From ae602182bcbeb943d031fbe3c16f2fe464e8e862 Mon Sep 17 00:00:00 2001 From: Stephen Burrows Date: Tue, 4 Jan 2011 11:36:06 -0500 Subject: [PATCH] Added a custom QuerySet subclass to handle cache clearing for Navigation mass updates and deletions. --- contrib/navigation/models.py | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/contrib/navigation/models.py b/contrib/navigation/models.py index 91b2147..e43e8d9 100644 --- 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 This needs to happen during database flushes or if a navigation entry is changed to prevent caching of outdated navigation information.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() -- 2.20.1