Display flashdata message in codeigniter callback function - php

Question

I've this registration function and the related callback to check if an username already exists in the database. It works all perfectly, but I have problems with flashdata message
Here's the code:
/*
* Checks registration
*/
public function verify(){
$this->form_validation->set_rules('nome', 'Nome', 'trim|required|min_length[2]|xss_clean');
$this->form_validation->set_rules('cognome', 'Cognome', 'trim|required|min_length[2]|xss_clean');
$this->form_validation->set_rules('username', 'Username', 'trim|required|min_length[4]|xss_clean|callback_check_username');
$this->form_validation->set_rules('email', 'Email', 'trim|required|valid_email');
$this->form_validation->set_rules('password', 'Password', 'trim|required|min_length[4]|max_length[32]');
$this->form_validation->set_rules('password_conf', 'Password Confirmation', 'trim|required|matches[password]');
if($this->form_validation->run() == FALSE)
{
$this->session->set_flashdata('error_reg', 'Something goes wrong, please check your registration form');
redirect('registration');
}
else
{
$this->registration_m->add_user();
$this->session->set_flashdata('success_reg', 'Registration Successful!');
redirect('registration');
}
}
public function check_username($username){
$result = $this->registration_m->check_username_m($username);
if ($result) {
$this->session->set_flashdata('username', 'Username già in uso, riprovare.');
return false;
} else {
return true;
}
}
As you can see there's a redirect on the function verify(), and the flashdata before is correctly shown in case of errors.
My Question is: is there a way to show (in case of error) the flashdata inside the callback function without changing the logic of this piece of code?
Hope I was clear at all, cheers.

Answer 1

Modify your code as below
public function check_username($username){
$result = $this->registration_m->check_username_m($username);
if ($result) {
$this->form_validation->set_message('check_username', 'The %s field can not be the empty');
return false;
} else {
return true;
}
}
See differences in code
$this->session->set_flashdata('username', 'Username già in uso, riprovare.');
$this->form_validation->set_message('check_username', 'The %s field can not be the empty');