public function executeSearchRequest(sfWebRequest $request)
 {
     if (LinkParser::FilterByPeriod($request)) {
         $errors = LinkParser::ValidateSearchRequest($request, true);
         $this->by_period = true;
         $this->DoSearch($errors, $request, true);
     } else {
         $errors = LinkParser::ValidateSearchRequest($request);
         $this->DoSearch($errors, $request);
     }
 }