Added a custom QuerySet subclass to handle cache clearing for Navigation mass updates...

diff --git a/contrib/navigation/models.py b/contrib/navigation/models.py
index 91b2147..e43e8d9 100644 (file)
--- a/contrib/navigation/models.py
+++ b/contrib/navigation/models.py
@@ -6,18 +6,35 @@ from django.forms.models import model_to_dict
 from philo.models import TreeEntity, JSONField, Node, TreeManager
 from philo.validators import RedirectValidator
 
-#from mptt.templatetags.mptt_tags import cache_tree_children
-
 
 DEFAULT_NAVIGATION_DEPTH = 3
 
 
+class NavigationQuerySet(models.query.QuerySet):
+       """
+       This subclass is necessary to trigger cache clearing for Navigation when a mass update
+       or deletion is performed. For now, either action will trigger a clearing of the entire
+       navigation cache, since there's no convenient way to iterate over the changed or
+       deleted instances.
+       """
+       def update(self, *args, **kwargs):
+               super(NavigationQuerySet, self).update(*args, **kwargs)
+               Navigation.objects.clear_cache()
+       
+       def delete(self, *args, **kwargs):
+               super(NavigationQuerySet, self).delete(*args, **kwargs)
+               Navigation.objects.clear_cache()
+
+
 class NavigationManager(TreeManager):
        
        # Analagous to contenttypes, cache Navigation to avoid repeated lookups all over the place.
        # Navigation will probably be used frequently.
        _cache = {}
        
+       def get_queryset(self):
+               return NavigationQuerySet(self.model, using=self._db)
+       
        def closest_navigation(self, node):
                """
                Returns the set of Navigation objects for a given node's navigation. This
@@ -91,10 +108,6 @@ class NavigationManager(TreeManager):
                """
                Clear out the navigation cache. This needs to happen during database flushes
                or if a navigation entry is changed to prevent caching of outdated navigation information.
-               
-               TODO: call this method from update() and delete()! - But how? Those aren't methods available
-               from the manager. The only solution would be to make a special QuerySet subclass that calls
-               this method for each instance.
                """
                if navigation is None:
                        self.__class__._cache.clear()