Cache clearing on object deletion or update

core/apps.py

@@ -34,6 +34,7 @@ class SithConfig(AppConfig):
 
     def ready(self):
         from forum.models import Forum
+        import core.signals
 
         def clear_cached_memberships(**kwargs):
             Forum._club_memberships = {}
@@ -44,4 +45,3 @@ class SithConfig(AppConfig):
             weak=False,
             dispatch_uid="clear_cached_memberships",
         )
-        # TODO: there may be a need to add more cache clearing

core/signals.py

@@ -0,0 +1,54 @@
+# -*- coding:utf-8 -*
+#
+# Copyright 2023
+# - Maréchal <thgirod@hotmail.com>
+#
+# Ce fichier fait partie du site de l'Association des Étudiants de l'UTBM,
+# http://ae.utbm.fr.
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License a published by the Free Software
+# Foundation; either version 3 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Sofware Foundation, Inc., 59 Temple
+# Place - Suite 330, Boston, MA 02111-1307, USA.
+#
+#
+
+
+from django.core.cache import cache
+from django.db.models.signals import pre_delete, pre_save
+from django.dispatch import receiver
+
+from club.models import Club, Membership
+from core.models import Group
+
+
+@receiver(pre_delete, sender=Club, dispatch_uid="clear_cached_memberships")
+def clear_cached_memberships(sender, instance: Club, **_kwargs):
+    """
+    When a club is deleted, clear the cache of the memberships
+    associated with this club
+    """
+    for membership in instance.members.ongoing():
+        cache.delete(f"membership_{membership.club.id}_{membership.user.id}")
+
+
+@receiver(
+    pre_delete,
+    sender=Group,
+    dispatch_uid="clear_cached_user_groups",
+)
+def clear_cached_user_groups(sender, instance: Group, **_kwargs):
+    """
+    When the membership of a user is deleted or edited, clear the associated cache
+    """
+    cache.delete(f"sith_group_{instance.id}")
+    cache.delete(f"sith_group_{instance.name.replace(' ', '_')}")