knp_snappy_1.php

class DownloadSpecificationsController extends Controller {
    /**
    * @Route("/generate-pdf", name="app_generate_pdf")
    */
    public function downloadSpecifications() {
        $html = $this->renderView('download-specifications/pdf.html.twig');
        $filename = sprintf('specifications-%s.pdf', date('Y-m-d-hh-ss'));
        return new Response(
            $this->get('knp_snappy.pdf')->getOutputFromHtml($html),
            200,
            [
            'Content-Type' => 'application/pdf',
            'Content-Disposition' => sprintf('attachment; filename="%s"', $filename),
            ]
        );
    }
}