Simple django admin command for processing incoming bounce reports

process_bounce_email.py

"""Simple django admin command for processing incoming bounce reports.

This script depends on flufl.bounce_ for processing the bounce reports.  The
flufl packages are a spinoff from the mailman project so are pretty robust and
have good coverage of real-world bounce reports.

You will usually need a small wrapper script to use this with a mail server.
For example to use with sendmail put this in `/etc/smrsh/process_site_bounces`::

    #!/bin/sh
    exec python /path/to/django/project/manage.py process_bounce_email

And then in `/etc/aliases`::

    bounces: |/etc/smrsh/process_site_bounces

You should ensure that your outgoing email uses this `bounces` address as the
`Return-Path`.  For example if using django-ses_, this would be the address
set with `AWS_SES_RETURN_PATH`.


.. _flufl.bounce: https://launchpad.net/flufl.bounce
.. _django-ses: https://github.com/hmarr/django-ses
"""
import sys
import logging
from email import message_from_file
from django.core.management.base import BaseCommand
from flufl.bounce import all_failures


def disable_email(addresses):
    """Disable email for all users with matching addresses."""
    from django.contrib.auth.models import User
    User.objects.filter(email__in=addresses).update(email='')
    for address in addresses:
        logging.warning('Disabled email for %s', address)


class Command(BaseCommand):
    help = "Process incoming bounce reports and disable bouncing addresses."

    def handle(self, *args, **options):
        # Parse email content sent on stdin looking for bounce messages
        # and disable only those addresses found with permanent failure.
        msg = message_from_file(sys.stdin)
        id = msg.get('Message-Id', 'unknown')
        temporary, permanent = all_failures(msg)
        if temporary:
            logging.info('Temporary address failures for message %s: %s',
                                id, ','.join(temporary))
        if permanent:
            logging.info('Permanent address failures for message %s: %s',
                                id, ','.join(permanent))
            disable_email(permanent)