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

[HGStyle]

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 !

[ericvsmith]

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.

[zware]

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 '').