The form validation library seems to only work on POST. I need to use query strings and would like to use CI to validate the passed values. Is there a way to do this?
The current Codeigniter 3.0 development branch provides an option to insert your own variable instead of $_POST. So you could start using 3.0.
Alternatively, the only way in CI2.1 is to do $_POST=$_GET before you run the validation.