phpnuxbill/system/controllers/autoload_user.php

<?php
/**
 *  PHP Mikrotik Billing (https://github.com/hotspotbilling/phpnuxbill/)
 *  by https://t.me/ibnux
 **/

/**
 * used for ajax
 **/

_auth();

$action = $routes['1'];
$user = User::_info();

switch ($action) {
    case 'isLogin':
        $bill = ORM::for_table('tbl_user_recharges')->where('id', $routes['2'])->where('username', $user['username'])->findOne();
        if ($bill['type'] == 'Hotspot' && $bill['status'] == 'on') {
            $dvc = Package::getDevice($d);
            if (file_exists($dvc) && $_app_stage != 'demo') {
                require_once $dvc;
                if ((new $d['device'])->online_customer($user, $bill['routers'])) {
                    die('<a href="' . U . 'home&mikrotik=logout&id='.$bill['id'].'" onclick="return confirm(\''.Lang::T('Disconnect Internet?').'\')" class="btn btn-success btn-xs btn-block">'.Lang::T('You are Online, Logout?').'</a>');
                } else {
                    if (!empty($_SESSION['nux-mac']) && !empty($_SESSION['nux-ip'])) {
                        die('<a href="' . U . 'home&mikrotik=login&id='.$bill['id'].'" onclick="return confirm(\''.Lang::T('Connect to Internet?').'\')" class="btn btn-danger btn-xs btn-block">'.Lang::T('Not Online, Login now?').'</a>');
                    }else{
                        die(Lang::T('Your account not connected to internet'));
                    }
                }

            } else {
                new Exception(Lang::T("Devices Not Found"));
            }
        } else {
            die('--');
        }
        break;
    default:
        $ui->display('404.tpl');
}