basic subscriptions system

1 files changed, 59 insertions, 0 deletions

diff --git a/python/defusedxml/expatreader.py b/python/defusedxml/expatreader.py
new file mode 100644
index 0000000..ef6bc39
--- /dev/null
+++ b/python/defusedxml/expatreader.py
@@ -0,0 +1,59 @@
+# defusedxml
+#
+# Copyright (c) 2013 by Christian Heimes <christian@python.org>
+# Licensed to PSF under a Contributor Agreement.
+# See http://www.python.org/psf/license for licensing details.
+"""Defused xml.sax.expatreader
+"""
+from __future__ import print_function, absolute_import
+
+from xml.sax.expatreader import ExpatParser as _ExpatParser
+
+from .common import (DTDForbidden, EntitiesForbidden,
+                     ExternalReferenceForbidden)
+
+__origin__ = "xml.sax.expatreader"
+
+
+class DefusedExpatParser(_ExpatParser):
+    """Defused SAX driver for the pyexpat C module."""
+
+    def __init__(self, namespaceHandling=0, bufsize=2 ** 16 - 20,
+                 forbid_dtd=False, forbid_entities=True,
+                 forbid_external=True):
+        _ExpatParser.__init__(self, namespaceHandling, bufsize)
+        self.forbid_dtd = forbid_dtd
+        self.forbid_entities = forbid_entities
+        self.forbid_external = forbid_external
+
+    def defused_start_doctype_decl(self, name, sysid, pubid,
+                                   has_internal_subset):
+        raise DTDForbidden(name, sysid, pubid)
+
+    def defused_entity_decl(self, name, is_parameter_entity, value, base,
+                            sysid, pubid, notation_name):
+        raise EntitiesForbidden(name, value, base, sysid, pubid, notation_name)
+
+    def defused_unparsed_entity_decl(self, name, base, sysid, pubid,
+                                     notation_name):
+        # expat 1.2
+        raise EntitiesForbidden(name, None, base, sysid, pubid, notation_name)
+
+    def defused_external_entity_ref_handler(self, context, base, sysid,
+                                            pubid):
+        raise ExternalReferenceForbidden(context, base, sysid, pubid)
+
+    def reset(self):
+        _ExpatParser.reset(self)
+        parser = self._parser
+        if self.forbid_dtd:
+            parser.StartDoctypeDeclHandler = self.defused_start_doctype_decl
+        if self.forbid_entities:
+            parser.EntityDeclHandler = self.defused_entity_decl
+            parser.UnparsedEntityDeclHandler = self.defused_unparsed_entity_decl
+        if self.forbid_external:
+            parser.ExternalEntityRefHandler = self.defused_external_entity_ref_handler
+
+
+def create_parser(*args, **kwargs):
+    return DefusedExpatParser(*args, **kwargs)