Limit cart contents to max $1million (for ZC v1.3.9h)

class.limitCartValue.php

<?php
/**
 * This file should be uploaded as: /includes/classes/observers/class.limitCartValue.php
 * It also requires that the config.limitCartValue.php file also be installed.  See below.
 * Limit shopping cart total value, to mitigate against DDOS attacks
 */
class limitCartValue extends base {

 /**  constructor method
  * Attach listeneners to events
  */
  function __construct() {
    $_SESSION['cart']->attach($this, array('NOTIFIER_CART_ADD_CART_START', 'NOTIFIER_CART_ADD_CART_END', 'NOTIFIER_CART_UPDATE_QUANTITY_START', 'NOTIFIER_CART_UPDATE_QUANTITY_END'));
  }

 /**
   * Called by observed class when any of the notifiable events occur
   *
   * @param object $class
   * @param string $eventID
   */
  function update(&$class, $eventID, $params) {
    if ($class->total > 1000000) zen_redirect(zen_href_link(FILENAME_TIME_OUT));
  }
}

config.limitCartValue.php

<?php
/**
 * This file must be uploaded to /includes/auto_loaders/config.limitCartValue.php
 */

$autoLoadConfig[10][] = array('autoType'=>'class',
                              'loadFile'=>'observers/class.limitCartValue.php');
$autoLoadConfig[135][] = array('autoType'=>'classInstantiate',
                              'className'=>'limitCartValue',
                              'objectName'=>'limitCartValue');