code: public function put($key = null, $filter = true)
      {
          parse_str(file_get_contents("php://input"), $_PUT);
  
          if ($key == null) {
              return $_PUT;
          }
  
          return $this->filter($_PUT[$key], $filter);
      }
docs: HTTP PUT Request
  
  @param string $key
  @param bool   $filter
  
  @return string|null