I have a custom module providing a HTML5 Service Worker file under /modules/custom/my_blocks/assets/js/service-worker.js. Since the Service Worker is not located in the root of the Drupal server, I need to return the file with an additional Service-Worker-Allowed HTTP header.

How to do that within my module?

  • This isn't a Drupal issue. The file is a static file, it is not processed through Drupal, so HTTP headers need to be added through the server.
    – Jaypan
    Commented Sep 8, 2021 at 20:29
  • But I could provide the static file dynamically via Drupal, right? Hence it should also interceptable.
    – david
    Commented Sep 8, 2021 at 21:06
  • Ahh I get it, Remi provided the answer for how to serve it through Drupal. That said, I would look at how to do this with .htaccess or whatever, so that Drupal doesn't have to be bootstrapped to serve the file.
    – Jaypan
    Commented Sep 9, 2021 at 5:54
  • .htaccess wouldn't work. I need to create the service worker an/or related cache files dynamically, as they need to be updated as the contents of my Drupal site change.
    – david
    Commented Sep 9, 2021 at 10:53

1 Answer 1


To provide a dynamic file, you need to make a Controller with a method like:

 public function serve(Request $request) {
    $file_str = $file_system->realpath($module_handler->getModule('my_module')->getPath()) . '/assets/js/service-worker.js';

    if (file_exists($file_str)) {

      $response = new BinaryFileResponse($file_str, 200);
      $response->headers->set('Content-Type', 'application/javascript');
      // Allow same origin service worker.
      $response->headers->set('Service-Worker-Allowed', '/');

      return $response;

    throw new NotFoundHttpException();

And then define a route for it, where the path is not existing as a static file, like:

  path: '/serviceworker' 
    _controller: '\Drupal\my_module\Controller\ExampleController::serve' 
    _permission: 'access content' 

see - https://www.drupal.org/docs/drupal-apis/routing-system/introductory-drupal-8-routes-and-controllers-example.

  • Excellent clear and clean solution. That's what i was looking for. Lotta thx!
    – david
    Commented Sep 9, 2021 at 8:58
  • 1
    Fixed some small issue: Drupal doesn't intercept the "serviceworker.js" route, so I had to remove the extension. The "/serviceworker" route on the other hand works as expected.
    – david
    Commented Sep 9, 2021 at 10:40
  • 1
    np ;) and thank you for the code fixes ;) Could you then also mark the answer as accepted pls ?
    – rémy
    Commented Sep 9, 2021 at 11:17

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