opencart creating and using a custom helper

Question

I created a helper in opencart following information I found here on stackoverflow, but I have a problem:

First I created a helper file called general.php and placed inside the folder:

system/helper/general.php

Then started in startup.php file

require_once(DIR_SYSTEM 'helper/general.php');

Finally, I use it inside the controller: register.php which is inside the folder catalog/controller/account/register.php.

I used it in this way:

if (empty($this->request->post['doc']) && $this->general->validate($this->request->post['doc'])) {
    $this->error['doc'] = 'doc is invalid';
}

And is returning the following error:

Fatal error: Call to a member function validate() on a non-object in / home/centralshopdistribuidora/www/vqmod/vqcache/vq2-catalog_controller_account_register.php on line 515

line 515:

if (empty($this->request->post['doc']) && $this->general->validate($this->request->post['doc'])) {

The general.php file:

function validate($doc) {
    $d1 = 0;
    $d2 = 0;
    $doc = preg_replace("/[^0-9]/", "", $doc);
    $ignore_list = array(
        '00000000000',
        '01234567890',
        '11111111111',
        '22222222222',
        '33333333333',
        '44444444444',
        '55555555555',
        '66666666666',
        '77777777777',
        '88888888888',
        '99999999999'
    );
    if (strlen($doc) != 11 || in_array($doc, $ignore_list)) {
        return false;
    } else {
        for ($i = 0; $i < 9; $i++) {
            $d1 += $doc[$i] * (10 - $i);
        }
        $r1 = $d1 % 11;
        $d1 = ($r1 > 1) ? (11 - $r1) : 0;
        for ($i = 0; $i < 9; $i++) {
            $d2 += $doc[$i] * (11 - $i);
        }
        $r2 = ($d2 + ($d1 * 2)) % 11;
        $d2 = ($r2 > 1) ? (11 - $r2) : 0;
        return (substr($doc, -2) == $d1 . $d2) ? true : false;
    }
}

Answer 1

You first need to register this helper into the registry, e.g. in Your index.php find line

// Encryption
$registry->set('encryption', new Encryption($config->get('config_encryption')));

(referring to OC 1.5.5 and higher) and after this register Your helper the same way, e.g.

// General
$registry->set('general', new General()));

This should be enough. Make sure to change the constructor call if You have some dependencies...