I’m working with Cellular Detect module and from what I perceive, we have to manually add Drupal Developer cache context mobile_detect_is_mobile so as to have Drupal Developer web page cached in a different way based mostly on Drupal Developer person gadget kind. I used to be in a position to make it work by making use of Drupal Developer cache context utilizing a preprocess on my paragraph like so :

perform hook_preprocess_paragraph(&$variables){     $variables['#cache']['contexts'][] = 'mobile_detect_is_mobile'; } 

Though, I do not like Drupal Developer thought of including Drupal Developer context at Drupal Developer preprocess stage and I used to be trying to have a extra world resolution through the use of an EventSubscriber that checks Drupal Developer path and apply Drupal Developer cache context for particular paths. It looks like Drupal Developer cache context just isn’t taken in consideration. Right here my EventSubscriber :

class MobileDetectSubscriber implements EventSubscriberInterface {      /**      * @var SymfonyComponentHttpFoundationRequest      */     protected $request;      /**      * @param SymfonyComponentHttpFoundationRequestStack $request_stack      */     public perform __construct(RequestStack $request_stack) {     $this->request = $request_stack->getCurrentRequest();;     }      /**      * @param SymfonyComponentHttpKernelEventFilterResponseEvent $occasion      *   Drupal Development Company occasion to course of.      */     public perform onRespond(FilterResponseEvent $occasion) {         if (!$occasion             ->isMasterRequest()) {             return;         }         $response = $occasion             ->getResponse();         if (!$response instanceof CacheableResponseInterface) {             return;         }          if($this->request->getRequestUri() == "/"){              $mobile_detect = new CacheableMetadata();             $mobile_detect->setCacheContexts(['mobile_detect_is_mobile']);             $response->addCacheableDependency($mobile_detect);         }     }      /**      * @return array      *   An array of occasion listener definitions.      */     public static perform getSubscribedEvents() {         // Precedence 5, in order that it runs earlier than FinishResponseSubscriber, however after         // occasion subscribers that add Drupal Developer related cacheability metadata (which         // have precedence 10). This one is conditional, so should run after these.         $occasions[KernelEvents::RESPONSE][] = ['onRespond', 5];         return $occasions;     } } 

What am I lacking ?