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@@ -1,50 +1,28 @@ |
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import time |
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from collections import OrderedDict |
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class ExpiredDict(OrderedDict): |
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class ExpiredDict(dict): |
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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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# 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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value, expiry_time = super().__getitem__(key) |
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# 如果元素已过期,则从字典中删除该元素并抛出 KeyError 异常 |
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if time.monotonic() > expiry_time: |
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del self[key] |
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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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raise KeyError("expired {}".format(key)) |
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return value |
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def __setitem__(self, key, value): |
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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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# 如果元素已存在,则不需要重新计算过期时间 |
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if key in self: |
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super().__setitem__(key, (value, self[key][1])) |
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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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super().__setitem__(key, (value, time.monotonic() + self.expires_in_seconds)) |
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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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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] |