New submission from Manuel Jacob <m...@manueljacob.de>:
On Python 2, it was possible to recover a percent-encoded byte:
>>> from urllib import url2pathname
>>> url2pathname('%ff')
'\xff'
On Python 3, the byte is decoded using the utf-8 encoding and the "replace"
error handler (therefore there’s no way to recover the byte):
>>> from urllib.request import url2pathname
>>> url2pathname('%ff')
'�'
For my use case (getting the pathname as bytes), it would be sufficient to
specify a different encoding (e.g. latin-1) or a different error handler (e.g.
surrogateescape) that makes it possible to recover the byte by encoding the
result of url2pathname() such that it roundtrips with the encoding and error
handler internally used by url2pathname() for percent-encoded bytes.
I’m not simply sending a patch, because this might point to a deeper issue.
Suppose there’s the following script:
import sys
from pathlib import Path
from urllib.request import urlopen
path = Path(sys.argv[1])
path.write_text('Hello, World!')
with urlopen(path.as_uri()) as resp:
print(resp.read())
If I call this script with b'/tmp/\xff' as the argument, it fails with the
following traceback:
Traceback (most recent call last):
File "/usr/lib/python3.8/urllib/request.py", line 1507, in open_local_file
stats = os.stat(localfile)
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/�'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "test_url2pathname.py", line 6, in <module>
with urlopen(path.as_uri()) as resp:
File "/usr/lib/python3.8/urllib/request.py", line 222, in urlopen
return opener.open(url, data, timeout)
File "/usr/lib/python3.8/urllib/request.py", line 525, in open
response = self._open(req, data)
File "/usr/lib/python3.8/urllib/request.py", line 542, in _open
result = self._call_chain(self.handle_open, protocol, protocol +
File "/usr/lib/python3.8/urllib/request.py", line 502, in _call_chain
result = func(*args)
File "/usr/lib/python3.8/urllib/request.py", line 1485, in file_open
return self.open_local_file(req)
File "/usr/lib/python3.8/urllib/request.py", line 1524, in open_local_file
raise URLError(exp)
urllib.error.URLError: <urlopen error [Errno 2] No such file or directory:
'/tmp/�'>
So maybe urllib.request.url2pathname() should use the same encoding and error
handler as os.fsencode() / os.fsdecode().
----------
components: Library (Lib)
messages: 371537
nosy: mjacob
priority: normal
severity: normal
status: open
title: Can’t configure encoding used by urllib.request.url2pathname()
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Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue40983>
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