/**
  * Get redirect URI from FlexForm or TypoScript
  *
  * @return string|null
  */
 public function getRedirectUri()
 {
     $uri = null;
     $target = $this->getTarget();
     if ($target !== null) {
         $this->uriBuilder->setTargetPageUid($target);
         $uri = $this->uriBuilder->build();
     }
     return $uri;
 }