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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 Generator, 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() -> Generator[None, None, 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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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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