130 lines
3.9 KiB
Python
130 lines
3.9 KiB
Python
# defusedxml
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#
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# Copyright (c) 2013 by Christian Heimes <christian@python.org>
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# Licensed to PSF under a Contributor Agreement.
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# See https://www.python.org/psf/license for licensing details.
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"""Common constants, exceptions and helpe functions
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"""
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import sys
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import xml.parsers.expat
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PY3 = sys.version_info[0] == 3
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# Fail early when pyexpat is not installed correctly
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if not hasattr(xml.parsers.expat, "ParserCreate"):
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raise ImportError("pyexpat") # pragma: no cover
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class DefusedXmlException(ValueError):
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"""Base exception"""
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def __repr__(self):
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return str(self)
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class DTDForbidden(DefusedXmlException):
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"""Document type definition is forbidden"""
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def __init__(self, name, sysid, pubid):
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super(DTDForbidden, self).__init__()
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self.name = name
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self.sysid = sysid
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self.pubid = pubid
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def __str__(self):
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tpl = "DTDForbidden(name='{}', system_id={!r}, public_id={!r})"
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return tpl.format(self.name, self.sysid, self.pubid)
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class EntitiesForbidden(DefusedXmlException):
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"""Entity definition is forbidden"""
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def __init__(self, name, value, base, sysid, pubid, notation_name):
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super(EntitiesForbidden, self).__init__()
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self.name = name
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self.value = value
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self.base = base
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self.sysid = sysid
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self.pubid = pubid
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self.notation_name = notation_name
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def __str__(self):
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tpl = "EntitiesForbidden(name='{}', system_id={!r}, public_id={!r})"
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return tpl.format(self.name, self.sysid, self.pubid)
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class ExternalReferenceForbidden(DefusedXmlException):
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"""Resolving an external reference is forbidden"""
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def __init__(self, context, base, sysid, pubid):
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super(ExternalReferenceForbidden, self).__init__()
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self.context = context
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self.base = base
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self.sysid = sysid
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self.pubid = pubid
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def __str__(self):
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tpl = "ExternalReferenceForbidden(system_id='{}', public_id={})"
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return tpl.format(self.sysid, self.pubid)
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class NotSupportedError(DefusedXmlException):
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"""The operation is not supported"""
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def _apply_defusing(defused_mod):
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assert defused_mod is sys.modules[defused_mod.__name__]
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stdlib_name = defused_mod.__origin__
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__import__(stdlib_name, {}, {}, ["*"])
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stdlib_mod = sys.modules[stdlib_name]
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stdlib_names = set(dir(stdlib_mod))
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for name, obj in vars(defused_mod).items():
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if name.startswith("_") or name not in stdlib_names:
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continue
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setattr(stdlib_mod, name, obj)
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return stdlib_mod
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def _generate_etree_functions(DefusedXMLParser, _TreeBuilder, _parse, _iterparse):
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"""Factory for functions needed by etree, dependent on whether
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cElementTree or ElementTree is used."""
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def parse(source, parser=None, forbid_dtd=False, forbid_entities=True, forbid_external=True):
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if parser is None:
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parser = DefusedXMLParser(
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target=_TreeBuilder(),
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forbid_dtd=forbid_dtd,
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forbid_entities=forbid_entities,
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forbid_external=forbid_external,
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)
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return _parse(source, parser)
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def iterparse(
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source,
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events=None,
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parser=None,
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forbid_dtd=False,
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forbid_entities=True,
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forbid_external=True,
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):
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if parser is None:
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parser = DefusedXMLParser(
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target=_TreeBuilder(),
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forbid_dtd=forbid_dtd,
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forbid_entities=forbid_entities,
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forbid_external=forbid_external,
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)
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return _iterparse(source, events, parser)
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def fromstring(text, forbid_dtd=False, forbid_entities=True, forbid_external=True):
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parser = DefusedXMLParser(
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target=_TreeBuilder(),
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forbid_dtd=forbid_dtd,
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forbid_entities=forbid_entities,
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forbid_external=forbid_external,
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)
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parser.feed(text)
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return parser.close()
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return parse, iterparse, fromstring
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