public static function getInstance()
 {
     if (is_null(self::$instance)) {
         self::$instance = new self();
     }
     return self::$instance;
 }
 public function get_api()
 {
     if (!$this->api) {
         require_once trailingslashit(dirname(_DTBAKER_SUPPORT_HUB_CORE_FILE_)) . 'extensions/envato/class.envato-api.php';
         $this->api = envato_api_basic::getInstance();
         $this->api->set_personal_token($this->get('envato_token'));
         $this->api->set_client_id($this->get('envato_app_id'));
         $this->api->set_client_secret($this->get('envato_app_secret'));
         $this->api->set_redirect_url($this->generate_oauth_redirect_url());
         $this->api->set_cookie($this->get('envato_cookie'));
     }
     return $this->api;
 }
<?php

if (!file_exists('config.php')) {
    die('Copy the config.sample.php to config.php');
}
require 'config.php';
if (defined('REDIRECT_URL')) {
    $redirect_uri = REDIRECT_URL;
} else {
    //try to guess the redirect urL
    $redirect_uri = (isset($_SERVER['HTTPS']) ? 'https' : 'http') . "://" . $_SERVER['HTTP_HOST'] . dirname($_SERVER['SCRIPT_NAME']) . '/';
}
//load the API (thanks Dave!)
require 'envato-api.class.php';
$api = new envato_api_basic();
$api->set_client_id(CLIENT_ID);
$api->set_client_secret(SECRET_APP_KEY);
$api->set_redirect_url($redirect_uri);
//list items
if (isset($_GET['items'])) {
    $return = array();
    foreach ($_GET['items'] as $slug => $item_id) {
        if (isset($items[$item_id])) {
            $return[] = $items[$item_id];
        }
    }
    @header('Content-type: application/json');
    echo json_encode($return);
    exit;
    //redirect to Envato authorization page
} elseif (isset($_GET['auth'])) {