Extender la clase EmailMessage para utilizar las plantillas

email_temaplte.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from django.template.loader import get_template
from django.template.loader_tags import BlockNode
from django.template import Context
from django.core import mail

class EmailMessage(mail.EmailMultiAlternatives):

    """
    Extender la clase EmailMessage para utilizar las plantillas

    {% block subject %}
    Hola {{ user.name }}
    {% endblock %}
    
    {% block body %}
    Mensaje plano.
    {% endblock %}
    
    {% block html %}
    mensaje <strong>html</strong>.
    {% endblock %}
    

    # from_email = "Me <sender@email.com>"
    # context = {}
    # message = EmailMessage('email/basic.html', context, None, None, from_email, to=[email])
    # message.attach_file('/home/vic/pgadmin.log')
    # message.send()
    """

    def __init__(self, template_name, context, *args, **kwargs):
        self._subject = None
        self._body = None
        self._html = None
        self.template_name = template_name
        self.context = context
        super(mail.EmailMultiAlternatives, self).__init__(*args, **kwargs)
        self.alternatives = []

    @property
    def template_name(self):
        return self._template_name

    @template_name.setter
    def template_name(self, value):
        self._template_name = value
        # Load the template.
        self.template = get_template(self._template_name)

    @property
    def template(self):
        return self._template

    @template.setter
    def template(self, value):
        self._template = value
        for block in self._template.nodelist:
            if isinstance(block, BlockNode):
                if block.name == 'subject':
                    self._subject = block
                elif block.name == 'body':
                    self._body = block
                if block.name == 'html':
                    self._html = block

    def send(self, *args, **kwargs):
        context = Context(self.context)
        if self._subject is not None:
            self.subject = self._subject.render(context).strip('\n\r')
        if self._body is not None:
            self.body = self._body.render(context).strip('\n\r')
        if self._html is not None:
            html = self._html.render(context).strip('\n\r')
            if html:
                if not self.body:
                    self.body = html
                    self.content_subtype = 'html'
                else:
                    self.attach_alternative(html, 'text/html')
        return super(mail.EmailMultiAlternatives, self).send(*args, **kwargs)

    def __getstate__(self):
        return dict((k, v) for k, v in self.__dict__.iteritems()
                    if not k in ('_body', '_html', '_subject', '_template'))

    def __setstate__(self, state):
        self.__dict__ = state
        self.template_name = self._template_name