75 lines
1.9 KiB
Python
75 lines
1.9 KiB
Python
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# SPDX-FileCopyrightText: 2015 Eric Larson
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#
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# SPDX-License-Identifier: Apache-2.0
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"""
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The cache object API for implementing caches. The default is a thread
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safe in-memory dictionary.
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"""
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from __future__ import annotations
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from threading import Lock
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from typing import IO, TYPE_CHECKING, MutableMapping
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if TYPE_CHECKING:
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from datetime import datetime
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class BaseCache:
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def get(self, key: str) -> bytes | None:
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raise NotImplementedError()
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def set(
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self, key: str, value: bytes, expires: int | datetime | None = None
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) -> None:
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raise NotImplementedError()
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def delete(self, key: str) -> None:
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raise NotImplementedError()
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def close(self) -> None:
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pass
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class DictCache(BaseCache):
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def __init__(self, init_dict: MutableMapping[str, bytes] | None = None) -> None:
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self.lock = Lock()
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self.data = init_dict or {}
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def get(self, key: str) -> bytes | None:
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return self.data.get(key, None)
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def set(
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self, key: str, value: bytes, expires: int | datetime | None = None
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) -> None:
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with self.lock:
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self.data.update({key: value})
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def delete(self, key: str) -> None:
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with self.lock:
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if key in self.data:
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self.data.pop(key)
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class SeparateBodyBaseCache(BaseCache):
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"""
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In this variant, the body is not stored mixed in with the metadata, but is
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passed in (as a bytes-like object) in a separate call to ``set_body()``.
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That is, the expected interaction pattern is::
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cache.set(key, serialized_metadata)
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cache.set_body(key)
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Similarly, the body should be loaded separately via ``get_body()``.
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"""
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def set_body(self, key: str, body: bytes) -> None:
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raise NotImplementedError()
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def get_body(self, key: str) -> IO[bytes] | None:
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"""
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Return the body as file-like object.
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"""
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raise NotImplementedError()
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