/** * Returns the number of seconds after the time specified in the response's Date * header when the response should no longer be considered fresh. * * First, it checks for a s-maxage directive, then a max-age directive, and then it falls * back on an expires header. It returns null when no maximum age can be established. * * @return int|null Number of seconds * * @api */ public function getMaxAge() { return parent::getMaxAge(); }