基于贾斯汀莉莉的回答,我创建了一个自定义管理器,它将post_save信号绑定到类的每个孩子,无论是否抽象。
这是一次性的,测试不当的代码,所以要小心!尽管如此,它仍然有效。
在此示例中,我们允许抽象模型将CachedModelManager定义为管理器,然后将基本高速缓存功能扩展到模型及其子级。它允许您定义每次保存时应删除的易失性密钥列表(因此是post_save信号),并添加一些辅助函数来生成缓存密钥,以及检索,设置和删除密钥。
这当然假设您有一个缓存后端设置并正常工作。
# helperapp\models.py
# -*- coding: UTF-8
from django.db import models
from django.core.cache import cache
class CachedModelManager(models.Manager):
def contribute_to_class(self, model, name):
super(CachedModelManager, self).contribute_to_class(model, name)
setattr(model, 'volatile_cache_keys',
getattr(model, 'volatile_cache_keys', []))
setattr(model, 'cache_key', getattr(model, 'cache_key', cache_key))
setattr(model, 'get_cache', getattr(model, 'get_cache', get_cache))
setattr(model, 'set_cache', getattr(model, 'set_cache', set_cache))
setattr(model, 'del_cache', getattr(model, 'del_cache', del_cache))
self._bind_flush_signal(model)
def _bind_flush_signal(self, model):
models.signals.post_save.connect(flush_volatile_keys, model)
def flush_volatile_keys(sender, **kwargs):
instance = kwargs.pop('instance', False)
for key in instance.volatile_cache_keys:
instance.del_cache(key)
def cache_key(instance, key):
if not instance.pk:
name = "%s.%s" % (instance._meta.app_label, instance._meta.module_name)
raise models.ObjectDoesNotExist("Can't generate a cache key for " +
"this instance of '%s' " % name +
"before defining a primary key.")
else:
return "%s.%s.%s.%s" % (instance._meta.app_label,
instance._meta.module_name,
instance.pk, key)
def get_cache(instance, key):
result = cache.get(instance.cache_key(key))
return result
def set_cache(instance, key, value, timeout=60*60*24*3):
result = cache.set(instance.cache_key(key), value, timeout)
return result
def del_cache(instance, key):
result = cache.delete(instance.cache_key(key))
return result
# myapp\models.py
from django.contrib.auth.models import User
from django.db import models
from helperapp.models import CachedModelManager
class Abstract(models.Model):
creator = models.ForeignKey(User)
cache = CachedModelManager()
class Meta:
abstract = True
class Community(Abstract):
members = models.ManyToManyField(User)
volatile_cache_keys = ['members_list',]
@property
def members_list(self):
result = self.get_cache('members_list')
if not result:
result = self.members.all()
self.set_cache('members_list', result)
return result
修补程序欢迎!
我明白这个背后的想法,但是你可以用一个例子来阐述一下吗?这将有助于保持我目前项目的干爽。 – 2012-05-15 14:47:39
编辑:我试着在你自己的答案中提出你的建议..它适用于我,但我不是100%确定! – 2012-05-15 16:29:33
没有官方的文档'contribute_to_class' ... – Raffi 2017-11-13 08:48:30