I have built a React progressive web application that makes use of service workers.
The service worker gets registered and is activated:
I have been trying to detect the "activate" event using this:
service-worker.js
navigator.serviceWorker.addEventListener("activate", function (event) {
console.log("service worker activated");
});
I added that at the end of the service-worker file. But, this event never gets triggered and I have no idea why.
I also tried to implement push notifications and trigger the from the backend. For this, I needed a "push" event listener that would listen to these events from the server:
navigator.serviceWorker.addEventListener("push", async function (event) {
const message = await event.data.json();
let { title, description, image } = message;
await event.waitUntil(showPushNotification(title, description, image));
});
This is how showPushNotification is defined:
export function showPushNotification(title, description, image) {
if (!("serviceWorker" in navigator)) {
console.log("Service Worker is not supported in this browser");
return;
}
navigator.serviceWorker.ready.then(function (registration) {
registration.showNotification(title, {
body: description,
icon: image,
actions: [
{
title: "Say hi",
action: "Say hi",
},
],
});
});
}
I tested calling that function manually and it successfully triggerss a push notification.
This is the server code that triggers the push notification:
const sendPushNotification = async (user_id, title, description, image) => {
const search_option = { user: user_id };
const users_subscriptions = await PushNotificationSubscription.find(
search_option
);
const number_of_users_subscriptions = users_subscriptions.length;
const options = {
vapidDetails: {
subject: "mailto:xxxx#xxxx.com",
publicKey: VAPID_PUBLIC_KEY,
privateKey: VAPID_PRIVATE_KEY,
},
};
let push_notif_sending_results = {};
for (let i = 0; i < number_of_users_subscriptions; i++) {
const user_subscription = users_subscriptions[i];
await webPush
.sendNotification(
user_subscription,
JSON.stringify({
title,
description,
image,
}),
options
)
.then((notif_send_result) => {
push_notif_sending_results[i] = { success: notif_send_result };
})
.catch((error) => {
push_notif_sending_results[i] = { error: error };
});
}
return push_notif_sending_results;
};
This is the part responsible for sending the push notification:
webPush
.sendNotification(
user_subscription,
JSON.stringify({
title,
description,
image,
}),
options
)
And it's successfully executed as it returns a 201 HTTP response.
So the "push" event listener is supposed to detect it and trigger a push notification.
I think everything regarding the push notification has been successfully implementing and the problem is how the "push" event listener is added since the "activate" event listener also doesn't work.
So I tried moving the two event listeners here right after the registration of the service worker is successful:
function registerValidSW(swUrl, config) {
navigator.serviceWorker.register(swUrl).then((registration) => {
registration.addEventListener("activate", (event) => {
console.log(
"🚀 ~ file: serviceWorker.js:159 ~ navigator.serviceWorker.register ~ event",
event
);
});
registration.addEventListener("push", async function (event) {
const message = await event.data.json();
let { title, description, image } = message;
await event.waitUntil(
showPushNotification(title, description, image)
);
});
});
}
But, it's still the same result.
Neither the "push" nor the "activate" event listeners get triggered.
Any idea what's going on?
Here's the whole service-worker file:
service-worker.js
import axios from "axios";
const isLocalhost = Boolean(
window.location.hostname === "localhost" ||
// [::1] is the IPv6 localhost address.
window.location.hostname === "[::1]" ||
// 127.0.0.0/8 are considered localhost for IPv4.
window.location.hostname.match(
/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
)
);
export function register(config) {
if (process.env.NODE_ENV === "production" && "serviceWorker" in navigator) {
// The URL constructor is available in all browsers that support SW.
const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href);
if (publicUrl.origin !== window.location.origin) {
// Our service worker won't work if PUBLIC_URL is on a different origin
// from what our page is served on. This might happen if a CDN is used to
// serve assets;
return;
}
window.addEventListener("load", () => {
const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`;
if (isLocalhost) {
// This is running on localhost. Let's check if a service worker still exists or not.
checkValidServiceWorker(swUrl, config);
// Add some additional logging to localhost, pointing developers to the
// service worker/PWA documentation.
} else {
// Is not localhost. Just register service worker
console.log(
"Is not localhost. Just register a service worker, by calling registerValidSW"
);
registerValidSW(swUrl, config);
}
});
}
}
async function subscribeToPushNotifications(serviceWorkerReg) {
let subscription = await serviceWorkerReg.pushManager.getSubscription();
if (subscription === null) {
const dev_public_vapid_key = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
const prod_public_vapid_key =
"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
const public_vapid_key = isLocalhost
? dev_public_vapid_key
: prod_public_vapid_key;
subscription = await serviceWorkerReg.pushManager.subscribe({
userVisibleOnly: true,
applicationServerKey: public_vapid_key,
});
axios
.post("/api/push_notif_subscription/subscribe", subscription)
.then((response) => {})
.catch((error) => {});
}
}
export function showPushNotification(title, description, image) {
if (!("serviceWorker" in navigator)) {
console.log("Service Worker is not supported in this browser");
return;
}
navigator.serviceWorker.ready.then(function (registration) {
registration.showNotification(title, {
body: description,
icon: image,
actions: [
{
title: "Say hi",
action: "Say hi",
},
],
});
});
}
function registerValidSW(swUrl, config) {
navigator.serviceWorker.register(swUrl).then((registration) => {
subscribeToPushNotifications(registration);
registration.onupdatefound = () => {
const installingWorker = registration.installing;
if (!installingWorker) {
return;
}
installingWorker.onstatechange = () => {
if (installingWorker.state === "installed") {
if (navigator.serviceWorker.controller) {
// At this point, the updated precached content has been fetched,
// but the previous service worker will still serve the older
// content until all client tabs are closed.
// Execute callback
if (config && config.onUpdate) {
config.onUpdate(registration);
}
} else {
// At this point, everything has been preached.
// It's the perfect time to display a
// "Content is cached for offline use." message.
// Execute callback
if (config && config.onSuccess) {
config.onSuccess(registration);
}
}
}
};
};
});
}
function checkValidServiceWorker(swUrl, config) {
// Check if the service worker can be found. If it can't reload the page.
fetch(swUrl, {
headers: { "Service-Worker": "script" },
}).then((response) => {
// Ensure the service worker exists, and that we really are getting a JS file.
const contentType = response.headers.get("content-type");
if (
response.status === 404 ||
(!!contentType && contentType.indexOf("javascript") === -1)
) {
// No service worker found. Probably a different app. Reload the page.
navigator.serviceWorker.ready.then((registration) => {
registration.unregister().then(() => {
window.location.reload();
});
});
} else {
// Service worker found. Proceed as normal.
console.log("Service worker found, calling registerValidSW");
registerValidSW(swUrl, config);
}
});
}
export function unregister() {
if ("serviceWorker" in navigator) {
navigator.serviceWorker.ready.then((registration) => {
registration.unregister();
});
}
}
navigator.serviceWorker.addEventListener("activate", function (event) {
console.log("service worker activated");
});
navigator.serviceWorker.addEventListener("push", async function (event) {
const message = await event.data.json();
let { title, description, image } = message;
await event.waitUntil(showPushNotification(title, description, image));
});
The events "push" and "activate" are part of the ServiceWorkerGlobalScope as within the Service Worker API.
Push notifications must be handled within the service worker itself.
Therefore only the service worker can register an "activate" event listener.
The same applies for a "push" listener.
Specially in terms of the "push" listener this makes sense.
The idea of push events is to receive them, even if the main app (in this case the website) has been closed.
The service worker is an exception, as it even runs without the page being loaded.
Therefore move the "push" event into your service worker.
Your code (within the service worker) may look like this:
this.addEventListener("push", async function (event) {
const message = await event.data.json();
let { title, description, image } = message;
await event.waitUntil(showPushNotification(title, description, image));
});
function showPushNotification(title, description, image) {
registration.showNotification(title, {
body: description,
icon: image,
actions: [
{
title: "Say hi",
action: "Say hi",
},
],
});
}
The rest seems fine to me.
Update (Some more explanation)
I took a more careful look at your service-worker.js and it seems it contains general methods for registering the service worker.
As mentioned above the main app and the service worker are two completely separate chunks of code, running in different spaces. So this means everything which is not supposed to run in the service worker itself must be put outside of the service-worker.js. The service worker (in your case) should only contain the code for handling push notifications. It's important that you do not include the "service-worker.js" within your application.
In your case, you may seperate these functions into service-worker-register.js which contain all functions which are for managing the service worker registration but should not be executed within the service worker itself (isLocalhost, register, subscribeToPushNotifications, registerValidSW, checkValidServiceWorker, and unregister). Please note the code snippet from above and make changes accordingly to the code left within the service worker.
MDN has a pretty in depth tutorial on service workers (and there are a lot more) I recommend having a look at:
developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API/Using_Service_Workers
I want to update PWA application when new content is available. Since we can't access DOM from service worker, how can I exactly do that?
The service worker correctly recognize the new content, but I can't bind a hook or context to show my modal or update button in react. Any help?
service worker register and onUpdate function:
function RegisterValidSW(swUrl, config) {
navigator.serviceWorker
.register(swUrl)
.then((registration) => {
registration.onupdatefound = () => {
const installingWorker = registration.installing;
if (installingWorker == null) {
return;
}
installingWorker.onstatechange = () => {
if (installingWorker.state === 'installed') {
if (navigator.serviceWorker.controller) {
// At this point, the updated precached content has been fetched,
// but the previous service worker will still serve the older
// content until all client tabs are closed.
// setUpdate(true);
// registration.waiting.postMessage({ type: 'SKIP_WAITING' });
console.log(
'New content is available and will be used when all ' +
'tabs for this page are closed. See https://cra.link/PWA.'
);
// Execute callback
if (config && config.onUpdate) {
config.onUpdate(registration);
}
} else {
// At this point, everything has been precached.
// It's the perfect time to display a
// "Content is cached for offline use." message.
console.log('Content is cached for offline use.');
// Execute callback
if (config && config.onSuccess) {
config.onSuccess(registration);
}
}
}
};
};
})
.catch((error) => {
console.error('Error during service worker registration:', error);
});
}
this function is in the serviceWorkerRegistration.js file.
We can add registration.waiting.postMessage({ type: 'SKIP_WAITING' }); function to call skipWaiting but it doesn't wait for user interaction and can't reload the page. how can I solve that?
You can try passing in an onUpdate function when you register the service worker. In that function send a SKIP_WAITING message to the service worker followed a page reload.
onUpdate: (registration) => {
console.log("SW: sending SKIP_WAITING message to get updated serviceworker to take effect now (without manual restart)")
// Old serviceworker will be stopped/new serviceworker started without reload
registration.waiting.postMessage({type: 'SKIP_WAITING'})
window.location.reload()
}
Your server worker should have SKIP_WAITING message hander. Something like this:
self.addEventListener('message', (event) => {
console.log("SW: received message event = "+JSON.stringify(event))
if (event.data && event.data.type === 'SKIP_WAITING') {
self.skipWaiting();
}});
This is working for me.
What I am still struggling with is how to get the app updated if the user leaves the app open. As in,
User browses to PWA url
User adds to Home Screen
User closes browser tab
User opens PWA from Home Screen
and just leaves it open forever and ever...
This should probably go in a new question, but I thought it might be relevant to your use case.
I am totally new to service-workers! I am having a react site running in the localhost and about to be deployed. I am following the code specified here.
const isLocalhost = Boolean(
window.location.hostname === 'localhost' ||
// [::1] is the IPv6 localhost address.
window.location.hostname === '[::1]' ||
// 127.0.0.1/8 is considered localhost for IPv4.
window.location.hostname.match(
/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
)
)
export default function register () {
if (process.env.NODE_ENV === 'production' && 'serviceWorker' in navigator) {
// The URL constructor is available in all browsers that support SW.
const publicUrl = new URL(process.env.PUBLIC_URL, window.location)
if (publicUrl.origin !== window.location.origin) {
// Our service worker won't work if PUBLIC_URL is on a different origin
// from what our page is served on. This might happen if a CDN is used to
// serve assets; see https://github.com/facebookincubator/create-react-app/issues/2374
return
}
window.addEventListener('load', () => {
const swUrl = `${process.env.PUBLIC_URL}/service-worker.js`
if (!isLocalhost) {
// Is not local host. Just register service worker
registerValidSW(swUrl)
} else {
// This is running on localhost. Lets check if a service worker still exists or not.
checkValidServiceWorker(swUrl)
}
})
}
}
function registerValidSW (swUrl) {
navigator.serviceWorker
.register(swUrl)
.then(registration => {
registration.onupdatefound = () => {
const installingWorker = registration.installing
installingWorker.onstatechange = () => {
if (installingWorker.state === 'installed') {
if (navigator.serviceWorker.controller) {
// At this point, the old content will have been purged and
// the fresh content will have been added to the cache.
// It's the perfect time to display a "New content is
// available; please refresh." message in your web app.
console.log('New content is available; please refresh.')
} else {
// At this point, everything has been precached.
// It's the perfect time to display a
// "Content is cached for offline use." message.
console.log('Content is cached for offline use.')
}
}
}
}
})
.catch(error => {
console.error('Error during service worker registration:', error)
})
}
function checkValidServiceWorker (swUrl) {
// Check if the service worker can be found. If it can't reload the page.
fetch(swUrl)
.then(response => {
// Ensure service worker exists, and that we really are getting a JS file.
if (
response.status === 404 ||
response.headers.get('content-type').indexOf('javascript') === -1
) {
// No service worker found. Probably a different app. Reload the page.
navigator.serviceWorker.ready.then(registration => {
registration.unregister().then(() => {
window.location.reload()
})
})
} else {
// Service worker found. Proceed as normal.
registerValidSW(swUrl)
}
})
.catch(() => {
console.log(
'No internet connection found. App is running in offline mode.'
)
})
}
export function unregister () {
if ('serviceWorker' in navigator) {
navigator.serviceWorker.ready.then(registration => {
registration.unregister()
})
}
}
This only works in Production but, I want the offline-site to run in the localhost and also cache only the base route ie /. I don't want to cache any other pages.
Any help is greatly appreciated !
Thanks!
Here's what you could do.
//this is your settings component
export default function Settings(props) {
const [offline, setOffline] = useState(false);
useEffect(() => {
if(!navigator.onLine) setOffline(true);
}, []);
return (
<>
{offline && (
<div>You are offline please connect to the internet</div>
<button onClick={() => window.location.reload(true)}>Refresh</button>
)}
{!offline && (
<div>This is my actual settings page</div>
)}
</>
);
}
There you go, you have conditional rendering of your settings, on the basis of the user being offline. Or you could also try alerting the user when the fetch fails(the user is offline). Like below:
export default function Settings(props) {
const handleAPICall = () => {
fetch(YOUR_API_ENDPOINT).then(res => res.json()).then(data => useData(data)).catch(err => {
setOffline(true);
});
}
return (
<>
{offline && (
<Alert timeout={'3s'}>You are offline please connect to the internet</Alert>
)}
<div>
<p>This is my actual settings page</p>
<button onClick={handleAPICall}>Fetch data</button>
</div>
</>
);
</>
);
}
I hope you find one of these approaches applicable to you. See, making only a part of your web app offline was never the right approach to your problem in the first place. Sometimes it gets hard to ask the right questions because you yourself don't know what you want. But we have to keep grinding.
I'm working on implementing the service worker concept in react and I have added all the configurations suggested in the Link making-a-progressive-web-app but the problem here is that for displaying the new content (when the network changed from offline to online), I've to display user to message like 'New content is available once existing tabs are closed.' So here we're forcing the user to close the page for displaying new content. Even the refresh option is also not working here.
Check the below method - (This is a method created when we build react app using create-react-app, the method can be found in react-app/service-worker.js)
function registerValidSW(swUrl, config) {
navigator.serviceWorker
.register(swUrl)
.then(registration => {
registration.onupdatefound = () => {
const installingWorker = registration.installing;
if (installingWorker == null) {
return;
}
installingWorker.onstatechange = () => {
if (installingWorker.state === 'installed') {
if (navigator.serviceWorker.controller) {
// At this point, the updated precached content has been fetched,
// but the previous service worker will still serve the older
// content until all client tabs are closed.
console.log(
'New content is available and will be used when all ' +
'tabs for this page are closed. See'
);
// Execute callback
if (config && config.onUpdate) {
config.onUpdate(registration);
}
} else {
// At this point, everything has been precached.
// It's the perfect time to display a
// "Content is cached for offline use." message.
console.log('Content is cached for offline use.');
// Execute callback
if (config && config.onSuccess) {
config.onSuccess(registration);
}
}
}
};
};
})
.catch(error => {
console.error('Error during service worker registration:', error);
});
}
You can clearly see the console
New content is available and will be used when all tabs for this page are closed.
What is the best way to achieve this? So only refreshing the page, we can update the previous stored cache.
hi I had the same problem while working with PWA you can the following code in the where ever you have registered the service-worker
serviceWorker.register({
onUpdate: registration => {
alert('New version available! Ready to update?');
window.location.reload();
if (registration && registration.waiting) {
registration.waiting.postMessage({ type: 'SKIP_WAITING' });
}
}
});
I'm pretty new to react and I'm trying to implement a service worker at the moment.
Actually I always get an error 'Uncaught SyntaxError: Unexpected token 'export'' in my "serviceworker.js" class.
Here's my main.tsx file.
import React from 'react';
import ReactDOM from 'react-dom';
import 'bootstrap/dist/css/bootstrap.css';
import App from './app/app';
import * as registerServiceWorker from './serviceworker/serviceworker';
ReactDOM.render(<App />, document.getElementById('root'));
registerServiceWorker.register();
And thats my "serviceworker.js" file.
const isLocalhost = Boolean(
window.location.hostname === 'localhost' ||
// [::1] is the IPv6 localhost address.
window.location.hostname === '[::1]' ||
// 127.0.0.1/8 is considered localhost for IPv4.
window.location.hostname.match(
/^127(?:\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)){3}$/
)
)
export function register(config) {
if ('serviceWorker' in navigator) {
// The URL constructor is available in all browsers that support SW.
// const publicUrl = new URL(process.env.PUBLIC_URL, window.location.href);
// if (publicUrl.origin !== window.location.origin) {
// // Our service worker won't work if PUBLIC_URL is on a different origin
// // from what our page is served on. This might happen if a CDN is used to
//
// return;
// }
window.addEventListener('load', () => {
const swUrl = `/serviceworker/serviceworker.js`;
if (isLocalhost) {
// This is running on localhost. Let's check if a service worker still exists or not.
checkValidServiceWorker(swUrl, config);
// Add some additional logging to localhost, pointing developers to the
// service worker/PWA documentation.
navigator.serviceWorker.ready.then(() => {
console.log(
'This web app is being served cache-first by a service ' +
'worker. To learn more, '
);
});
} else {
// Is not localhost. Just register service worker
registerValidSW(swUrl, config);
}
});
}
}
function registerValidSW(swUrl, config) {
navigator.serviceWorker
.register(swUrl)
.then(registration => {
registration.onupdatefound = () => {
const installingWorker = registration.installing;
if (installingWorker == null) {
return;
}
installingWorker.onstatechange = () => {
if (installingWorker.state === 'installed') {
if (navigator.serviceWorker.controller) {
// At this point, the updated precached content has been fetched,
// but the previous service worker will still serve the older
// content until all client tabs are closed.
console.log(
'New content is available and will be used when all ' +
'tabs for this page are closed. See /CRA-PWA.'
);
// Execute callback
if (config && config.onUpdate) {
config.onUpdate(registration);
}
} else {
// At this point, everything has been precached.
// It's the perfect time to display a
// "Content is cached for offline use." message.
console.log('Content is cached for offline use.');
// Execute callback
if (config && config.onSuccess) {
config.onSuccess(registration);
}
}
}
};
};
})
.catch(error => {
console.error('Error during service worker registration:', error);
});
}
function checkValidServiceWorker(swUrl, config) {
// Check if the service worker can be found. If it can't reload the page.
fetch(swUrl)
.then(response => {
// Ensure service worker exists, and that we really are getting a JS file.
const contentType = response.headers.get('content-type');
if (
response.status === 404 ||
(contentType === null)
) {
// No service worker found. Probably a different app. Reload the page.
navigator.serviceWorker.ready.then(registration => {
registration.unregister().then(() => {
window.location.reload();
});
});
} else {
// Service worker found. Proceed as normal.
registerValidSW(swUrl, config);
}
})
.catch(() => {
console.log(
'No internet connection found. App is running in offline mode.'
);
});
}
export function unregister() {
if ('serviceWorker' in navigator) {
navigator.serviceWorker.ready.then(registration => {
registration.unregister();
});
}
}
Any idea what I did wrong here?
I already added Babel as suggested in this thread react export Unexpected token but the error didn't disappear.
I already tried to export it via modules.export, but no sucess either.
Thanks in advance!
EDIT:
Thats what my ".babelrc" looks like:
{
"presets": ["#babel/preset-react"],
"plugins": [
"babel-plugin-transform-export-extensions",
"transform-es2015-modules-commonjs"
]
}
Thats what my ".babelrc" looks like:
{
"presets": ["#babel/preset-react"],
"plugins": [
"babel-plugin-transform-export-extensions",
"transform-es2015-modules-commonjs"
]
}
This problem occurs because you are trying to use the same file as the service worker you are registering it with. Because of this, the browser cannot figure out which service worker features you need.
Use for example this content for service-worker.js in your public folder:
self.addEventListener('push', (event) => {
const data = event.data.json();
console.log('New notification', data);
event.waitUntil(
self.registration.showNotification(data.title, {
body: data.description,
icon: data.icon,
})
);
});