rendering PDF from Twig

/**
 * Generate and save a PDF
 *
 * @Route("/contracts/{id}/pdf", name="contract_pdf")
*/
public function pdfAction($id, Request $request) {
    // get contract from database
    $em = $this->getDoctrine()->getManager();
    $c = $em->getRepository('AppBundle:Contract')->find($id);

    $path = $request->server->get('DOCUMENT_ROOT');    // C:/wamp64/www/
    $path = rtrim($path, "/");                         // C:/wamp64/www

    $html = $this->renderView('contracts/pdf/content.html.twig', array('c' => $c));

    $header = $this->renderView('contracts/pdf/header.html.twig', array(
        'path' => $path
    ));
    $footer = $this->renderView('contracts/pdf/footer.html.twig', array(
        'customer' => $c->getCustomer()
    ));

    $output = $path . $request->server->get('BASE');        // C:/wamp64/www/project/web
    $output .= '/pdf/contract-'. $c->getCustomerCode() .'.pdf';

    // Generate PDF file
    $this->get('knp_snappy.pdf')->generateFromHtml($html, $output, array(
        'header-html' => $header,
        'footer-html' => $footer,
    ));

    // Message + redirection
    $this->addFlash('success', 'The PDF file has been saved.');
    return $this->redirectToRoute('contract');
}