email.py

import os

from django.conf import settings
from django.core.mail.message import EmailMultiAlternatives
from django.template.base import TemplateDoesNotExist
from django.template.loader import render_to_string


def email_from_template(template_dir, ctx=None, from_email=None, to=None):
    """Generate an Email message from a set of templates

    An email is generated by rendering the following templates in the provided
    template directory using the provided context (ctx):

        - body.txt (text body)
        - body.html (full html body)
        - subject.txt (text subject)

    The subject.txt and body.html must always be included. If body.txt is not
    included, body.html is used. This is bad! BE SURE TO INCLUDE A TEXT
    TEMPLATE FOR ACCESSIBILITY.

    Note: the message is NOT sent.
    """
    if ctx is None:
        ctx = {}

    _rel = lambda *parts: os.path.join(template_dir, *parts)

    subject = render_to_string(_rel('subject.txt'), ctx)
    # Subject cannot have newlines
    subject = subject.replace('\n', '').replace('\r', '')

    message = EmailMultiAlternatives(subject, '', from_email, to)

    body_html = render_to_string(_rel('body.html'), ctx)

    try:
        body_txt = render_to_string(_rel('body.txt'), ctx)
    except TemplateDoesNotExist:
        message.content_subtype = 'html'
        message.body = body_html
    else:
        message.body = body_txt
        message.attach_alternative(body_html, 'text/html')

    return message


def send_from_template(template_dir, ctx=None, from_email=None, to=None,
                       fail_silently=False):
    if from_email is None:
        from_email = settings.DEFAULT_FROM_EMAIL
    message = email_from_template(template_dir, ctx, from_email, to)
    return message.send(fail_silently=fail_silently)