/**
  * Reject a pending event by DELETEing to /events/{id}/approval
  *
  * @param Request $request
  * @param PDO $db
  *
  * @return void
  */
 public function rejectAction($request, $db)
 {
     if (!isset($request->user_id)) {
         throw new Exception("You must be logged in to create data", 400);
     }
     $event_id = $this->getItemId($request);
     $event_mapper = new EventMapper($db, $request);
     if (!$event_mapper->thisUserCanApproveEvents()) {
         throw new Exception("You are not allowed to reject this event", 403);
     }
     $result = $event_mapper->reject($event_id, $request->user_id);
     if (!$result) {
         throw new Exception("This event cannot be rejected", 400);
     }
     header("Content-Length: 0", null, 204);
     return;
 }