JS 9.0.2 - Notification Twice using onBackgroundMessage

[SylvainAssemat]

Hi

I'm in trouble testing the push event using the JS 9.0.2 (module) => via onBackgroundMessage in a service worker
I m aware that i dont have to send a notification in the payload so i just send data (via postman) :

{
   "to": "/topics/public",
    "data": {
        "body": "Notification in Body",
        "title": "Notification in Title",
        "url": "http://www.google.fr"
    }
}

When i customize my notification using self.registration.showNotification, i have 2 notification displaying.

This one : (This site has been updated in the background) should not appear
And my custom notification.

I have checked that the payload dont have any "notification" stuff.

I should miss something or maybe a bug ?

Thanks for any help

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[jbalidiong]

Hi @SylvainAssemat , thanks for the report. I was able to reproduce the behavior. Let me check what we can do for this issue or bring someone here that can provide more context about it. I’ll update this thread if I have any information to share.

[Feiyang1]

Sounds like the same issue as #3725. I thought it was fixed though - @zwu52

[zwu52]

@SylvainAssemat ,
could you paste your onBackrgoundMessage callback. So there is a timer ran for each onPush callback and the showNotification call needs to happen before the timer depletes. Asking because I suspecting yours is running slower for some reason.

[SylvainAssemat]

Hi all

@zwu52 , here is the service worker file including the onBackgroundMessage.

I have found a strange behaviour.
Today i test this double notification since my first issue , but i could not reproduce the bug.
I was so surprised !

But ...

When everything work well (tested many times), i begin to add just :

self.addEventListener('push', event => {
    console.log('[firebase-messaging-sw.js] Received PUSH event ', event);
});

What a bad idea ... , i could not make it work again since this modification.
Double notification is back :-(
(Even when i delete this listener)

Maybe there is something to investigate

import {
    initializeApp
} from "https://www.gstatic.com/firebasejs/9.1.2/firebase-app.js";

import {
    getMessaging,
    onBackgroundMessage
} from "https://www.gstatic.com/firebasejs/9.1.2/firebase-messaging-sw.js";


const firebaseApp = initializeApp({ 
	// MYCONFIG voluntarily hidden for github 
});

const messaging = getMessaging(firebaseApp);

onBackgroundMessage(messaging, (payload) => {
	console.log('[firebase-messaging-sw.js] Received background message ', payload);

	if (!(self.Notification && self.Notification.permission === 'granted')) {
        return;
    }
   
    self.registration.showNotification(payload.data.title, {
        body: payload.data.body,
        icon:  '/pwa/icon-512x512.png',
        badge: '/favicon.ico',
        tag: 'renotify',
		renotify: true,
		//actions: [{action: 'google', url: "https://www.google.fr"}]
    })
    .then(() => self.registration.getNotifications())
    .then(notifications => {
        setTimeout(() => notifications.forEach(notification => notification.close()), 3000);
    });

});

[zwu52]

The FCM SDK registers a onPush listener internally. Per Multiple identical event listeners, your listener could lead the FCM one being discarded. If that's the case, FCM SDK wouldn't function properly. But if you want to have your own onPush listener without the silent push warning, you also need to call showNotification inside. I doubt that's your goal so have you tried to clear the sites' cache when you removed your onPush listener?

Another tip is on using the onBackgroundMessage method is to always call showNotification 1st line to make sure the silent push check doesn't get triggered.