Delimiting User Input

Question

What is the best character to use to delimit user input?

For example if a user has an infinite number of textboxes to type things into, but each textbox's value will be concatenated into a single database field, what is the safest character to delimit each input?

I think it should be a character not on your typical keyboard. Is there a character out there just for this?

Answer 1

You could use one of the ASCII control characters. There's one called "Record Separator" which has a hex value of 0x1E that might fit your needs.

Edit: Incidentally, if you want to do a proper job, you should probably ensure that \x1E is escaped in user input. One way to do this would be to use another ASCII control character: \x1B which is the "escape" control code. Thus, "\x1E" in input becomes "\x1B\x1E" and "\x1B" becomes "\x1B\x1B".

Keep in mind, of course, that because these are non-printing control codes, they can't be displayed. If you want a printable representation, you might want to go with a normal character like the comma and just escape it from input.

Answer 2

I guess one approach is to use a comma, and then to escape commas within the user input. It's probably not safe to assume any character (or even a sequence of characters) can't appear in user input -- if you can enter it in your code, then there's a way the user can enter it into a text box!