/** * A validation callback for making sure usernames aren't re-used * @param string $email * @return bool */ public function username_check($username) { $this->load->model('contributor'); $this->load->library('form_validation'); if (!Contributor::findByUsername($username)) { return true; } $this->form_validation->set_message('username_check', 'This username has already been used'); return FALSE; }