56 lines
1.9 KiB
Python
56 lines
1.9 KiB
Python
import codecs
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import sys
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import typing as t
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import warnings
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# We do not trust traditional unixes.
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has_likely_buggy_unicode_filesystem = (
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sys.platform.startswith("linux") or "bsd" in sys.platform
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)
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def _is_ascii_encoding(encoding: t.Optional[str]) -> bool:
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"""Given an encoding this figures out if the encoding is actually ASCII (which
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is something we don't actually want in most cases). This is necessary
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because ASCII comes under many names such as ANSI_X3.4-1968.
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"""
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if encoding is None:
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return False
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try:
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return codecs.lookup(encoding).name == "ascii"
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except LookupError:
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return False
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class BrokenFilesystemWarning(RuntimeWarning, UnicodeWarning):
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"""The warning used by Werkzeug to signal a broken filesystem. Will only be
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used once per runtime."""
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_warned_about_filesystem_encoding = False
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def get_filesystem_encoding() -> str:
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"""Returns the filesystem encoding that should be used. Note that this is
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different from the Python understanding of the filesystem encoding which
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might be deeply flawed. Do not use this value against Python's string APIs
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because it might be different. See :ref:`filesystem-encoding` for the exact
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behavior.
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The concept of a filesystem encoding in generally is not something you
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should rely on. As such if you ever need to use this function except for
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writing wrapper code reconsider.
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"""
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global _warned_about_filesystem_encoding
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rv = sys.getfilesystemencoding()
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if has_likely_buggy_unicode_filesystem and not rv or _is_ascii_encoding(rv):
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if not _warned_about_filesystem_encoding:
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warnings.warn(
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"Detected a misconfigured UNIX filesystem: Will use"
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f" UTF-8 as filesystem encoding instead of {rv!r}",
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BrokenFilesystemWarning,
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)
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_warned_about_filesystem_encoding = True
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return "utf-8"
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return rv
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