code: public function putAction()
      {
          if (!preg_match('/\/page\/(\w+[\-\w]*)\/text\/(..)\/(\w+)$/', $this->name, $matches)) {
              throw new InvalidParameterException("Invalid parameters");
          }
          list($dummy, $pageName, $language, $oldName) = $matches;
  
          $request = $this->environment->getRequestHelper();
          $newName = $request->getIdentifierParam('name');
          $content = $request->getParam('content', '');
  
          try {
              $pageTexts = $this->getTextModel($pageName);
              $text = $pageTexts->modifyTextContainer($oldName, $newName, $this->filter($content), $language);
              $this->environment->sendJSONResult($text);
          } catch (\Exception $e) {
              throw new InvalidParameterException($e->getMessage());
          }
      }
docs: Changes an existing text container.
  
  @throws \justso\justapi\InvalidParameterException