Updating a ServiceWorker only for new clients - javascript

I'm trying to make the update of my ServiceWorker work.
I have an old service worker, some windows are under it's control. Now there is a new version of the ServiceWorker. It get installed properly. But it does not get activated for new pages. My aim is to keep the old one for old pages and the new for every new tab/pages viewed.
Any idea how to accomplish this ?
Edit:
Is how I check that the the new service worker is not updated:
I have a sendMessage method:
sendMessage(message): Promise {
const channel = new MessageChannel();
const p1 = channel.port1;
const result = new Promise(resolve => {
p1.onmessage = ({ data }) => {
resolve(data);
};
});
serviceWorker.controller.postMessage(message, [channel.port2]);
return result;
}
Then I use it to check on page start
this.ready = this.sendMessage('version')
.then(version => {
if (version !== process.env.BUILD_NUMBER) {
console.log('$$ Version mismatch, reinstalling service worker');
throw new Error('build mismatch');
}
return serviceWorker.controller;
});
And I answer in the ServiceWorker
self.addEventListener('message', ({ data, ports }) => {
const client = ports[0];
if (data === 'version') {
client.postMessage(process.env.BUILD_NUMBER);
}
});
Edit
Adding:
event.waitUntil(self.clients.claim());
helps but it activate the ServiceWorker also for old clients.
Thanks

Calling self.skipWaiting() within a service worker's install event handler will cause the newly installed service worker to immediately activate, even if there's an existing, older service worker that's currently active for other clients. Without self.skipWaiting(), the newly installed service worker will remain in a waiting state until all other clients of the previous service worker have been closed.
Calling self.clients.claim() from inside the activate event handler is sometimes used as well, but only if you want the newly activated service worker to take control of already-open clients that are either uncontrolled, or controlled by an older version of the service worker. In your case, it sounds like you do not want that behavior, so you shouldn't call self.clients.claim().

Related

Blazor - Service worker not installing due to integrity check failure

I'm trying to setup PWA for my blazor application. I followed the instructions on: https://learn.microsoft.com/en-us/aspnet/core/blazor/progressive-web-app?view=aspnetcore-6.0&tabs=visual-studio
But when I open the deployed website the following error occurs:
Failed to find a valid digest in the 'integrity' attribute for resource 'domain/manifest.json' with computed SHA-256 integrity 'uDWnAIEnaz9hFx7aEpJJVS1a+QB/W7fMELDfHWSOFkQ='. The resource has been blocked.
Unknown error occurred while trying to verify integrity.
service-worker.js:22
Uncaught (in promise) TypeError: Failed to fetch
at service-worker.js:22:54
at async onInstall (service-worker.js:22:5)
In the source file this happens here:
async function onInstall(event) {
console.info('Service worker: Install');
// Fetch and cache all matching items from the assets manifest
const assetsRequests = self.assetsManifest.assets
.filter(asset => offlineAssetsInclude.some(pattern => pattern.test(asset.url)))
.filter(asset => !offlineAssetsExclude.some(pattern => pattern.test(asset.url)))
.map(asset => new Request(asset.url, { integrity: asset.hash, cache: 'no-cache' }));
await caches.open(cacheName).then(cache => cache.addAll(assetsRequests));
}
I think the error is happening since the entry in assetsRequests has a wrong hash and the resource is blocked. If I remove the file from the service-worker-assets.js, the service worker installs and the PWA can be used. But I think this is not a reliable solution.
This also happens sometimes for the appsettings.json. In the service-worker-assets.js I can find the following entry:
{
"hash": "sha256-+Py0\/ezc+0k1sm\/aruGPrVhS1jOCTfPKMhOSS+bunek=",
"url": "manifest.json"
},
So the hash does not seem to match. Where does the browser take the wrong hash from? How can I fix this so it does match?
Also it seems that the app is caching older files sometimes. Even when I do a "Reset Cache & Hard Reload" in Chrome the service-worker.js file is still an older version. Any idea how to fix this as well, since it might be related?
Edit: I was also checking this solution: https://stackoverflow.com/a/69935118/11385442. But in the mentioned blazor.boot.json I cannot find any reference to the manifest.json or the appsettings.json. Only Dlls are listed. So the problem only seems to relate to files not listed in blazor.boot.json.
Edit2: What I can see on the webserver is that the following files are published:
appsettings.json
appsettings.json.br
appsettings.json.gzip
So it seems like compressed version are added. Also the appsettings.json has a different size than the one in the solution. My guess is that somewhere in the build or release pipeline (Azure) the files are modified. But even when I copy the appsettings.json manually to the webserver the error still occurs. I was following Information provided here: https://learn.microsoft.com/en-us/aspnet/core/blazor/host-and-deploy/webassembly?view=aspnetcore-5.0
(Diagnosing integrity problems)
My guess was right. The appsettings.json was modified probably due to the xml transformation in the azure pipeline. My current solution is to exclude integrity validation for such resources as described in the following answer: Error loading appsettings.Production.json due to digest integrity issue
Also I changed the "sw-registrator.js" mentioned in the original posts comments to work correctly, because it didn't load the new files into the cache:
function invokeServiceWorkerUpdateFlow(registration) {
if (confirm("New version available, reload?") == true) {
if (registration.waiting) {
console.info(`Service worker registrator: Post skip_waiting...`);
// let waiting Service Worker know it should became active
registration.waiting.postMessage('SKIP_WAITING')
}
}
}
function checkServiceWorkerUpdate(registration) {
setInterval(() => {
console.info(`Service worker registrator: Checking for update... (scope: ${registration.scope})`);
registration.update();
}, 60 * 1000); // 60000ms -> check each minute
}
// check if the browser supports serviceWorker at all
if ('serviceWorker' in navigator) {
// wait for the page to load
window.addEventListener('load', async () => {
// register the service worker from the file specified
const registration = await navigator.serviceWorker.register('/service-worker.js');
// ensure the case when the updatefound event was missed is also handled
// by re-invoking the prompt when there's a waiting Service Worker
if (registration.waiting) {
invokeServiceWorkerUpdateFlow(registration);
}
// detect Service Worker update available and wait for it to become installed
registration.addEventListener('updatefound', () => {
if (registration.installing) {
// wait until the new Service worker is actually installed (ready to take over)
registration.installing.addEventListener('statechange', () => {
if (registration.waiting) {
// if there's an existing controller (previous Service Worker), show the prompt
if (navigator.serviceWorker.controller) {
invokeServiceWorkerUpdateFlow(registration);
} else {
// otherwise it's the first install, nothing to do
console.log('Service worker registrator: Initialized for the first time.')
}
}
});
}
});
checkServiceWorkerUpdate(registration);
let refreshing = false;
// detect controller change and refresh the page
navigator.serviceWorker.addEventListener('controllerchange', () => {
console.info(`Service worker registrator: Refreshing app... (refreshing: ${refreshing})`);
if (!refreshing) {
window.location.reload();
refreshing = true
}
});
});
}
else
{
console.error(`Service worker registrator: This browser doesn't support service workers.`);
}
Also I had to add this in service-worker.js:
self.addEventListener('message', (event) => {
console.info('Service worker: Message received');
if (event.data === 'SKIP_WAITING') {
// Cause the service worker to update
self.skipWaiting();
}
});
This code was mostly taken from https://whatwebcando.today/articles/handling-service-worker-updates/

Service Worker not stopping initial requests and only appears to be used once

I asked a question last week about this and got a very helpful answer but I am still struggling to get this working as it is supposed to, although at this point I'm not entirely sure what I've been asked to do is possible.
So this service worker is supposed to activate when ?testMode=true is added to the URL and this seems to be happening okay. The service worker is then supposed to intercept specific requests before they happen and then redirect it to mock data instead. What I have got at the moment will store the mock data and call it when specific requests are made but it doesn't actually stop the initial request from happening as it still appears within the network tab.
So for example if the request contains /units/all?availability=Active&roomTypeHandle=kitchens, the service worker is meant to intercept this and instead of that request going through, mock-data/unitData.json is supposed to be used instead.
This is what I have so far:
TestMode.ts
class TestMode {
constructor() {
if (!this.isEnabled()) {
return;
}
if (!('serviceWorker' in navigator)) {
console.log('Browser does not support service workers');
return;
}
this.init();
}
private init(): void {
navigator.serviceWorker
.register('planner-worker/js/worker.min.js')
.then(this.handleRegistration)
.catch((error) => { throw new Error('Service Worker registration failed: ' + error.message); });
navigator.serviceWorker.addEventListener('message', event => {
// event is a MessageEvent object
console.log(`The service worker sent me a message: ${event.data}`);
});
navigator.serviceWorker.ready.then( registration => {
if (!registration.active) {
console.log('failed to communicate')
return;
}
registration.active.postMessage("Hi service worker");
});
}
private handleRegistration(registration: ServiceWorkerRegistration): void {
registration.update();
console.log('Registration successful, scope is:', registration.scope);
}
private isEnabled(): boolean {
return locationService.hasParam('testMode');
}
}
export default new TestMode();
serviceWorker.js
const CACHE_NAME = 'mockData-cache';
const MOCK_DATA = {
'/units/all?availability=Active&roomTypeHandle=kitchens': 'mock-data/unitData.json',
'/frontal-ranges/kitchens?' : 'mock-data/kitchensData.json',
'/carcase-ranges/?availability=Active&roomTypeHandle=kitchens' : 'mock-data/carcaseRangesData.json',
'/products/830368/related?roomTypeHandle=kitchens&productStateHandle=Active&limit=1000&campaignPhaseId=183&retailStore=Finishing%20Touches%20%28Extra%29'
: 'mock-data/relatedItems.json'
};
self.addEventListener('install', event => {
console.log('Attempting to install service worker and cache static assets');
event.waitUntil(
caches.open(CACHE_NAME)
.then(cache => {
return cache.addAll(Object.values(MOCK_DATA));
})
);
});
self.addEventListener('activate', function(event) {
return self.clients.claim();
});
self.addEventListener('fetch', (event) => {
const url = new URL(event.request.url);
const pathAndQuery = url.pathname + url.search;
if (pathAndQuery in MOCK_DATA) {
const cacheKey = MOCK_DATA[pathAndQuery];
event.respondWith(
caches.match(cacheKey, {
cacheName: CACHE_NAME,
})
);
}
});
Another thing that happens which I'm not sure how to get around is that the fetch event only happens once. By that I mean that when a change is made to serviceWorker.js, the mock data is stored in the cache and the files appear in the network tab of dev tools, but if I refresh the page, or close it and reopen in another tab, the mock data is no longer in the network tab and it's as if the service worker is not being used at all. How can I update this so that it's always used? I can see in the console log that the service worker is registered, but it just don't seem to get used.
Apologies if I shouldn't be asking 2 questions in 1 post, just really not sure how to solve my issue. Thanks in advance for any guidance.
Turns out my issue was a scope one. Once moving where the service worker was stored it started working as intended. Realised this was the case as I figured out the fetch event wasn't actually firing.

http-server net serving the fresh js file

I haven't used http-server npm module before!
i was just getting starting with using service worker by creating an example app using this blog as a source
In this the author have used http-server to demonstrate service worker!
From the blog, I copied the code snippet to check if chrome is supported
const check = () => {
if (!('serviceWorker' in navigator)) {
throw new Error('No Service Worker support!')
}
if (!('PushManager' in window)) {
throw new Error('No Push API Support!')
}
console.log('Everything works fine')
}
const main = () => {
check()
}
main()
Notice the console.log('Everything works fine')
Now, as i proceeded with Article, I changed my main.js as instructed to this
const check = () => {
if (!('serviceWorker' in navigator)) {
throw new Error('No Service Worker support!')
}
if (!('PushManager' in window)) {
throw new Error('No Push API Support!')
}
console.log(`Browser supports Pushmanager and Service worker`)
}
// Async so we can use await
const main = async () => {
check()
const swRegistration = await registerServiceWorker();
}
//To run service worker we need to first register service worker
//Registering Service Worker
const registerServiceWorker = async () => {
const swRegistration = await navigator.serviceWorker.register('service.js'); //notice the file name
return swRegistration;
}
but when I go the page, it keeps logging this from our first code snippet in the console
Everything works fine
I checked the main.js, and it appears the server is still serving the previous main.js instead of new one.
If I go manually to my file and open it without the server, the main.js shows my new code changes.
I have tried turning of the server (using ctrl/cmd + c) and restarting it again but no help.
Can someone help me out in fixing it?
Looks like http-server tells the browser to cache pages for an hour by default:
-c Set cache time (in seconds) for cache-control max-age header, e.g. -c10 for 10 seconds (defaults to '3600'). To disable caching, use -c-1.
Restart the server with http-server -c-1, then do a hard refresh in the browser (Ctrl/Cmd+Shift+R in Firefox or Chrome).

Changing the name of a service worker?

I'm trying to figure out what happens if I have a service worker registered on a live site called sw.js and then I rename the service worker to service-worker.js. Now the old one isn't found but it is still showing the old cached version.
How long does it take for it to register the new renamed service worker or how does this work at all?
Edit
This is how I have register the service worker in a react application:
componentDidMount() {
if ("serviceWorker" in navigator) {
navigator.serviceWorker
.register("/service-worker.js")
.then(registration => {
console.log("service worker registration successful: ", registration);
})
.catch(err => {
console.warn("service worker registration failed", err.message);
});
}
}
The newly created service worker (renamed) cannot take over the old one because the old one is still active and controlling the client.
the new service worker(renamed one) will wait until the existing worker is controlling zero clients.
Now imagine a service worker sw.js installed and active (controlling the client),
Chrome will visualize the process for you like this
1. The service worker is registered and active
2. Now let's rename the service worker file to sw2.js
You can see that chrome is telling you that something has changed about the service worker. but the current one will keep controlling the client until you force the new one to take control by clicking on the skipWaitting button or by flushing your cache. clicking on the button will cause the sw2.js to take controll over the sw1.js
Now if you need to do this programmatically, you can do it in the install event inside your service worker by calling self.skipWaiting().
self.addEventListener('install', (e) => {
let cache = caches.open(cacheName).then((c) => {
c.addAll([
// my files
]);
});
self.skipWaiting();
e.waitUntil(cache);
});
The following animated image from Jake Archibald's article The Service Worker Lifecycle can make the idea more clear.
You have to update the instance creation code to reflect this change where your shared worker is being initialized and used, for example your current code would look like
var worker = new SharedWorker("ws.js");
That will need to be updated to
var worker = new SharedWorker("service-worker.js");
I was able to solve it by setting up a server which listens to both /service-worker.js and /sw.js get requests.
Since the service worker was renamed from sw.js to service-worker.js it was not finding the old service worker at http://example.com/sw.js so what I did was the following:
createServer((req, res) => {
const parsedUrl = parse(req.url, true);
const { pathname } = parsedUrl;
// new service worker
if (pathname === "/service-worker.js") {
const filePath = join(__dirname, "..", pathname);
app.serveStatic(req, res, filePath);
// added new endpoint to fetch the new service worker but with the
// old path
} else if (pathname === "/sw.js") {
const filePath = join(__dirname, "..", "/service-worker.js");
app.serveStatic(req, res, filePath);
} else {
handle(req, res, parsedUrl);
}
}).listen(port, err => {
if (err) throw err;
console.log(`> Ready on http://localhost:${port}`);
});
As you can see, I added a second path to serve the same service worker but with the /sw.js endpoint, one for the old sw.js and the other one for the newer service-worker.js.
Now when old visitors that have the old active sw.js will download the newer one and upon revisit, they will automatically fetch the newer renamed service-worker.js service worker.

Refresh page after load on cache-first Service Worker

I'm currently considering adding service workers to a Web app I'm building.
This app is, essentially, a collection manager. You can CRUD items of various types and they are usually tightly linked together (e.g. A hasMany B hasMany C).
sw-toolbox offers a toolbox.fastest handler which goes to the cache and then to the network (in 99% of the cases, cache will be faster), updating the cache in the background. What I'm wondering is how you can be notified that there's a new version of the page available. My intent is to show the cached version and, then, if the network fetch got a newer version, to suggest to the user to refresh the page in order to see the latest edits. I saw something in a YouTube video a while ago but the presenter gives no clue of how to deal with this.
Is that possible? Is there some event handler or promise that I could bind to the request so that I know when the newer version is retrieved? I would then post a message to the page to show a notification.
If not, I know I can use toolbox.networkFirst along with a reasonable timeout to make the pages available even on Lie-Fi, but it's not as good.
I just stumbled accross the Mozilla Service Worker Cookbooj, which includes more or less what I wanted: https://serviceworke.rs/strategy-cache-update-and-refresh.html
Here are the relevant parts (not my code: copied here for convenience).
Fetch methods for the worker
// On fetch, use cache but update the entry with the latest contents from the server.
self.addEventListener('fetch', function(evt) {
console.log('The service worker is serving the asset.');
// You can use respondWith() to answer ASAP…
evt.respondWith(fromCache(evt.request));
// ...and waitUntil() to prevent the worker to be killed until the cache is updated.
evt.waitUntil(
update(evt.request)
// Finally, send a message to the client to inform it about the resource is up to date.
.then(refresh)
);
});
// Open the cache where the assets were stored and search for the requested resource. Notice that in case of no matching, the promise still resolves but it does with undefined as value.
function fromCache(request) {
return caches.open(CACHE).then(function (cache) {
return cache.match(request);
});
}
// Update consists in opening the cache, performing a network request and storing the new response data.
function update(request) {
return caches.open(CACHE).then(function (cache) {
return fetch(request).then(function (response) {
return cache.put(request, response.clone()).then(function () {
return response;
});
});
});
}
// Sends a message to the clients.
function refresh(response) {
return self.clients.matchAll().then(function (clients) {
clients.forEach(function (client) {
// Encode which resource has been updated. By including the ETag the client can check if the content has changed.
var message = {
type: 'refresh',
url: response.url,
// Notice not all servers return the ETag header. If this is not provided you should use other cache headers or rely on your own means to check if the content has changed.
eTag: response.headers.get('ETag')
};
// Tell the client about the update.
client.postMessage(JSON.stringify(message));
});
});
}
Handling of the "resource was updated" message
navigator.serviceWorker.onmessage = function (evt) {
var message = JSON.parse(evt.data);
var isRefresh = message.type === 'refresh';
var isAsset = message.url.includes('asset');
var lastETag = localStorage.currentETag;
// ETag header usually contains the hash of the resource so it is a very effective way of check for fresh content.
var isNew = lastETag !== message.eTag;
if (isRefresh && isAsset && isNew) {
// Escape the first time (when there is no ETag yet)
if (lastETag) {
// Inform the user about the update.
notice.hidden = false;
}
//For teaching purposes, although this information is in the offline cache and it could be retrieved from the service worker, keeping track of the header in the localStorage keeps the implementation simple.
localStorage.currentETag = message.eTag;
}
};

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