70 lines
2.1 KiB
Python
70 lines
2.1 KiB
Python
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"""HTTP cache implementation.
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"""
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import os
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from contextlib import contextmanager
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from typing import Iterator, Optional
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from pip._vendor.cachecontrol.cache import BaseCache
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from pip._vendor.cachecontrol.caches import FileCache
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from pip._vendor.requests.models import Response
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from pip._internal.utils.filesystem import adjacent_tmp_file, replace
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from pip._internal.utils.misc import ensure_dir
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def is_from_cache(response: Response) -> bool:
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return getattr(response, "from_cache", False)
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@contextmanager
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def suppressed_cache_errors() -> Iterator[None]:
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"""If we can't access the cache then we can just skip caching and process
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requests as if caching wasn't enabled.
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"""
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try:
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yield
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except OSError:
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pass
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class SafeFileCache(BaseCache):
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"""
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A file based cache which is safe to use even when the target directory may
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not be accessible or writable.
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"""
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def __init__(self, directory: str) -> None:
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assert directory is not None, "Cache directory must not be None."
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super().__init__()
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self.directory = directory
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def _get_cache_path(self, name: str) -> str:
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# From cachecontrol.caches.file_cache.FileCache._fn, brought into our
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# class for backwards-compatibility and to avoid using a non-public
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# method.
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hashed = FileCache.encode(name)
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parts = list(hashed[:5]) + [hashed]
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return os.path.join(self.directory, *parts)
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def get(self, key: str) -> Optional[bytes]:
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path = self._get_cache_path(key)
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with suppressed_cache_errors():
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with open(path, "rb") as f:
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return f.read()
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def set(self, key: str, value: bytes, expires: Optional[int] = None) -> None:
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path = self._get_cache_path(key)
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with suppressed_cache_errors():
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ensure_dir(os.path.dirname(path))
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with adjacent_tmp_file(path) as f:
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f.write(value)
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replace(f.name, path)
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def delete(self, key: str) -> None:
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path = self._get_cache_path(key)
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with suppressed_cache_errors():
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os.remove(path)
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