urllib.request.url2pathname() mishandles colons in URLs on Windows

@eryksun

Bug report

Bug description:

On Windows, urllib.request.url2pathname() has overly simplistic handling of DOS drives in URLs.

>>> from urllib.request import url2pathname
>>> url2pathname('//host/share/spam.txt:eggs')
'T:\\eggs'  # expected: r'\\host\share\spam.txt:eggs'

Also:

>>> url2pathname('///c:/spam.txt:eggs')
OSError: Bad URL: ///c|/spam.txt|eggs  # expected: r'c:\spam.txt:eggs'

CPython versions tested on:

CPython main branch

Operating systems tested on:

Windows

Linked PRs

GH-126367: Fix urllib.request.url2pathname() colon handling in URLs on Windows #127728
GH-126367: Fix urllib.request.url2pathname() colon handling in URLs on Windows #127752
GH-126367: url2pathname(): handle NTFS alternate data streams #131428

Hi, could this be assigned to me? I'm an undergrad working to make an open source contribution to a software library. Thanks!

Hey, yes that's absolutely fine, thank you for offering! A couple of pointers:

You might want to wait for GH-126212: Fix removal of slashes in file URIs on Windows #126214 to land first
You probably want to use urllib.parse.urlsplit(), or some other urllib function, to split the URL authority and path.

I should also note the Python Dev Guide's Lifecycle of a Pull Request guide :)

Thank you! Will check it out.

Just FYI, the PR I mentioned previously has now landed, so feel free to have a crack at solving this issue! Let me know if you need a hand.

@samtstephens

Hey @samtstephens, if you need a hint, you could look at this code in pathlib:

cpython/Lib/pathlib/_local.py

Lines 909 to 920 in 307c633

    
           if path[:3] == '///': 
        
               # Remove empty authority 
        
               path = path[2:] 
        
           elif path[:12] == '//localhost/': 
        
               # Remove 'localhost' authority 
        
               path = path[11:] 
        
           if path[:3] == '///' or (path[:1] == '/' and path[2:3] in ':|'): 
        
               # Remove slash before DOS device/UNC path 
        
               path = path[1:] 
        
           if path[1:2] == '|': 
        
               # Replace bar with colon in DOS drive 
        
               path = path[:1] + ':' + path[2:]

I think it does roughly what we want to happen in nturl2path.url2pathname() :)

Thanks! Me and my partner are trying this out!

pythonGH-126367: `url2pathname()`: handle NTFS alternate data streams

GH-126367: `url2pathname()`: handle NTFS alternate data streams (#131428

Fixed in 3.14. Given this was reported internally and the fix is somewhat risky, I'll skip backporting. Happy to revisit if anyone wants.

pythonGH-126367: `url2pathname()`: handle NTFS alternate data streams (…

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urllib.request.url2pathname() mishandles colons in URLs on Windows #126367

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CPython versions tested on:

Operating systems tested on:

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	if path[:3] == '///':
	# Remove empty authority
	path = path[2:]
	elif path[:12] == '//localhost/':
	# Remove 'localhost' authority
	path = path[11:]
	if path[:3] == '///' or (path[:1] == '/' and path[2:3] in ':\|'):
	# Remove slash before DOS device/UNC path
	path = path[1:]
	if path[1:2] == '\|':
	# Replace bar with colon in DOS drive
	path = path[:1] + ':' + path[2:]

urllib.request.url2pathname() mishandles colons in URLs on Windows #126367

Description

Bug report

Bug description:

CPython versions tested on:

Operating systems tested on:

Linked PRs

Activity

samtstephens commented on Nov 3, 2024

barneygale commented on Nov 4, 2024

barneygale commented on Nov 4, 2024

samtstephens commented on Nov 7, 2024

barneygale commented on Nov 8, 2024

barneygale commented on Nov 24, 2024

samtstephens commented on Nov 25, 2024

barneygale commented on Mar 18, 2025

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