queue_message for use with django-mailer

mail.py

# queue_message(message, priority="medium")
# Queues an EmailMessage object, in apps using django-mailer.
#   (https://github.com/pinax/django-mailer)
# Respects django-mailer's DontSendEntry blacklist.
# If django-mailer is not loaded, just sends the message immediately.

from django.conf import settings

if "mailer" in settings.INSTALLED_APPS:
    # Sigh. Django-mailer doesn't expose its queuing API in a useful way, so we replicate parts of it here.
    # This is adapted from mailer.send_html_mail
    from mailer import PRIORITY_MAPPING
    from mailer.models import make_message
    def queue_message(message, priority="medium"):
        # need to force_unicode in case fields used lazy version of ugettext
        message.subject = force_unicode(message.subject)
        message.body = force_unicode(message.body)
        queued_msg = make_message(
            subject=message.subject,
            body=message.body,
            from_email=message.from_email,
            to=message.to,
            # cc=message.cc, # BUG: django-mailer doesn't check cc field for DontSendEntry
            bcc=message.bcc,
            priority=PRIORITY_MAPPING[priority])
        # copy back any DontSendEntry recipient filtering from make_message
        message.to = queued_msg.email.to
        message.cc = queued_msg.email.cc
        message.bcc = queued_msg.email.bcc
        queued_msg.email = message
        queued_msg.save()
        return 1
else:
    # No Django-mailer, so just send immediately
    def queue_message(message, priority="medium"):
        return message.send()