how to pass 3 parameters in custom callback() - codeigniter - codeigniter

Question

Config/login_rules.php
Here for the callback function check_email_existence
I want to pass three parameters which are (email,table, field)
<?php
/**
* SETTING VALIDATION RULES FOR THE LOGIN FORM
*/
$config['login_settings'] = array(
array(
'field' => 'password',
'label' => 'Password',
'rules' => 'required|trim|min_length[6]|max_length[20]|xss_clean',
'errors' => array(
'required' => 'You must provide a %s.',
),
),
array(
'field' => 'email',
'label' => 'Email',
'rules' => 'required|trim|valid_email|xss_clean|check_email_existence'
)
);
?>
I have extended the form validation helper libraries/MY_Form_validation.php
<?php
if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class MY_Form_validation extends CI_Form_validation {
protected $CI;
public function __construct($config = array())
{
parent::__construct($config);
$this->CI =& get_instance();
}
function check_email_existence($email,$table,$field) {
$this->CI->form_validation->set_message('check_email_existence', 'This %s id is not registered.');
$query = $this->CI->db->query("SELECT COUNT(*) AS count FROM $table WHERE $field = '".$email."' ");
$row = $query->row();
return ($row->count > 0) ? 'success' : 'failure';
}
}//class
?>

Answer 1

A callback function accepts two parameters: ($postdata, $param).
$param receives whatever you define as the rule's parameter via [...] after the rule's name:
'rules' => 'required|trim|valid_email|xss_clean|check_email_existence[table,field]'
function check_email_existence($email, $param) {
// extract table and field from $param
...