65 lines
1.8 KiB
Python
65 lines
1.8 KiB
Python
"""diskcache 后端：基于 SQLite 的本地持久化缓存，多进程安全。"""
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from pathlib import Path
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from typing import Any, Iterator
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from diskcache import Cache as DiskCache
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from chongming_cache.backends.base import CacheBackend
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class DiskBackend(CacheBackend):
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"""包装 diskcache.Cache，提供统一接口。
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Args:
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path: 缓存目录（SQLite 数据文件所在目录），父目录不存在时自动创建。
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"""
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def __init__(self, path: str | Path):
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self._cache = DiskCache(path)
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@property
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def client(self) -> DiskCache:
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"""底层 diskcache.Cache 实例（逃生口）。"""
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return self._cache
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def __contains__(self, key) -> bool:
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return key in self._cache
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def __getitem__(self, key) -> Any:
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return self._cache[key]
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def __setitem__(self, key, value) -> None:
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self._cache[key] = value
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def __delitem__(self, key) -> None:
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del self._cache[key]
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def __len__(self) -> int:
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return len(self._cache)
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def __iter__(self) -> Iterator:
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return iter(self._cache)
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def get(self, key, default=None) -> Any:
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return self._cache.get(key, default)
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def set(self, key, value, expire: float | None = None) -> None:
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self._cache.set(key, value, expire=expire)
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def set_nx(self, key, value, expire: float | None = None) -> bool:
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# diskcache.add 仅在 key 不存在时写入，返回是否成功（SET NX 语义）且进程安全
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return bool(self._cache.add(key, value, expire=expire))
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def touch(self, key, expire: float | None = None) -> bool:
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return self._cache.touch(key, expire=expire)
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def delete(self, key) -> bool:
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return self._cache.delete(key)
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def clear(self) -> None:
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self._cache.clear()
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def close(self) -> None:
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self._cache.close()
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