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# Copyright (C) 2007-2010 by the Free Software Foundation, Inc.
#
# This file is part of GNU Mailman.
#
# GNU Mailman is free software: you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option)
# any later version.
#
# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along with
# GNU Mailman. If not, see <http://www.gnu.org/licenses/>.
"""The implicit destination rule."""
from __future__ import absolute_import, unicode_literals
__metaclass__ = type
__all__ = [
'ImplicitDestination',
]
import re
from email.utils import getaddresses
from zope.interface import implements
from mailman.core.i18n import _
from mailman.interfaces.mailinglist import IAcceptableAliasSet
from mailman.interfaces.rules import IRule
class ImplicitDestination:
"""The implicit destination rule."""
implements(IRule)
name = 'implicit-dest'
description = _('Catch messages with implicit destination.')
record = True
def check(self, mlist, msg, msgdata):
"""See `IRule`."""
# Implicit destination checking must be enabled in the mailing list.
if not mlist.require_explicit_destination:
return False
# Messages gated from NNTP will always have an implicit destination so
# are never checked.
if msgdata.get('fromusenet'):
return False
# Calculate the list of acceptable aliases. If the alias starts with
# a caret (i.e. ^), then it's a regular expression to match against.
aliases = set()
alias_patterns = set()
# Adapt the mailing list to the appropriate interface.
alias_set = IAcceptableAliasSet(mlist)
for alias in alias_set.aliases:
if alias.startswith('^'):
alias_patterns.add(alias)
else:
aliases.add(alias)
# Add the list's posting address, i.e. the explicit address, to the
# set of acceptable aliases.
aliases.add(mlist.posting_address)
# Look at all the recipients. If the recipient is any acceptable
# alias (or the explicit posting address), then this rule does not
# match. If not, then add it to the set of recipients we'll check
# against the alias patterns later.
recipients = set()
for header in ('to', 'cc', 'resent-to', 'resent-cc'):
for fullname, address in getaddresses(msg.get_all(header, [])):
address = address.lower()
if address in aliases:
return False
recipients.add(address)
# Now for all alias patterns, see if any of the recipients matches a
# pattern. If so, then this rule does not match.
for pattern in alias_patterns:
escaped = re.escape(pattern)
for recipient in recipients:
try:
if re.match(pattern, recipient, re.IGNORECASE):
return False
except re.error:
# The pattern is a malformed regular expression. Try
# matching again with the pattern escaped.
try:
if re.match(escaped, recipient, re.IGNORECASE):
return False
except re.error:
pass
# Nothing matched.
return True
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