Creating a custom codeigniter validation rule - php

Question

I have a function in my login form that checks if the email and password match the values in the database and if so it logs the user into the system.
I would like to display a validation error if this function returns false.
My problem is that I am unsure how to go about creating this. The message relates to both the password and email fields so I would not want a rule for each input field just display a single message.
I have tried using flashdata to achieve this but it only works when the page has been refreshed.
How can I created a new validation rule solely for the function $this->members_model->validate_member() ??
$this->form_validation->set_error_delimiters('<div class="error">', '</div>');
$this->form_validation->set_rules('email_address', '"Email address"', 'trim|required|valid_email');
$this->form_validation->set_rules('password', '"Password"', 'trim|required');
if ($this->form_validation->run() == FALSE)
{
$viewdata['main_content'] = 'members/login';
$this->load->view('includes/template', $viewdata);
}
else
{
if($this->members_model->validate_member())
{

Answer 1

You use the callback_ in your rules, see callbacks, for ex.
$this->form_validation->set_rules('email_address', '"Email address"', 'trim|required|valid_email|callback_validate_member');
and add the method in the controller. This method needs to return either TRUE or FALSE
function validate_member($str)
{
$field_value = $str; //this is redundant, but it's to show you how
//the content of the fields gets automatically passed to the method
if($this->members_model->validate_member($field_value))
{
return TRUE;
}
else
{
return FALSE;
}
}
You then need to create a corresponding error in case the validation fails
$this->form_validation->set_message('validate_member','Member is not valid!');

Answer 2

One best way to achieve this is extending CodeIgniter’s Form Validation library. Let say we want to create a custom validator named access_code_unique for the field access_code of the database table users.
All you have to do is creating a Class file named MY_Form_validation.php in application/libraries directory. The method should always return TRUE OR FALSE
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
class MY_Form_validation extends CI_Form_validation {
protected $CI;
public function __construct() {
parent::__construct();
// reference to the CodeIgniter super object
$this->CI =& get_instance();
}
public function access_code_unique($access_code, $table_name) {
$this->CI->form_validation->set_message('access_code_unique', $this->CI->lang->line('access_code_invalid'));
$where = array (
'access_code' => $access_code
);
$query = $this->CI->db->limit(1)->get_where($table_name, $where);
return $query->num_rows() === 0;
}
}
Now you can easily add your new created rule
$this->form_validation->set_rules('access_code', $this->lang->line('access_code'), 'trim|xss_clean|access_code_unique[users]');