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@@ -1,23 +1,50 @@
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-from datetime import datetime, timedelta
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+import time
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+from collections import OrderedDict
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-class ExpiredDict(dict):
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+
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+class ExpiredDict(OrderedDict):
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def __init__(self, expires_in_seconds):
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super().__init__()
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+ # 存储键值对的生存时间
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self.expires_in_seconds = expires_in_seconds
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+ # 获取当前时间的函数
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+ self.now = time.monotonic
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def __getitem__(self, key):
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- value, expiry_time = super().__getitem__(key)
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- if datetime.now() > expiry_time:
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+ # 检查键是否存在
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+ if key not in self:
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+ raise KeyError(key)
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+ # 获取值和过期时间
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+ value, expiry_time = self[key]
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+ # 如果过期时间早于当前时间,删除该键值对并引发 KeyError
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+ if expiry_time is not None and self.now() > expiry_time:
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del self[key]
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- raise KeyError("expired {}".format(key))
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- self.__setitem__(key, value)
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+ raise KeyError(key)
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+ # 如果存活时间不为 None,更新该键值对的过期时间
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+ if self.expires_in_seconds is not None:
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+ self[key] = value, self.now() + self.expires_in_seconds
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+ # 删除过期的键值对
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+ self._delete_expired_items()
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+ # 返回值
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return value
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def __setitem__(self, key, value):
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- expiry_time = datetime.now() + timedelta(seconds=self.expires_in_seconds)
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- super().__setitem__(key, (value, expiry_time))
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+ # 如果存活时间不为 None,设置该键值对的过期时间
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+ if self.expires_in_seconds is not None:
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+ self[key] = value, self.now() + self.expires_in_seconds
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+ else:
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+ self[key] = value, None
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+ # 删除过期的键值对
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+ self._delete_expired_items()
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+
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def get(self, key, default=None):
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try:
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return self[key]
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except KeyError:
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- return default
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+ return default
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+
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+ def _delete_expired_items(self):
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+ # 遍历所有键值对,删除过期的键值对
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+ for key, (value, expiry_time) in list(self.items()):
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+ if expiry_time is not None and self.now() > expiry_time:
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+ del self[key]
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