docs] def getPublicId(self): # noqa: N802 return self.public_id
[docs] def setPublicId(self, public_id): # noqa: N802 self.public_id = public_id
[docs] def getSystemId(self): # noqa: N802 return self.system_id
[docs] def setSystemId(self, system_id): # noqa: N802 self.system_id = system_id
[docs] def close(self): = None
[docs]class StringInputSource(InputSource): """ Constructs an RDFLib Parser InputSource from a Python String or Bytes """
[docs] def __init__( self, value: Union[str, bytes], encoding: str = "utf-8", system_id: Optional[str] = None, ): super(StringInputSource, self).__init__(system_id) stream: Union[BinaryIO, TextIO] if isinstance(value, str): stream = StringIO(value) self.setCharacterStream(stream) self.setEncoding(encoding) b_stream = BytesIOWrapper(value, encoding) self.setByteStream(b_stream) else: stream = BytesIO(value) self.setByteStream(stream) c_stream = TextIOWrapper(stream, encoding) self.setCharacterStream(c_stream) self.setEncoding(c_stream.encoding)
headers = { "User-agent": "rdflib-%s (;" % __version__ }
[docs]class URLInputSource(InputSource): """ Constructs an RDFLib Parser InputSource from a URL to read it from the Web. """ links: List[str]
[docs] @classmethod def getallmatchingheaders(cls, message: "HTTPMessage", name): # This is reimplemented here, because the method # getallmatchingheaders from HTTPMessage is broken since Python 3.0 name = name.lower() return [val for key, val in message.items() if key.lower() == name]
[docs] def get_alternates(self, type_: Optional[str] = None) -> List[str]: typestr: Optional[str] = f'type="{type_}"' if type_ else None relstr = 'rel="alternate"' alts = [] for link in self.links: parts = [p.strip() for p in link.split(";")] if relstr not in parts: continue if typestr: if typestr in parts: alts.append(parts[0].strip("<>")) else: alts.append(parts[0].strip("<>")) return alts
[docs] def __init__(self, system_id: Optional[str] = None, format: Optional[str] = None): super(URLInputSource, self).__init__(system_id) self.url = system_id # copy headers to change myheaders = dict(headers) if format == "xml": myheaders["Accept"] = "application/rdf+xml, */*;q=0.1" elif format == "n3": myheaders["Accept"] = "text/n3, */*;q=0.1" elif format in ["turtle", "ttl"]: myheaders["Accept"] = "text/turtle, application/x-turtle, */*;q=0.1" elif format == "nt": myheaders["Accept"] = "text/plain, */*;q=0.1" elif format == "trig": myheaders["Accept"] = "application/trig, */*;q=0.1" elif format == "trix": myheaders["Accept"] = "application/trix, */*;q=0.1" elif format == "json-ld": myheaders[ "Accept" ] = "application/ld+json, application/json;q=0.9, */*;q=0.1" else: # if format not given, create an Accept header from all registered # parser Media Types from rdflib.parser import Parser from rdflib.plugin import plugins acc = [] for p in plugins(kind=Parser): # only get parsers if "/" in # all Media Types known have a / in them acc.append( myheaders["Accept"] = ", ".join(acc) req = Request(system_id, None, myheaders) # type: ignore[arg-type] def _urlopen(req: Request) -> Any: try: return urlopen(req) except HTTPError as ex: # 308 (Permanent Redirect) is not supported by current python version(s) # See # This custom error handling should be removed once all # supported versions of python support 308. if ex.code == 308: req.full_url = ex.headers.get("Location") return _urlopen(req) else: raise response: HTTPResponse = _urlopen(req) self.url = response.geturl() # in case redirections took place self.links = self.get_links(response) if format in ("json-ld", "application/ld+json"): alts = self.get_alternates(type_="application/ld+json") for link in alts: full_link = urljoin(self.url, link) if full_link != self.url and full_link != system_id: response = _urlopen(Request(full_link)) self.url = response.geturl() # in case redirections took place break self.setPublicId(self.url) content_types = self.getallmatchingheaders(response.headers, "content-type") self.content_type = content_types[0] if content_types else None if self.content_type is not None: self.content_type = self.content_type.split(";", 1)[0] self.setByteStream(response) # TODO: self.setEncoding(encoding) self.response_info = # a mimetools.Message instance
[docs] def __repr__(self): return self.url
[docs]class FileInputSource(InputSource):
[docs] def __init__( self, file: Union[BinaryIO, TextIO, TextIOBase, RawIOBase, BufferedIOBase] ): base = pathlib.Path.cwd().as_uri() system_id = URIRef(pathlib.Path(, base=base) # type: ignore[union-attr] super(FileInputSource, self).__init__(system_id) self.file = file if isinstance(file, TextIOBase): # Python3 unicode fp self.setCharacterStream(file) self.setEncoding(file.encoding) try: b = file.buffer # type: ignore[attr-defined] self.setByteStream(b) except (AttributeError, LookupError): self.setByteStream(file) else: self.setByteStream(file)
# We cannot set characterStream here because # we do not know the Raw Bytes File encoding.
[docs] def __repr__(self): return repr(self.file)
def create_input_source( source: Optional[ Union[IO[bytes], TextIO, InputSource, str, bytes, pathlib.PurePath] ] = None, publicID: Optional[str] = None, # noqa: N803 location: Optional[str] = None, file: Optional[Union[BinaryIO, TextIO]] = None, data: Union[str, bytes, dict] = None, format: str = None, ) -> InputSource: """ Return an appropriate InputSource instance for the given parameters. """ # test that exactly one of source, location, file, and data is not None. non_empty_arguments = list( filter( lambda v: v is not None, [source, location, file, data], ) ) if len(non_empty_arguments) != 1: raise ValueError( "exactly one of source, location, file or data must be given", ) input_source = None if source is not None: if isinstance(source, InputSource): input_source = source else: if isinstance(source, str): location = source elif isinstance(source, pathlib.PurePath): location = str(source) elif isinstance(source, bytes): data = source elif hasattr(source, "read") and not isinstance(source, Namespace): # type: ignore[unreachable] f = source input_source = InputSource() if hasattr(source, "encoding"): input_source.setCharacterStream(source) input_source.setEncoding(source.encoding) # type: ignore[union-attr] try: b = file.buffer # type: ignore[union-attr] input_source.setByteStream(b) except (AttributeError, LookupError): input_source.setByteStream(source) else: input_source.setByteStream(f) if f is sys.stdin: input_source.setSystemId("file:///dev/stdin") elif hasattr(f, "name"): input_source.setSystemId( else: raise Exception( "Unexpected type '%s' for source '%s'" % (type(source), source) ) absolute_location = None # Further to fix for issue 130 auto_close = False # make sure we close all file handles we open if location is not None: ( absolute_location, auto_close, file, input_source, ) = _create_input_source_from_location( file=file, format=format, input_source=input_source, location=location, ) if file is not None: input_source = FileInputSource(file) if data is not None: if isinstance(data, dict): input_source = PythonInputSource(data) auto_close = True elif isinstance(data, (str, bytes, bytearray)): input_source = StringInputSource(data) auto_close = True else: raise RuntimeError(f"parse data can only str, or bytes. not: {type(data)}") if input_source is None: raise Exception("could not create InputSource") else: input_source.auto_close |= auto_close if publicID is not None: # Further to fix for issue 130 input_source.setPublicId(publicID) # Further to fix for issue 130 elif input_source.getPublicId() is None: input_source.setPublicId(absolute_location or "") return input_source def _create_input_source_from_location( file: Optional[Union[BinaryIO, TextIO]], format: Optional[str], input_source: Optional[InputSource], location: str, ) -> Tuple[URIRef, bool, Optional[Union[BinaryIO, TextIO]], Optional[InputSource]]: # Fix for Windows problem and # # NOTE: using pathlib.Path.exists on a URL fails on windows as it is not a # valid path. However os.path.exists() returns false for a URL on windows # which is why it is being used instead. if os.path.exists(location): location = pathlib.Path(location).absolute().as_uri() base = pathlib.Path.cwd().as_uri() absolute_location = URIRef(rdflib.util._iri2uri(location), base=base) if absolute_location.startswith("file:///"): filename = url2pathname(absolute_location.replace("file:///", "/")) file = open(filename, "rb") else: input_source = URLInputSource(absolute_location, format) auto_close = True # publicID = publicID or absolute_location # Further to fix # for issue 130 return absolute_location, auto_close, file, input_source