redis自定义缓存

import weakref, collections
import time


class LocalCache():
    notFound = object()

    class Dict(dict):
        def __del__(self):
            pass

    def __init__(self,maxlen=20):
        self.weak = weakref.WeakKeyDictionary()
        self.strong=collections.deque(maxlen=maxlen)

    @staticmethod
    def nowTime():
        return int(time.time())

    def get(self, key):
        # 每个键值对后面加个字段过期时间
        # 第一次获取　expire＝当前时间＋过期时间
        # 非第一次获取时候，expire判断是否过期，过期可认为数据没有找到
        # 过期后应该删除数据
        value = self.weak.get(key, self.notFound)
        # 没有过期
        if (value is not self.notFound):
            expire = value[r'expire']
            # 已经过期
            if (self.nowTime() > expire):
                return self.notFound
            else:
                return value
        # 过期了－返回没有找到
        else:
            return self.notFound
    def set(self,key,value):
        self.weak[key]=strongRef=LocalCache.Dict(value)
        self.strong.append(strongRef)


from functools import wraps


def funcCache(expire=1):
    caches = LocalCache()

    def _wrappend(func):
        @wraps(func)
        def __wrapped(*args, **kwargs):
            # 计算出缓存的key值
            key = str(func) + str(args) + str(kwargs)

            result = caches.get(key)

            if (result is LocalCache.notFound):
                result = func(*args, **kwargs)

                caches.set(key, {r'result': result, r'expire': expire + caches.nowTime()})

                result = caches.get(key)

            return result

        return __wrapped

    return _wrappend
f=funcCache()