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mimetypes.guess_extension : AttributeError: 'NoneType' object has no attribute 'lower' #96264

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Closed as not planned
mimetypes.guess_extension : AttributeError: 'NoneType' object has no attribute 'lower'#96264
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type-bugAn unexpected behavior, bug, or error

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@HGStyle
HGStyle
opened on Aug 25, 2022

Hi, when i call the function "guess_extension" from the mimetypes module, i get an error :

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/hg/Bureau/ezConverter/module.py", line 14, in getRealExtension
    currentext = mime.guess_extension(x[0])
  File "/usr/lib/python3.9/mimetypes.py", line 326, in guess_extension
    return _db.guess_extension(type, strict)
  File "/usr/lib/python3.9/mimetypes.py", line 192, in guess_extension
    extensions = self.guess_all_extensions(type, strict)
  File "/usr/lib/python3.9/mimetypes.py", line 171, in guess_all_extensions
    type = type.lower()
AttributeError: 'NoneType' object has no attribute 'lower'

I dont think it's my code. But it is here :

import mimetypes as mime
def getRealExtension(filename):
    x = mime.guess_type(filename)
    currentext = mime.guess_extension(x[0])
# I import it to the shell and call the function.

Thanks in advance !

Activity

  1. HGStyle
    added
    type-bugAn unexpected behavior, bug, or error
    on Aug 25, 2022

  2. ericvsmith commented on Aug 25, 2022

    @ericvsmith
    ericvsmith
    on Aug 25, 2022
    Member

    Your filename Is probably None. If you can provide a small, complete example that we can run then we can take a look at it, otherwise not much we can do.

  3. zware
    added
    pendingThe issue will be closed if no feedback is provided
    on Aug 25, 2022

  4. zware commented on Aug 25, 2022

    @zware
    zware
    on Aug 25, 2022
    Member

    mimetypes.guess_type is documented to return None for the type portion of its return tuple when the type cannot be guessed, and mimetypes.guess_all_extensions (and, thereby, mimetypes.guess_extension) expects a str type argument. There's no bug in the mimetypes module here.

    You could work around this by using mimetypes.guess_extension(mimetypes.guess_type(filename)[0] or '').

  5. zware
    closed this as not plannedon Aug 25, 2022
  6. zware
    removed
    pendingThe issue will be closed if no feedback is provided
    on Aug 25, 2022
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