code: public function getParam(
          string $name,
          int $filter = \FILTER_DEFAULT,
          $options = null
      ) {
          // Can be useful when INPUT_REQUEST is implemented for the filter_input()
          // function.
          //return filter_input(\INPUT_REQUEST, $name, $filter, $options);
          return isset($_REQUEST[$name]) ? filter_var($_REQUEST[$name], $filter, $options)
              : null;
      }
docs: The method returns the parameter value of request by the passed key. It's
  wrapper over the filter_var() function.
  @param string $name Name of a variable to get.
  @param int $filter
  @param mixed $options Associative array of options or bitwise disjunction
  of flags. If filter accepts options, flags can be provided in "flags"
  field of array.
  @return mixed Value of the requested variable on success, false if the filter
  fails, or null if the variable is not set.