Develop Reference

Expo: don't show notification if app is open in foreground

I am developing a react-native messaging app with Expo. Every time a user receives a new message, I send a notification from my server.
Is there any way to not display the notification if the app is currently open?
Right now I am using this as soon as the notification is received:
Notifications.dismissNotificationAsync(notification.notificationId);
But there is a 0.5 second delay where the notification has time to appear in the tray and trigger a sound before it gets dismissed. I would like to not show it at all.

When a notification is received while the app is running, using setNotificationHandler you can set a callback that will decide whether the notification should be shown to the user or not.
Notifications.setNotificationHandler({
handleNotification: async () => ({
shouldShowAlert: true,
shouldPlaySound: false,
shouldSetBadge: false,
}),
});
When a notification is received, handleNotification is called with the incoming notification as an argument. The function should respond with a behavior object within 3 seconds, otherwise the notification will be discarded. If the notification is handled successfully, handleSuccess is called with the identifier of the notification, otherwise (or on timeout) handleError will be called.
The default behavior when the handler is not set or does not respond in time is not to show the notification.
If you don't use setNotificaitonHandler, the new notifications will not be displayed while the app is in foreground.
So you can simply set setNotificationHandler to null when your app is initialized.
Notifications.setNotificationHandler(null);
See Documentaition

The answer is yes to your question
Is there any way to not display the notification if the app is
currently open?
The default behavior of Notification in Expo is not to show notification if the App is in foreground. You must have implemented Notifications.setNotificationHandler similar to the following code -
// *** DON'T USE THE FOLLOWING CODE IF YOU DON'T WANT NOTIFICATION TO BE DISPLAYED
// WHILE THE APP IS IN FOREGROUND! ***
// --------------------------------------------------
// Sets the handler function responsible for deciding
// what to do with a notification that is received when the app is in foreground
/*
Notifications.setNotificationHandler({
handleNotification: async () => ({
shouldShowAlert: true,
shouldPlaySound: true,
shouldSetBadge: false,
}),
});
*/
If you don't use setNotificaitonHandler, the new notifications will not be displayed while the app is in foreground.

Use below code snippet. It works on press notification.
_handleNotification = async (notification) => {
const {origin} = notification;
if (origin === ‘selected’) {
this.setState({notification: notification});
}
//OR
if (AppState.currentState !== 'active') {
this.setState({notification: notification});
}
}

I assume you setup a simple FCM - Firebase cloud messaging
And use that to push messages to the client?
The official Expo guide has a section for receiving-push-notifications

This is the actual workflow of FCM (weird can be called as a common issue) that it'll handle the notifications by itself when the application is in the foreground.
The solution which i did for my project was to create a custom notification JSON rather than using their default template which won't be parsed by FCM.
{
"hello":" custom key and value",
"message":{
"SampleKey":"Sample data",
"data":{
"SampleKey" : "Sampledata",
"SampleKey2" : "great match!"},
}}
In console you can add your own custom JSON objects, and when you get the notification parse the notification by using these objects, then you will be able to override that issue.
You can also add a channel for the request to categorize your notifications
this.createNotificationListeners = firebase.notifications()
.onNotification((notification) => {
let{ hello,data,message} = notification;
});

My android app can't receive fcm message from python

I'm building android app with firebase cloud messaging.
My app can receive message from FCM console.
However, it cannot receive from python, although the response is good.
Could you give me some advice?
class fbMessaging():
def __init__(self):
cred = credentials.Certificate('./env/firebase.json')
firebase_admin.initialize_app(cred)
def send_to_device(self, text, token):
message = messaging.Message(
data = {
'title': 'test',
'body': text,
},
token = token,
)
response = messaging.send(message)
return response
def main():
fm = fbMessaging()
res = fm.send_to_device('test', 'MY CORRECT TOKEN')
print(res)
onMessageRecieved is here
override fun onMessageReceived(message: RemoteMessage?) {
val from = message!!.from
val data = message.data
Log.d(TAG, "from:" + from!!)
Log.d(TAG, "data:$data")
}
Printed response is below.
projects/match-XXXXX/messages/0:1554291593xxxxxx%43f99108f9xxxxxx

Using Firebase Cloud Messaging, you can send Notification payload or Data payload or both.
Notification Payload contains
title - Notification Title
body - Notification body
The key names fixed and can't be changed.
Data Payload, on the other hand, is simply a key-value pair and you can send any key name with string type as its value.
FCM Behavior:
Based on whether the app is in the foreground or background and the existence of Notification payload or Data payload or both, the FCM message is received by different components in the app.
Handling of FCM notification as per documentation,
Notification messages delivered when your app is in the background. In this case, the notification is delivered to the device’s system tray. A user tap on a notification opens the app launcher by default.
Messages with both notification and data payload, when received in the background. In this case, the notification is delivered to the device’s system tray, and the data payload is delivered in the extras of the intent of your launcher Activity.
This behavior has been explained clearly in the Receive Messages Section.
As you can see, if only in the case where Notification payload is sent in standalone you don't have to build Notification UI. Otherwise, you have create the Notification UI when onMessageReceived is called.
Using Python:
Notification Payload Example:
message = messaging.Message(
notification=messaging.Notification(
title='This is a Notification Title',
body='This is a Notification Body',
),
token=registration_token,
)
Data Payload Example:
message = messaging.Message(
data={
'score': '850',
'time': '2:45',
},
token=registration_token,
Both:
message = messaging.Message(
notification=messaging.Notification(
title='This is a Notification Title',
body='This is a Notification Body',
),
data={
'score': '850',
'time': '2:45',
},
token=registration_token,

How to collapse multiple notifications into a single one using Firebase?

I have function in Firebase Cloud Functions which is used to send notifications to specific users within my app and has as the notificationContent the following code:
const notificationContent = {
notification: {
title: "My Notification Title",
body: "My Notification Body",
icon: "default",
sound : "default"
}
};
I have tried to use collapse_key: "unique_key" but it has no effect. I read the has an effect only when the device is offline. I also have used a tag: "unique" but every time a new notification arrives, it will override the oldest one.
I there any way in which I can achieve this with Firebase? If I receive more then one notification, to be grouped in a single one?
Thanks in advance!

If you want to use more customizable and advanced notification features.
You should only send FCM with data payload, and create notification at android client side.
Remember that if you send FCM with notification payload or notification + data payload, the notification will be created by android core system and BroadcastReceiver's onReceive method won't being called if your app is on background.
If you send FCM with data payload, it will call onReceive all the time, so you can produce custom notification manually at android client side. (most app uses latter method.)
I hope this link would be helpful.

I had this same confusion and realized I misunderstood what collapseKey and tag are for.
collapseKey will limit the number of notifications a client receives while they're offline, tag is what will stack notifications together in the drawer.
So for a typical cloud function, it should look like this:
const notification = {
notification: {
'title': 'Interesting title',
'body': 'Hello, world'
},
'data': {
'whatever': whatever,
},
'android':{
'collapseKey': collapseKey,
'priority': 'high',
'notification': {
'tag': tag,
}
},
'token': fcmToken
};
admin.messaging().send(notification)
Note that the "tag" parameter sits inside of the android notification, not the top-level notification.

The easiest and most flexible solution is to extend the FirebaseMessagingService and handle the notification yourself. But first instead of using notification on your notificationContent in your cloud function, you have to change that to data so that you send a data message instead of a notification message. The difference is that the notification message will have an implicit collapse key (the package name of the app), while the data message won't have one. But the data message needs to be handled on the client or else it won't be displayed.
Here's a sample of what you'll need for your FirebaseMessagingService:
public class MyFCMService extends FirebaseMessagingService {
#Override
public void onMessageReceived(RemoteMessage remoteMessage) {
if (remoteMessage.getNotification() != null) {
//this notification was sent from the Firebase console, because in our cloud function, we are using the DATA tag, not the notification tag
//so here we have to handle the notification that was sent from the console
...
} else if (remoteMessage.getData().get(KEY) != null) {
//this data message was sent from our cloud function
//KEY is one of the keys that you are using on the cloud function
//in your example, you are using the keys: title, body, icon, sound
//display the notification to the user
...
notificationManager.notify(TAG, ID, notificationBuilder.build());
//you have to use the same TAG and the same ID on each notification if you want your 2nd notification to simply update the text of the first one, instead of showing as a new notification
}
}
}
PS. When you send a notification from your cloud function (well if you use the data tag, it's actually a data message, not a notification message), then this method will be called, regardless if the app is in the background or in the foreground. HOWEVER, when you send a notification from the firebase console, this method will be called ONLY if the app is in the foreground. If the app is in the background, the Firebase SDK will handle the notification and show it to the user. In some cases, it makes sense to show a notification only when the user is not running the app, for example if you want to advertise some new features of the app. In that case, what you can do is use a unique tag on the notification console (e.g. "display_in_foreground") and check that tag on the client. If you have set that to true, you can show the notification even to users that are currently running the app, or if it's false you can choose not to show the notification. This check will happen only if the app is in the foreground. If it's in the background, this won't be called at all and the SDK will handle to show the notification.

Heads up notification using FCM

Do we have any way to show heads up notification, when receive push from Firebase Cloud Messaging? In foreground it is possible using Notification. But there is no way to show heads up notification, when app in background, because onMessageReceived is not calling.
I tried to set priority to "high", but no result.
Do you have any ideas?

After browsing multiple solutions in stackoverflow.com, I found below explanation to be most helpful
How to handle notification when app in background in Firebase
In your Android OnMessageReceived function/method, only Data Payload (RemoteMessage.getData) will trigger your custom notification such as head-up notification when App is in background. Notification Payload (RemoteMessage.getNotification) will not trigger your heads-up notification, and instead default to showing just a tiny icon on your notification tray.
If you're using Firebase Cloud Functions, do check that the information you're sending through is in the data payload, and notification payload should be removed if you want the heads up notification to work. Having notification payload will default to showing just a tiny icon on the notification tray only.
Hope this piece of information helps, and happy coding.

I am using node.js as my server platform. The trick is to remove the 'notification' field and move the 'title' and 'body' fields to 'data'. For my case, I changed:
var message = {
token: targetID,
android:{
priority: 'high'
},
notification: {
title: 'X',
body: req.body.msg
},
data: {
topic: req.body.topic
}
};
to
var message = {
token: targetID,
android:{
priority: 'high'
},
data: {
topic: req.body.topic,
title: 'X',
body: req.body.msg
}
};
then...
fcm.send(message, function(err, response){...

Please follow the below steps..
Now just click next on following two steps with the default setup
This step is very important and this is the main part which will manage the device’s system tray to show as a heads-up notification.
Now click on review and then publish. Let me know if you get the expected result.

Regardless of what platform you are calling firebase, all what you need is to add Title and Body fields to Notification inside Android and of course Priority = High
var aMessage = new Message
{
Topic = "atopic",
Notification = new Notification { Body = body, Title = title },
Data = new Dictionary<string,string> { { "ReferenceId", refId.ToString() } },
Android = new AndroidConfig
{
Priority = Priority.High,
Notification = new AndroidNotification
{
Body = body,
Title = title,
Color = "#ffcc00",
Icon = "ic_notification",
Sound = "default",
ChannelId = "my_notification_channel"
},
},
};

FCM Data Message should be non-collapsibl by default

Based on the documentation, it is my understanding that there are two types of messages that Firebase can send: Notification and Data. Also, they can be either collapsible or non-collapsible with non-collapsible being the default for data messages. This would mean that each message is delivered to the client app. See below:
However, when I send data messages to my client they are collapsed. For example, I send one and it appears in the notification bar with no problem but if I don't open it and another message comes in, it is replaced by the new message. Here's some of my code.
Data message:
//create the notification payload
let payload = {
data: {
title: 'Title',
context: context,
parent: parent,
body: user + " commented on your contribution.",
sound: 'default'
}
};
//send the notification
return admin.messaging().sendToDevice(userToken, payload).then(ok =>{
console.log('Notification sent to: ' + submitter);
}).catch(error => {
console.log('Could not send notification.');
});
What am I doing wrong? I want each notification to appear and not be replaced.

You are debugging at the wrong end. The actual problem is on the client side where you are posting the notification.
While posting the notification if the notification id is the same Android OS will replace the existing notification.
Look for the notify() in your code. Refer to this doc for more details : https://developer.android.com/reference/android/app/NotificationManager.html#notify(int, android.app.Notification)