from django.db import models
from django.utils.crypto import get_random_string
from django.core.mail import EmailMessage, get_connection
from django.conf import settings
from django.contrib.contenttypes.fields import GenericForeignKey
from django.contrib.contenttypes.models import ContentType
from django.utils.translation import ugettext_lazy as _
from django.contrib.auth import get_user_model
import hashlib
def generate_message_token():
# /!\ birthday problem
return get_random_string(length=32, allowed_chars='abcdefghijklmnopqrstuvwxyz0123456789')
def hexdigest_sha256(*args):
r = hashlib.sha256()
for arg in args:
r.update(str(arg).encode('utf-8'))
return r.hexdigest()
class MessageCorrespondent(models.Model):
email = models.EmailField()
token = models.CharField(max_length=64, default=generate_message_token, unique=True)
class MessageAuthor(models.Model):
author_type = models.ForeignKey(ContentType, on_delete=models.CASCADE, null=True, blank=True)
author_id = models.PositiveIntegerField(null=True, blank=True)
author = GenericForeignKey('author_type', 'author_id')
token = models.CharField(max_length=64, default=generate_message_token, unique=True)
def __str__(self):
author_class = self.author_type.model_class()
if author_class == get_user_model():
return self.author.get_full_name()
else:
return str(self.author)
class MessageThread(models.Model):
created = models.DateTimeField(auto_now_add=True)
token = models.CharField(max_length=64, default=generate_message_token, unique=True)
class MessageManager(models.Manager):
def get_queyset(self):
qs = super().get_queryset()
# Does not work so well as prefetch_related is limited to one content type for generic foreign keys
qs = qs.prefetch_related('author__author')
return qs
class Message(models.Model):
created = models.DateTimeField(auto_now_add=True)
thread = models.ForeignKey(MessageThread, on_delete=models.CASCADE)
author = models.ForeignKey(MessageAuthor, on_delete=models.PROTECT)
in_reply_to = models.ForeignKey('self', null=True, blank=True, on_delete=models.SET_NULL)
subject = models.CharField(max_length=1000, blank=True)
content = models.TextField(blank=True)
token = models.CharField(max_length=64, default=generate_message_token, unique=True)
objects = MessageManager()
class Meta:
ordering = ['created']
def send_notification(self, sender, dests, reply_to=None, message_id=None, reference=None, footer=None, subject=None):
messages = []
for dest, dest_name, dest_email in dests:
dest_type = ContentType.objects.get_for_model(dest)
dest, _ = MessageAuthor.objects.get_or_create(author_type=dest_type, author_id=dest.pk)
token = self.token + dest.token + hexdigest_sha256(settings.SECRET_KEY, self.token, dest.token)[:16]
if reply_to:
reply_to_name, reply_to_email = reply_to
reply_to_list = ['%s <%s>' % (reply_to_name, reply_to_email.format(token=token))]
else:
reply_to_list = []
headers = dict()
if message_id:
headers.update({
'Message-ID': message_id.format(id=self.token),
})
if message_id and reference:
headers.update({
'References': message_id.format(id=reference),
})
body = self.content
if footer is not None:
body += footer
messages.append(EmailMessage(
subject=subject or self.subject,
body=body,
from_email='%s <%s>' % sender,
to=['%s <%s>' % (dest_name, dest_email)],
reply_to=reply_to_list,
headers=headers,
))
connection = get_connection()
connection.send_messages(messages)
def __str__(self):
return _("Message from %(author)s") % {'author': str(self.author)}
