private function canModifyFrontendSession(Request $request, array $referer = null)
{
return null !== $referer && !$request->query->has('pdf') && !$request->query->has('file') && !$request->query->has('id') && isset($referer['current']) && 'contao_frontend' === $request->attributes->get('_route') && $this->getRelativeRequestUri($request) !== $referer['current'] && !$request->isXmlHttpRequest();
}