How do i escape invalid characters in filenames on multiple FS

Question

How do i escape invalid characters in filenames? I ask this question once before and wrote up a class with the solution. Now i would like to extend it. My site will be able to detect what OS the user is on. So base on that i either 1) Want to escape based on the FS/OS the user is on or 2) Escape it so it works on all filesystems.

What characters may be valid on windows 7 or linux (i am unsure what my current linux FS is set to) and invalid on XP or valid on windows or mac and not on linux?

Answer 1

Will the name of the directory ever be displayed to a user and, if so, does it need to look like the user name (based on info in the other question)? If not, you could split it to a character array, convert the value of each character to its hexadecimal representation and put those together to a string. That should work on any file system.

private static string ToHexString(string input)
{
    return string.Join("", input.ToCharArray()
        .Select(c => string.Format("{0:x}", (int)c))
        .ToArray());
}

Answer 2

solutions

1. Make them [A-Za-z._-] and escape characters that do not fall in the range
2. Choose your supported OS and FS and find out what is illegal or not and support those until further notice