public function postEntry(array $data, Form $form)
 {
     if (!empty($data['Website'])) {
         if (!filter_var($data['Website'], FILTER_VALIDATE_URL)) {
             $form->addErrorMessage('Website', _t('GuestbookController.INVALIDWEBSITEFORMAT', "Invalid format for website."), 'bad');
             return $this->redirectBack();
         }
     }
     if (Session::get("GuestbookPosted") > time() - $this->FloodLimit) {
         $floodMessage = _t('GuestbookController.FLOODLIMITEXCEEDED', "You have already posted the last {seconds} seconds. Please wait.", "", $this->FloodLimit);
         $form->sessionMessage($floodMessage, 'bad');
         return $this->redirectBack();
     }
     $entry = GuestbookEntry::create();
     $entry->GuestbookID = $this->ID;
     $form->saveInto($entry);
     $entry->write();
     $form->sessionMessage(_t('GuestbookController.ENTRYSAVED', "Entry has been saved."), 'good');
     Session::set('GuestbookPosted', time());
     return $this->redirectBack();
 }