Service worker context closed

Author: H | 2025-04-24

Closed daniel-nagy opened this issue 10 comments Closed in the service worker context. Otherwise if the service worker updates it will not set needRefresh. Closed brainkim opened this issue 20 comments Closed Your service workers are throwing errors in safari. 5434. Additional context. Service workers

Service Worker context closed (WebKitInternal:0)

/ "frontend/build" / "sw.js" response = HttpResponse(open(sw_path).read(), content_type='application/javascript') return responseThe logic is very simple, we read the content of the frontend/build/sw.js and return it back.Update django_pwa_app/urls.pyfrom django.contrib import adminfrom django.urls import pathfrom django.views.generic import TemplateViewimport django_pwa_app.viewsurlpatterns = [ path('', TemplateView.as_view(template_name="index.html")), path('sw.js', django_pwa_app.views.service_worker), # new path('admin/', admin.site.urls),]Let's run django server and do a test(env)$ python manage.py runserver# check on Service WorkerUpdate frontend/src/application/app.jsimport "../styles/index.scss";import "bootstrap/dist/js/bootstrap.bundle";if ('serviceWorker' in navigator) { window.addEventListener('load', () => { navigator.serviceWorker.register('/sw.js').then(registration => { console.log('SW registration succeeded:', registration); navigator.serviceWorker.ready .then(function (registration) { console.log('SW is active:', registration.active); }); }).catch(registrationError => { console.log('SW registration failed: ', registrationError); }); });}'serviceWorker' in navigator is to check if the browser supports service workernavigator.serviceWorker.register is to register the service workernavigator.serviceWorker.ready is to make sure the service worker is active now.First LoadNow, let's visit for the first time.If we open the devtools, we will see some messages in the console.sw.js:7 service worker installapp.js:7 SW registration succeeded: ServiceWorkerRegistration {installing: ServiceWorker, waiting: null, active: null, navigationPreload: NavigationPreloadManager, scope: " …}sw.js:10 service worker activateapp.js:9 SW is active: ServiceWorker {scriptURL: " state: "activating", onstatechange: null, onerror: null}activate event is fired after the install event.Second LoadNow let's refresh the page and check the console again.sw.js:13 fetch fetch fetch fetch SW registration succeeded: ServiceWorkerRegistration {installing: null, waiting: null, active: ServiceWorker, navigationPreload: NavigationPreloadManager, scope: " …}sw.js:13 fetch SW is active: ServiceWorker {scriptURL: " state: "activated", onstatechange: null, onerror: null}sw.js:13 fetch fetch event fires every time any resource controlled by a service worker is fetched, which includes the documents inside the scopeThe install and activate event are not fired this time because the service worker is already runningUpdate Service WorkerPlease open chrome devtools, go to Application tab and click the Service Worker on the left sidebar.We can see the service worker is active and running.And we can click the top right link to Update or Unregister the service worker.There will be a point in time where your service worker will need updating. When that time comes, you'll need to follow these steps:Update your service worker JavaScript file. When the user navigates to your site, the browser tries to redownload the script file that defined the service worker in the background. If there is even a byte's difference in the service worker file compared to what it currently has, it considers it new.Your new service worker will be started and the install event will be fired.At this point the old service worker is still controlling the current pages so the new service worker will enter a waiting state.When the currently open pages of your site are closed, the old service worker will be killed and the new service worker will take control.Once your new service worker takes control, its activate event will be fired.You can check Update a service worker to learn more.During the development, we can click the Update on realod checkbox, this can force the browser always install the latest service workerNotes:Service worker can only work on localhost or HTTPS.If you want to test HTTPS on local env, please check ngrokIt is not recommended To add this feature, but that is an ongoing conversation. Testing Service Worker SuspensionWe've tried several approaches to triggering service worker suspension during tests: Approach Issues with the approach Wait an arbitrary amount of time (for example 30 seconds) This makes testing slow and unreliable, especially when running multiple tests. It does not work when using WebDriver, since WebDriver uses Chrome's DevTools API, and the service worker is not suspended when DevTools is open. Even if we could bypass it, we would still have to check if the service worker was suspended and we don't have a way to do that. Run an infinite loop in the service worker According to the spec, this can lead to termination depending on how the browser implements this functionality. Chrome does not terminate the service worker in this case so we cannot test the scenario when the service worker gets suspended. Having a message in the service worker to check if it's been suspended Sending a message wakes up the service worker. This can be used to check if the service worker was asleep, but it breaks results for tests that need to do checks immediately after suspending the service worker. Kill the service worker process using chrome.processes.terminate() The service worker for the extension shares a process with other parts of the extension, so killing this process using chrome.process.terminate() or Chrome's process manager GUI kills not only the service worker but also any extension pages. We ended up with a test that checks

[Bug]: Closing browser contexts can leave dangling service workers

Worker was registered on this origin,there's still a message saying there is no current service worker.That's because this page is not within the registered service worker's scope.Scope limits what pages the service worker controls.In this example, that means the service worker loaded from /subdir/sw.js can only control pages located in /subdir/ or its subtree.The above is how scoping works by default,but the maximum allowed scope can be overridden by setting theService-Worker-Allowed response header,as well as passing ascope option to the register method.Unless there's a very good reason to limit service worker scope to a subset of an origin,load a service worker from the root directory of the web server so that its scope is as broad as possible,and don't worry about the Service-Worker-Allowed header. It's a lot simpler for everyone that way.ClientWhen it's said that a service worker is controlling a page, it's really controlling a client.A client is any open page whose URL falls within the scope of that service worker.Specifically, these are instances of a WindowClient.The lifecycle of a new service workerIn order for a service worker to control a page,it must first be brought into existence, so to speak.Let's begin with what happens when a brand new service worker is deployed for a website with no active service worker.RegistrationRegistration is the initial step of the service worker lifecycle: // Don't register the service worker // until the page has fully loaded window.addEventListener('load', () => { // Is service worker available? if ('serviceWorker' in navigator) { navigator.serviceWorker.register('/sw.js').then(() =>. Closed daniel-nagy opened this issue 10 comments Closed in the service worker context. Otherwise if the service worker updates it will not set needRefresh.

Injectable Service Worker context cache services

It's hard to know what service workers are doing without understanding their lifecycle.Their inner workings will seem opaque, even arbitrary.It helps to remember that—like any other browser API—service worker behaviors are well-defined,specified, and make offline applications possible,while also facilitating updates without disrupting the user experience.Before diving into Workbox,it's important to understand the service worker lifecycle so that what Workbox does makes sense.Defining termsBefore getting into the service worker lifecycle,it's worth defining some terms around how that lifecycle operates.Control and scopeThe idea of control is crucial to understanding how service workers operate.A page described as being controlled by a service worker is a page that allows a service worker to intercept network requests on its behalf.The service worker is present and able to do work for the page within a given scope.ScopeA service worker's scope is determined by its location on a web server.If a service worker runs on a page located at /subdir/index.html, and is located at /subdir/sw.js,the service worker's scope is /subdir/.To see the concept of scope in action, check out this example:Navigate to message will appear that says no service worker is controlling the page.However, that page registers a service worker from the page. Because the service worker has been registered and is now active,it's controlling the page.A form containing the service worker's scope,current state, and its URL will be visible.Note: having to reload the page has nothing to do with scope,but rather the service worker lifecycle, which will be explained later on.Now Navigate to though a service Django PWA Tutorial Series:IntroductionAdd Web app manifest to DjangoAdd Service Worker to DjangoFallback Offline Page in DjangoCaching and Routing (coming soon)How to add install button to PWA (coming soon)Send Web Push Notification from Django (part 1) (coming soon)Send Web Push Notification from Django (part 2) (coming soon)The source code is available on the end of this chapter, you should be able to:Understand what is Service Worker, and the life cycle.Learn to develop Service Worker with Workbox packages.Serve Service Worker in Django.Basic conceptsA service worker is a type of web worker. It's essentially a JavaScript file that runs separately from the main browser thread, intercepting network requests, caching or retrieving resources from the cache, and delivering push messages.Because workers run separately from the main thread, service workers are independent of the application they are associated with.Service worker lifecycle:A service worker goes through three steps in its lifecycle:RegistrationInstallationActivationScopeThe scope of the service worker determines which files the service worker controls, in other words, from which path the service worker will intercept requests. The default scope is the location of the service worker file, and extends to all directories below. So if service-worker.js is located in the root directory, the service worker will control requests from all files at this domain.As you know, Django developers usually put JS files under /static/js path. To resolve this issue, we should create a Django view for /sw.js and return content of /static/js/sw.js back.Vanilla jsI have seen some people and online resource teaching people to write Service worker in vanilla js.However, this is not the best way.As I said, frontend ecosystem is very great now. We can use other package to help us get things done in easier and better way.WorkboxWorkbox is a set of libraries that can power a production-ready service worker for your Progressive Web App.Let's first install workbox-webpack-plugin to our frontend project.$ cd frontend$ npm install workbox-webpack-pluginUpdate frontend/webpack/webpack.common.jsconst {InjectManifest} = require('workbox-webpack-plugin');plugins: [ ... new InjectManifest({ swSrc: './src/sw.js', }),],Notes:We add const {InjectManifest} = require('workbox-webpack-plugin'); at the top.We add InjectManifest to the plugins, and set the service worker source file path.With injectManifest, we have more control of the Service Worker and we will do more things in the next chapters.Let's create frontend/src/sw.jsconst manifest = self.__WB_MANIFEST;if (manifest) { // do nothing}self.addEventListener('install', function(event) { console.log('service worker install');});self.addEventListener('activate', function(event) { console.log('service worker activate');});self.addEventListener('fetch', event => { console.log(`fetch ${event.request.url}`);});Notes:I will talk about const manifest = self.__WB_MANIFEST; later, now we can ignore it.We added event handler to install, activate and fetch.$ cd frontend$ npm run watchWe can ignore the warning below:WARNING in InjectManifest has been called multiple times, perhaps due to running webpack in --watch mode. The precache manifest generated after the first call may be inaccurate! Please see for more information.This is the directory structurebuild├── assets│ # files omitted for brevity├── css│ # files omitted for brevity├── index.html├── js│ # files omitted for brevity├── manifest.json├── sw.js # newServe Service WorkerNext, we will use Django view to serve the frontend/build/sw.js.Create django_pwa_app/views.pyfrom django.conf import settingsfrom django.http import HttpResponsedef service_worker(request): sw_path = settings.BASE_DIR

This method is available in a service worker context

This example, that promise does two asynchronous things:Creates a new Cache instance named 'MyFancyCache_v1'.After the cache is created,an array of asset URLs are precached using its asynchronousaddAll method.Installation fails if the promise(s) passed to event.waitUntil arerejected.If this happens, the service worker is discarded.If the promises resolve,installation succeeds and the service worker's state will change to 'installed' and will then activate.ActivationIf registration and installation succeed,the service worker activates, and its state becomes 'activating'Work can be done during activation in the service worker'sactivate event.A typical task in this event is to prune old caches,but for a brand new service worker,this isn't relevant for the moment,and will be expanded on when we talk about service worker updates.For new service workers, activate fires immediately after install is successful.Once activation finishes,the service worker's state becomes 'activated'.Notice that, by default,the new service worker won't begin controlling the page until the next navigation or page refresh.Handling service worker updatesOnce the first service worker is deployed,it'll likely need to be updated later.For example, an update may be required if changes occur in request handling or precaching logic.When updates happenBrowsers will check for updates to a service worker when:The user navigates to a page within the service worker's scope.navigator.serviceWorker.register()is called with a URL different from the currently installed service worker—but don't change a service worker's URL!navigator.serviceWorker.register()is called with the same URL as the installed service worker,but with a different scope.Again, avoid this by keeping the scope at the root of an origin if possible.When events such as 'push' or

context - Api - Mock Service Worker Docs

That the first image has a stock level of around 80-90%, while the second image has a stock level of around 20-30%.By providing the additional image as a reference, the VLM now estimates the stock level of the second image at 20–30%, which is significantly more accurate. Multi-image input can also be used in more complex multimodal RAG pipelines where example images are dynamically added to the prompt based on the user’s input. Multi-image VLMs can also be used for basic video understanding by sampling a small set of frames from a video and providing it to the VLM. However, many VLMs that accept multi-image input have limited context windows (10–20 frames) and may not have been trained on video data. To truly understand video input, we recommend using a VLM trained on video-specific datasets and a long context window. Video understanding The latest VLMs have full video understanding capabilities with large context lengths, frame compression and video training data. This enables VLMs to ingest longer videos and have improved temporal understanding: the ability to understand actions and trends over time. The first example showed how to use a single frame from a livestream to detect a fire but that same method wouldn’t be able to tell you if the fire is growing or getting smaller because it lacks the temporal context. A VLM with long context and video understanding processes many frames across time to understand if the fire is growing or not. Here are some examples from the Cosmos Nemotron model families.Sequential visual understandingVLMs with sequential understanding relies on processing frames in a sequence, enabling them to capture the progression of actions and events over time. Unlike multi-image models, which process a limited number of frames without explicit temporal connections, sequential video models incorporate temporal dynamics by analyzing frames in an orderly sequence.This is helpful in situations where you want to capture the causality of events in a video, as it enables the model to track the progression of actions over time and establish cause-effect relationships. The next few examples are based on the following video where a worker drops a box in a warehouse. We discuss a few prompts and responses.Figure 5. Input warehouse video to the VLM for scene understandingPrompt: What happened in this video?VLM response:The video shows a warehouse worker in a yellow safety vest and hard hat performing various tasks. The worker is seen walking through the warehouse, carrying boxes, and interacting with the shelving units. The warehouse has green metal shelving with labels like "C", "D", "E", and "F" on the aisles.The worker appears to be in the process of organizing or retrieving items from the shelves. At one point, they're seen bending. Closed daniel-nagy opened this issue 10 comments Closed in the service worker context. Otherwise if the service worker updates it will not set needRefresh. Closed brainkim opened this issue 20 comments Closed Your service workers are throwing errors in safari. 5434. Additional context. Service workers

Developer Instance - service worker content closed

{ console.log('Service worker registered!'); }).catch((error) => { console.warn('Error registering service worker:'); console.warn(error); }); } });This code runs on the main thread and does the following:Because the user's first visit to a website occurs without a registered service worker,wait until the page is fully loaded before registering one.This avoids bandwidth contention if the service worker precaches anything.Though service worker is well-supported,a quick check helps to avoid errors in browsers where it isn't supported.When the page is fully loaded, and if service worker is supported, register /sw.js.Some key things to understand are:Service workers areonly available over HTTPS or localhost.If a service worker's contents contain syntax errors,registration fails and the service worker is discarded.Reminder: service workers operate within a scope.Here, the scope is the entire origin, as it was loaded from the root directory.When registration begins, the service worker state is set to 'installing'.Once registration finishes, installation begins.InstallationA service worker fires itsinstall event after registration.install is only called once per service worker, and won't fire again until it's updated.A callback for the install event can be registered in the worker's scope with addEventListener:// /sw.jsself.addEventListener('install', (event) => { const cacheKey = 'MyFancyCacheName_v1'; event.waitUntil(caches.open(cacheKey).then((cache) => { // Add all the assets in the array to the 'MyFancyCacheName_v1' // `Cache` instance for later use. return cache.addAll([ '/css/global.bc7b80b7.css', '/css/home.fe5d0b23.css', '/js/home.d3cc4ba4.js', '/js/jquery.43ca4933.js' ]); }));});This creates a new Cache instance and precaches assets.We'll have plenty of opportunities to talk about precaching later,so let's focus on the role ofevent.waitUntil. event.waitUntil accepts a promise,and waits until that promise has been resolved.In