/**
  * Listens to the routing.load_configuration event.
  *
  * @param sfEvent An sfEvent instance
  */
 public static function listenToApplicationThrowExceptionEvent(sfEvent $event)
 {
     $apiKey = sfConfig::get('app_sf_hoptoad_notifier_plugin_api_key', false);
     if ($apiKey) {
         if (!defined('HOPTOAD_API_KEY')) {
             define('HOPTOAD_API_KEY', $apiKey);
         }
         $r = $event->getSubject();
         Hoptoad::exceptionHandler($r);
     }
 }
<?php

require_once 'Hoptoad.php';
Hoptoad::installHandlers("YOUR_HOPTOAD_API_KEY");
 /**
  * Handle a raised exception
  *
  * @param string $exception
  * @return void
  * @author Rich Cavanaugh
  */
 public static function exceptionHandler($exception)
 {
     $trace = Hoptoad::tracer($exception->getTrace());
     Hoptoad::notifyHoptoad(HOPTOAD_API_KEY, $exception->getMessage(), $exception->getFile(), $exception->getLine(), $trace, null);
 }