menus/models.py
from django.db import models
class CacheKeyManager(models.Manager):
def get_keys(self, site_id=None, language=None):
if not site_id and not language:
# Both site and language are None - return everything
ret = self.all()
elif not site_id:
ret = self.filter(language=language)
elif not language:
ret = self.filter(site=site_id)
else:
# Filter by site_id *and* by language.
ret = self.filter(site=site_id).filter(language=language)
return ret
class CacheKey(models.Model):
"""
This is to store a "set" of cache keys in a fashion where it's accessible
by multiple processes / machines.
Multiple Django instances will then share the keys.
This allows for selective invalidation of the menu trees (per site, per
language), in the cache.
"""
language = models.CharField(max_length=255)
site = models.PositiveIntegerField()
key = models.CharField(max_length=255)
objects = CacheKeyManager()