CachedQuerySet.py

# -*- coding: utf-8 -*-
from django.db import models
from django.core.cache import cache
from django.db.models.query import QuerySet
from utils import key_for_instance


class CachedQuerySet(QuerySet):

    def get_pk(self, kwargs):
        for val in ('pk', 'pk__exact', 'id', 'id__exact'):
            if val in kwargs:
                return kwargs[val]
        return None

    def filter(self, *args, **kwargs):
        pk = self.get_pk(kwargs)
        if pk is not None:
            key = key_for_instance(self.model, pk=pk)
            cache_content = cache.get(key)
            if cache_content is not None:
                self._result_cache = [cache_content]
        return super(CachedQuerySet, self).filter(*args, **kwargs)


class CacheManager(models.Manager):

    def get_queryset(self):
        return CachedQuerySet(self.model)


####################################################


class CacheableModel(models.Model):
    class Meta:
        abstract = True

    def save(self, *args, **kwargs):
        super(CacheableModel, self).save(*args, **kwargs)
        cache.set(key_for_instance(self), self, 60 * 60 * 24)

    def delete(self):
        cache.delete(key_for_instance(self))
        super(CacheableModel, self).delete()

    objects = CacheManager()