Server side Visual Composer update script

vc_update.php

<?php
/**
 * Visual Composer Extended License Updater
 * Server Side Update Script
 * Author: dtbaker
 * Details: http://dtbaker.net/web-development/visual-composer-plugin-updates-in-3rd-party-themes/
 *
 * Upload this script to your website (e.g. yourwebsite.com/vc_update.php)
 * Adjust the API key to your own
 * Add the other code into your WordPress theme
 * Enjoy
 *
 */


define('_VC_API_PERSONAL_TOKEN',  'dfasdfasdfasdfasdfasdf'); // ****** CHANGE ME ******* put YOUR OWN personal token from build.envato.com here
define('_VC_EXTENDED_LICENSE_CODE',  '12345334-2594-4228-8c61-77773333333'); // ****** CHANGE ME ******* put YOUR OWN Visual Composer extended license code here

$json_result = array();

// we get the purchase code from the users theme purchase.
// this lets us validate we have a legit theme buyer before we go and give them the latest version of visual composer
$purchase_code = isset($_GET['purchase']) ? $_GET['purchase'] : '';
$purchase_code = strtolower(preg_replace('#([a-z0-9]{8})-?([a-z0-9]{4})-?([a-z0-9]{4})-?([a-z0-9]{4})-?([a-z0-9]{12})#','$1-$2-$3-$4-$5',$purchase_code));
if(strlen($purchase_code)==36){

    // we have a correctly formatted purchase code! ask the API if it's legit
    // should really cache results but this URL will only be hit occasionally

    $result = basic_envato_api( 'v2/market/author/sale?code='.$purchase_code );
    if($result && !empty($result['item']['id'])){
        // we have a verified purchase! yay!
        // now we make sure that particular item is allowed to receive free updates to visual composer
        switch($result['item']['id']){
            case '123455': // ****** CHANGE ME ******* Put your Visual Composer enabled Envato item ids in here.
            case '123456': // ****** CHANGE ME ******* Put your Visual Composer enabled Envato item ids in here.
            case '123457': // ****** CHANGE ME ******* Put your Visual Composer enabled Envato item ids in here.
                $vc_update_allowed = true;
                break;
            default:
                // the user hasn't purchased one of our visual composer compatible themes, so don't give it to them!
                $vc_update_allowed = false;

        }
        if($vc_update_allowed){
            // all good, we can go and send the latest version of visual composer to this buyer
            // we get the latest download URL from Envato API and pass that back to the theme PHP code which will handle the download.
            $download_result = basic_envato_api('v1/market/private/user/download-purchase:'._VC_EXTENDED_LICENSE_CODE.'.json');
            if($download_result && !empty($download_result['download-purchase']['wordpress_plugin'])){
                $json_result['download_url'] = $download_result['download-purchase']['wordpress_plugin'];
            }
        }
    }

}

// send our data back to the theme PHP script for download handling.
header("Content-type: text/javascript");
echo json_encode($json_result);


function basic_envato_api($endpoint){
    $ch = curl_init('https://api.envato.com/'.$endpoint);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        'Authorization: Bearer '. _VC_API_PERSONAL_TOKEN
    ));
    curl_setopt($ch, CURLOPT_USERAGENT, 'dtbaker Visual Composer Update');
    $response = curl_exec($ch);
    return json_decode($response,true);
}