book titles with invalid characters for filename under windows arise error

[jackjackk]

I have the same problem described here
http://stackoverflow.com/questions/22620965/ioerror-errno-22-invalid-mode-wb-or-filename

I was wondering whether the filename could be normalized, at least under windows, before creating the file with the filename of the title.

For the moment I'm importing unicodedata and using the following verbose code (and not immune to errors, as I allow the \ to be in the filename, as it is used for referring to the partial path) in export_txt to make things work:

        try:
            with open(filename, 'wb') as f:
                f.write("\n\n---\n\n".join(lines))
        except:
            oldfilename = filename
            filename = unicodedata.normalize('NFKD', filename).encode('ascii','ignore')
            valid_chars = '\\-_.() abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
            filename = ''.join(c for c in filename if c in valid_chars)
            print 'Converting', oldfilename, 'to', filename
            with open(filename, 'wb') as f:
                f.write("\n\n---\n\n".join(lines))

Thanks