[PHP] Header Finder

<?php
# upload to /var/www/html
# made by drought and jester, dont be a meme plz
    $apiKey = "DR0UGH7";

    if(empty($_GET['key'])){
        die('API Key cannot be empty!');
    }else{
        if(isset($_GET['key'])){
            if(empty($_GET['rIP']) || empty($_GET['rPort'])){
                die('Remote IP and/or Remote Port fields cannot be empty!');
            }else{
                if($_GET['key'] == $apiKey)
                {
                    if(isset($_GET['rIP']) && isset($_GET['rPort'])){
                        $rIP  = $_GET['rIP'];
                        $rPort = $_GET['rPort'];

                        if (filter_var($rIP, FILTER_VALIDATE_IP)) {
                            if(is_numeric($rPort)){
                                $url = "http://".$rIP.":".$rPort."/";

                                $ch = curl_init($url);
                                curl_setopt($ch, CURLOPT_HEADER, 1);
                                curl_setopt($ch, CURLOPT_NOBODY, 1);
                                curl_setopt($ch, CURLOPT_TIMEOUT, 10);
                                $ch = curl_exec($ch);
                            }else{
                                die("$rPort is not numeric!");
                            }

                        } else {
                            die("$rIP is not a valid IP!");
                        }
                    }else{
                        die('Remote IP and/or Remote Port fields cannot be empty!');
                    }
                }else{
                    die('Wrong API Key!');
                }
            }
        }else{
            die('API Key not set!');
        }
    }
?>