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# Copyright (C) 1998-2011 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/>.
"""Parse RFC 3464 (i.e. DSN) bounce formats.
RFC 3464 obsoletes 1894 which was the old DSN standard. This module has not
been audited for differences between the two.
"""
from __future__ import absolute_import, unicode_literals
__metaclass__ = type
__all__ = [
'DSN',
]
from email.iterators import typed_subpart_iterator
from email.utils import parseaddr
from zope.interface import implements
from mailman.interfaces.bounce import IBounceDetector, NonFatal
def check(msg):
# Iterate over each message/delivery-status subpart.
addresses = []
for part in typed_subpart_iterator(msg, 'message', 'delivery-status'):
if not part.is_multipart():
# Huh?
continue
# Each message/delivery-status contains a list of Message objects
# which are the header blocks. Iterate over those too.
for msgblock in part.get_payload():
# We try to dig out the Original-Recipient (which is optional) and
# Final-Recipient (which is mandatory, but may not exactly match
# an address on our list). Some MTA's also use X-Actual-Recipient
# as a synonym for Original-Recipient, but some apparently use
# that for other purposes :(
#
# Also grok out Action so we can do something with that too.
action = msgblock.get('action', '').lower()
# Some MTAs have been observed that put comments on the action.
if action.startswith('delayed'):
return NonFatal
if not action.startswith('fail'):
# Some non-permanent failure, so ignore this block.
continue
params = []
foundp = False
for header in ('original-recipient', 'final-recipient'):
for k, v in msgblock.get_params([], header):
if k.lower() == 'rfc822':
foundp = True
else:
params.append(k)
if foundp:
# Note that params should already be unquoted.
addresses.extend(params)
break
else:
# MAS: This is a kludge, but SMTP-GATEWAY01.intra.home.dk
# has a final-recipient with an angle-addr and no
# address-type parameter at all. Non-compliant, but ...
for param in params:
if param.startswith('<') and param.endswith('>'):
addresses.append(param[1:-1])
return set(parseaddr(address)[1] for address in addresses
if address is not None)
class DSN:
"""Parse RFC 3464 (i.e. DSN) bounce formats."""
implements(IBounceDetector)
def process(self, msg):
# A DSN has been seen wrapped with a "legal disclaimer" by an outgoing
# MTA in a multipart/mixed outer part.
if msg.is_multipart() and msg.get_content_subtype() == 'mixed':
msg = msg.get_payload()[0]
# The above will suffice if the original message 'parts' were wrapped
# with the disclaimer added, but the original DSN can be wrapped as a
# message/rfc822 part. We need to test that too.
if msg.is_multipart() and msg.get_content_type() == 'message/rfc822':
msg = msg.get_payload()[0]
# The report-type parameter should be "delivery-status", but it seems
# that some DSN generating MTAs don't include this on the
# Content-Type: header, so let's relax the test a bit.
if not msg.is_multipart() or msg.get_content_subtype() <> 'report':
return None
return check(msg)
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