Push modified mail-lists on subscriptions save to DB.

maillists/models.py

@@ -6,6 +6,8 @@ import subprocess
 
 from django.conf import settings
 from django.db import models
+from django.db.models.signals import m2m_changed
+from django.dispatch import receiver
 
 from coin.members.models import Member
 
@@ -42,7 +44,7 @@ class MaillingList(models.Model):
         return '\n'.join(
                 self.subscribers.values_list('email', flat=True))
 
-    def sync_to_list_server(self):
+    def sync_to_list_server(self, force_clear=False):
         if not settings.MAILLIST_SYNC_COMMAND:
             raise ValueError('You should define MAILLIST_SYNC_COMMAND'
                              ' setting to use maillist module')
@@ -54,8 +56,38 @@ class MaillingList(models.Model):
             p = subprocess.Popen(
                 cmd, shell=True,
                 stdin=subprocess.PIPE, stderr=subprocess.PIPE)
-            out_stdout, out_stderr = p.communicate(address_list)
+            if force_clear:
+                text_listing = ''
+            else:
+                text_listing = self.as_text_listing()
+            out_stdout, out_stderr = p.communicate(text_listing)
             if p.returncode != 0:
                 raise SystemError(
                     "Erreur à l'appel de la commande : \"{}\"".format(
-                        out_stderr))
+                        out_stderr.decode('utf-8')))
+
+
+@receiver(m2m_changed, sender=MaillingList.subscribers.through)
+def push_updated_list(sender, instance, action, reverse, model, pk_set, **kwargs):
+    if action in ('post_add', 'post_remove'):
+        if reverse:
+            impacted_mls = MaillingList.objects.filter(pk__in=pk_set)
+        else:
+            impacted_mls = [instance]
+    elif action == 'post_clear' and not reverse:
+        impacted_mls = [instance]
+
+    # cannot be handled at post_clear (we would have lost the information on
+    # what has been removed)
+    elif action == 'pre_clear' and reverse:
+        impacted_mls = instance.subscribed_maillinglists.all()
+
+    else:
+        return
+
+    for ml in impacted_mls:
+        if action == 'pre_clear':
+            # We have to force it because it has not yet been reflected in DB.
+            ml.sync_to_list_server(force_clear=True)
+        else:
+            ml.sync_to_list_server()