A python dictionary where the items timeout after self.timeout seconds

cacheddict.py

import time
  

class CachedDict(object):
    """A dictionary where the items timeout after self.timeout seconds

    We've implemented just enough of a real dictionary to work as a
    replacement for the dicts in django.template.loader.cached.Loader

    """
    def __init__(self, *args, **kwargs):
        self.data = {}
        try:
            self.timeout = kwargs['timeout']
        except KeyError:
            self.timeout = 300  # 5 min

    def __setitem__(self, key, value):
        timestamp = int(time.time())
        self.data[key] = (timestamp, value)

    def __getitem__(self, key):
        now = int(time.time())
        timestamp, value = self.data[key]
        if now - timestamp > self.timeout:
            del self.data[key]
            raise KeyError(key)
        return value

    def get(self, key, default=None):
        try:
            return self.__getitem__(key)
        except KeyError:
            return default

    def clear(self):
        self.data.clear()