How to set private class to form validation callback in codeigniter - php

Question

Suppose this is my controller. (copied from CI documentation)
<?php
class Form extends CI_Controller {
public function index()
{
$this->load->helper(array('form', 'url'));
$this->load->library('form_validation');
$this->form_validation->set_rules('username', 'Username', 'callback_username_check');
$this->form_validation->set_rules('password', 'Password', 'required');
$this->form_validation->set_rules('passconf', 'Password Confirmation', 'required');
$this->form_validation->set_rules('email', 'Email', 'required|is_unique[users.email]');
if ($this->form_validation->run() == FALSE)
{
$this->load->view('myform');
}
else
{
$this->load->view('formsuccess');
}
}
public function username_check($str)
{
if ($str == 'test')
{
$this->form_validation->set_message('username_check', 'The %s field can not be the word "test"');
return FALSE;
}
else
{
return TRUE;
}
}
}
?>
But username_check($str) function is public. According to CI documentation if i want to make a private method I need to add "_" like this.
private function _utility()
{
// some code
}
But how can I set username_check() as private and callback from form validation set_rules?
Should i use DOUBLE underscore "__" i.e callback__username_check?

Answer 1

You can just declare your private function as you have already done:
function _username_check()
{
// some code
}
And in the validation rule, use:
callback__username_check
As I have seen, this must work just fine!
Remember:
The _ prefix would take care of your function privacy, so you do not really have to use the keyword private to declare the function to let the form_validation class access to that function!