python convert string to safe filename

to_filename.py

"""
Url: https://gist.github.com/wassname/1393c4a57cfcbf03641dbc31886123b8
"""
import unicodedata
import string

valid_filename_chars = "-_.() %s%s" % (string.ascii_letters, string.digits)
char_limit = 255

def clean_filename(filename, whitelist=valid_filename_chars, replace=' '):
    # replace spaces
    for r in replace:
        filename = filename.replace(r,'_')
    
    # keep only valid ascii chars
    cleaned_filename = unicodedata.normalize('NFKD', filename).encode('ASCII', 'ignore').decode()
    
    # keep only whitelisted chars
    cleaned_filename = ''.join(c for c in cleaned_filename if c in whitelist)
    if len(cleaned_filename)>char_limit:
        print("Warning, filename truncated because it was over {}. Filenames may no longer be unique".format(char_limit))
    return cleaned_filename[:char_limit]    

# test
s='fake_folder/\[]}{}|~`"\':;,/? abcABC 0123 !@#$%^&*()_+ clᐖﯫⅺຶ 讀ϯՋ㉘ ⅮRㇻᎠ⍩ 𝁱C ℿ؛ἂeuឃC ᅕ ᑉﺜͧ bⓝ s⡽Հᛕ\ue063 牢𐐥er ᐛŴ n წş .ھڱ                                 df                                         df                                  dsfsdfgsg!zip'
clean_filename(s) # 'fake_folder_abcABC_0123_____clxi_28_DR_C_euC___bn_s_er_W_n_s_.zip'

You could perhaps truncate the filename to 255 characters to make it safe for Windows.

Here's a description on how to overcome the 255-chars limit:
https://stackoverflow.com/questions/36219317/pathname-too-long-to-open/36237176

There one can find a summary and also links to Microsoft describing the reasoning behind that.