Add notifications

features/subscriptions/notifications.py

+from core.notifications import Notification
+
+
 def update_recipients(recipients_dict, association=None, subscriptions=[], contributions=[]):
     def update_attributes(key, **kwargs):
         attributes = recipients_dict.setdefault(key, {})
@@ -13,3 +16,14 @@ def update_recipients(recipients_dict, association=None, subscriptions=[], contr
         update_attributes(contribution.author, contribution=contribution)
     if association and not association.entity.is_group:
         update_attributes(association.entity, association=association)
+
+
+class NoSubscriber(Notification):
+    subject = 'Abonnement'
+
+    def get_formatted_recipient(self):
+        return '<{}>'.format(self.recipient)
+
+
+class Subscriber(Notification):
+    subject = 'Abonnement'

features/subscriptions/templates/subscriptions/nosubscriber.txt

+Jemand hat Deine E-Mail-Adresse auf {{ site.name }} angegeben.
+
+Für Deine E-Mail-Adresse existiert kein Abonnenment der Gruppe {{ object }}.

features/subscriptions/templates/subscriptions/subscriber.txt

+Jemand hat Deine E-Mail-Adresse auf {{ site.name }} angegeben.
+
+Wenn Du Dein Abonnement der Gruppe {{ object }} kündigen möchtest, bestätige dies bitte, indem Du dem folgenden Verweis folgst:
+...

features/subscriptions/views.py

@@ -6,10 +6,11 @@ from django.shortcuts import get_object_or_404
 from django.views.generic import CreateView, DeleteView, FormView
 
 from core.views import PermissionMixin
+from features.gestalten.models import Gestalt
 from features.groups.models import Group
 from features.subscriptions.models import Subscription
 from features.subscriptions.rules import is_subscribed
-from . import forms
+from . import forms, notifications
 
 
 class GroupSubscribe(SuccessMessageMixin, PermissionMixin, CreateView):
@@ -76,7 +77,12 @@ class GroupUnsubscribeRequest(PermissionMixin, FormView):
     template_name = 'subscriptions/delete_request.html'
 
     def form_valid(self, form):
-
+        email = form.cleaned_data['subscriber']
+        try:
+            subscriber = self.group.subscribers.get_by_email(email)
+            notifications.Subscriber(self.group).send(subscriber)
+        except Gestalt.DoesNotExist:
+            notifications.NoSubscriber(self.group).send(email)
         info(self.request, 'Es wurde eine E-Mail an die angebene Adresse versendet.')
         return super().form_valid(form)