php – Creating a custom codeigniter validation rule-ThrowExceptions

Exception or error:

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);
How to solve:

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

     return TRUE;
     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!');


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() {
            // 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]'); 

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