Request does not reach controller after a few requests

Question

I have a custom module for an online shop. Module's controller gets a product id which is sent by the user through a query string and puts it into the session. That is crucial for the shopping cart functionality.

Things are that, after clearing the cache, everything is ok, but after a few minutes/requests, the requests stop entering the controller. It seems like the response has been cached, even if:

• I have disabled the caches at admin/config/development/performance,
• I return '#cache' => ['max-age => 0] within the render array returned by the controller and
• all responses come with the header "x-drupal-cache-max-age: 0 (Uncacheable)".

I also noticed that these errors usually come with the following apache error:

AH01070: Error parsing script headers

Answer 1

If you want to disable the caching of a controller, use this method in your controller class:

  /**
   * @return int
   */
  public function getCacheMaxAge(): int {
    return 0;
  }