我正在尝试使模型post_save
上的视图级缓存失效(通过https://docs.djangoproject.com/en/1.3/topics/cache/?from=olddocs#the-per-view-cache设置)。我做了一些谷歌搜索,并在SO Expire a view-cache in Django?找到了这个答案,但它对我不起作用。
我在freenode的#django房间里问过,并且大家一致认为这可能是由于the recent caching changes made in 1.3
有没有人知道如何清除关键模型get_absolute_url()
的缓存条目?
答案 0 :(得分:3)
欢呼ilvar让我指向正确的方向。我的实现如下。我创建了一个名为cache_key
的属性,并将一个post_save接收器添加到模型的子类中,这些模型的视图级缓存在更新后需要清除。欢迎提出改进建议!
from django.conf import settings
from django.core.cache import cache
from django.db.models.signals import post_save
from django.http import HttpRequest
from django.utils.cache import _generate_cache_header_key
from someapp.models import BaseModelofThisClass
class SomeModel(BaseModelofThisClass):
...
@property
def cache_key(self):
# Create a fake request object
request = HttpRequest()
# Set the request method
request.method = "GET"
# Set the request path to be this object's permalink.
request.path = self.get_absolute_url()
# Grab the key prefix (if it exists) from settings
key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
# Generate this object's cache key using django's key generator
key = _generate_cache_header_key(key_prefix, request)
# This is a bit hacky but necessary as I don't know how to do it
# properly otherwise. While generating a cache header key, django
# uses the language of the HttpRequest() object as part of the
# string. The fake request object, by default, uses
# settings.LANGUAGE_CODE as it's language (in my case, 'en-us')
# while the true request objects that are used in building views
# use settings.LANGUAGES ('en'). Instead of replacing the segment
# of the string after the fact it would be far better create a more
# closely mirrored HttpRequest() object prior to passing it to
# _generate_cache_header_key().
key = key.replace(settings.LANGUAGE_CODE, settings.LANGUAGES[settings.DEFAULT_LANGUAGE][0])
return key
@receiver(post_save)
def clear_cache_for_this_item(sender, instance, **kwargs):
# If this is a sub-class of another model
if sender not in BaseModelofThisClass.__subclasses__():
return
else:
cache.delete(instance.cache_key)
答案 1 :(得分:2)
Django的缓存中间件正在使用this为请求生成缓存密钥。因此,您可以使用所需路径制作假request
并获取缓存密钥。然后只需将其从缓存中删除即可。
P.S。 cache_page
装饰器也使用那些中间件,所以它应该以相同的方式工作。