What does "sanitize inputs" even mean? What do you do with a backslash? What do you do with a "? What do you do with weird unicode? What properties does your "s

What does "sanitize inputs" even mean? What do you do with a backslash? What do you do with a "? What do you do with weird unicode? What properties does your "sanitized" input actually have? The meaning of "sane" depends on where you're sending it to. A backslash is a perfectly reasonable character, for instance. Put it in the wrong place in a SQL string and you have bad news. Put a ' in the wrong place in a shell command, sometimes nothing bad happens, other times you get pwned. The right way to escape strange characters is different if you're sending it to an SQL engine, or writing it into a JSON string, or into some HTML, etc.