CODEWITHSUNDEEP
javascriptfirebasefirebase-cloud-messaginggoogle-cloud-functions
Richard Ansell
Richard Ansell

Reputation: 926

Send FCM to all Android devices using Cloud Functions

Just trying to understand the process for sending a Firebase Cloud Message using Cloud Functions to notify all users who have my app installed on their phone. This would fire whenever a new event has been added at a particular branch, as follows:

var functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);

const payload = {
  notification: {
    title: 'New event added'
  }
};

exports.bookingsChanged = functions.database.ref("/Events")
  .onWrite(event => {
    return admin.messaging().sendToDeviceGroup("latest_events", payload);
  });

The above function I've uploaded doesn't appear to send the message to the Android device I'm using at all, despite setting up and testing FCM using the Firebase Console option to send messages. I've noticed there is little documentation for this at the moment, so any help would be greatly appreciated!

EDIT

I may've missed this, but I've replaced the string 'latest_events' with my Android application package name that I assume is required, as per the console to target a 'User Segment'.

Upvotes: 1

Views: 1259

Answers (1)

Richard Ansell
Richard Ansell

Reputation: 926

Ended up solving this by waiting for a topic I had set up to appear in the Firebase Notifications dashboard. I then changed the following code to send to this topic directly:

return admin.messaging().sendToTopic("latest_events", payload);

I also found out that you have to provide a token when using 'sendToDevicegroup' after coming across the API documentation. Therefore, topics are more effective in my use case as I do not wish to obtain tokens to send to specific user devices.

Hope this helps someone who experiences a similar problem!

ADDITIONAL EDIT

If like me, you would like to alert users only of new events that have been added to a specific branch, typically including a push id, I've created the following code to implement this.

With a little help from the examples in the documentation, this will evaluate the number of records at the location compared to the previous location. Thus, this will only alert users of new child records that are added, rather than every time a record is edited and deleted.

var functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);

exports.bookingsChanged = functions.database.ref("/Bookings").onWrite(event 
    => {

    var payload = {
        notification: {
            title: "A new event has been added!"
        }
    };

    if (event.data.previous.exists()) {
        if (event.data.previous.numChildren() < event.data.numChildren()) {
            return admin.messaging().sendToTopic("latest_events", payload);
        } else {
            return;
        }
    }

    if (!event.data.exists()) {
        return;
    }

    return admin.messaging().sendToTopic("latest_events", payload);

});

Upvotes: 1

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