Codeigniter 3.1.9 MY_Form_validation is not working - codeigniter

Question

Im working on Codeigniter 3.1.9 and completed my form on local machine. i just uploaded my app some moment ago on server and getting error
Unable to access an error message corresponding to your field name
URL.(valid_url_format)
i google alot but unable to fix problem.
Filename: My_Form_validation.php
Location: application\libraries
class MY_Form_validation extends CI_Form_validation{
public function __construct()
{
parent::__construct();
}
function valid_url_format($str){
$pattern = "/^(http|https|ftp):\/\/([A-Z0-9][A-Z0-9_-]*(?:\.[A-Z0-9][A-Z0-9_-]*)+):?(\d+)?\/?/i";
if (!preg_match($pattern, $str)){
$this->set_message('valid_url_format', 'The URL you entered is not correctly formatted.');
return FALSE;
}
return TRUE;
}
function url_exists($url){
$url_data = parse_url($url); // scheme, host, port, path, query
if(!fsockopen($url_data['host'], isset($url_data['port']) ? $url_data['port'] : 80)){
$this->set_message('url_exists', 'The URL you entered is not accessible.');
return FALSE;
}
return TRUE;
}
}
Filename: UrlChecker.php
Location:application\controllers
class UrlChecker extends CI_Controller {
public function __construct() {
parent::__construct();
}
public function _initializing(){
}
public function index()
{
$this->form_validation->set_rules('link', 'URL', 'required|trim|valid_url_format|url_exists');
if ($this->form_validation->run() == FALSE)
{
echo validation_errors('<div class="alert alert-danger" role="alert">', '</div>');
}
else
{
echo 'ok';
}
}
Please check and let me know whats wrong is there hosting version problem or there is something else.

Answer 1

I always use custom validation on the fly and its the first time to try to make a custom library for additional validations, anyways i created and tested it to make sure it works, you got to make sure you follow the naming convention, the file name should be like this: MY_Form_validation.php and save it in your application/libraries then create your class:
class MY_Form_validation extends CI_Form_validation
{
// your rules
}
then you have to create error messages for every method, create a lang file in your application/language/english/form_validation_lang.php and add your custom error messages like this:
$lang['valid_url_format'] = 'The {field} field may only contain valid url.';
$lang['url_exists'] = 'The {field} field already exists';