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- import time
- from collections import OrderedDict
-
-
- class ExpiredDict(OrderedDict):
- def __init__(self, expires_in_seconds):
- super().__init__()
- # 存储键值对的生存时间
- self.expires_in_seconds = expires_in_seconds
- # 获取当前时间的函数
- self.now = time.monotonic
-
- def __getitem__(self, key):
- # 检查键是否存在
- if key not in self:
- raise KeyError(key)
- # 获取值和过期时间
- value, expiry_time = self[key]
- # 如果过期时间早于当前时间，删除该键值对并引发 KeyError
- if expiry_time is not None and self.now() > expiry_time:
- del self[key]
- raise KeyError(key)
- # 如果存活时间不为 None，更新该键值对的过期时间
- if self.expires_in_seconds is not None:
- self[key] = value, self.now() + self.expires_in_seconds
- # 删除过期的键值对
- self._delete_expired_items()
- # 返回值
- return value
-
- def __setitem__(self, key, value):
- # 如果存活时间不为 None，设置该键值对的过期时间
- if self.expires_in_seconds is not None:
- self[key] = value, self.now() + self.expires_in_seconds
- else:
- self[key] = value, None
- # 删除过期的键值对
- self._delete_expired_items()
-
- def get(self, key, default=None):
- try:
- return self[key]
- except KeyError:
- return default
-
- def _delete_expired_items(self):
- # 遍历所有键值对，删除过期的键值对
- for key, (value, expiry_time) in list(self.items()):
- if expiry_time is not None and self.now() > expiry_time:
- del self[key]
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