Check if attachments with special characters are handled correctly

[RussH]

On an older version of opencats, attachments with special characters are unable to be found after upload as resume's. Check behaviour on current version.

[xalt7x]

I'm interested in this. Any chance to find exact file names with special characters?
I've recently tested some special characters that are unsafe for Windows but usable on Linux:
: * ? " < > |
quotes (") get converted to %22.
Other character are removed from the base file name (or rather replaced with space, unless the special character is not the first in the file name). I don't like that extra "spaces", so I replace them with an underscore (openCATS currently handles non-ASCII characters in a similar fashion).

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Also, I'd like to know opinions of non-Latin characters in file names. As I mentioned above, OpenCATS accepts only 32-127 ASCII characters (Latin ones) for file names. So unfortunately if user uploads file named "резюме.docx" (with Cyrillic characters), it will be saved as "______.docx".

To avoid this, I have to either remove this limit or increase it to 247 characters.

The other approach is to transliterate characters. The downside will be the difference between displayed names (saved in database with original names) and downloadable transliterated file names on disk, so in this case I'd rather transliterate earlier (e.g. , $originalFilename and $newFileName) to rename both.