HackThisSite Remote Mission API

<?php
/**
Copyright (c) 2012, HackThisSite.org
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
    * Neither the name of the HackThisSite.org nor the
      names of its contributors may be used to endorse or promote products
      derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/**
* Authors:
*   Bren2010 ( Brendan Mc. )
**/

class HTSMission {

        // Edit these -- they will be assigned to you.
        var $serverId = 0;
        var $missionId = 0;

        // Do not edit these
        var $remoteUrl = 'hackthissite.org';
        var $remotePort = '51064';
        var $userId;

        // Initiates class.  You should call this on every page load, but
        // it is fine if you only call it on the index page and the
        // winning page of the mission.
        public function __construct() {
                if (!isset($_SESSION)) session_start();
                if (!empty($_SESSION['userId'])) $this->userId = $_SESSION['userId'];
                if (!empty($_GET['userId'])) {
                        $_SESSION['userId'] = (int) $_GET['userId'];
                        header('Location: ' . $_SERVER['PHP_SELF']);
                        die;
                } else if (empty($_SESSION['userId']) && empty($_GET['userId'])) {
                        die('Access denied.');
                }
        }

        // Call to mark mission as completed.
        public function finish() {
                $socket = @fsockopen($this->remoteUrl, $this->remotePort, $errno, $errstr, 1);
                if (!$socket) die('Unable to connect to HackThisSite\'s servers!
                        Please contact a HackThisSite developer.');

                $info = stream_get_meta_data($socket);
                if ($info['timed_out']) die('Coult not contact HTS.');

                $serverId = $this->uncompliment($this->serverId);
                $userId = $this->uncompliment($this->userId);
                $missionId = $this->uncompliment($this->missionId);

                $toWrite = '';

                foreach($serverId as $byte) { $toWrite .= chr($byte); }
                foreach ($userId as $byte) { $toWrite .= chr($byte); }
                foreach ($missionId as $byte) { $toWrite .= chr($byte); }

                fwrite($socket, $toWrite);
                fclose($socket);
        }


        private function uncompliment($integer) {
                $toReturn = array();

                while (true) {
                                array_push($toReturn, $integer % 256);
                                $integer = floor($integer / 256);

                                if ($integer == 0) break;
                }

                return array_reverse(array_pad($toReturn, 4, 0));
        }

}