Firebase push notifications - node worker

Question

I need to send iOS push notifications to user whenever a certain child is added to a Firebase path.

I was thinking, that the best way to do that, would be to make a Node.js worker on Heroku, that would listen for changes and send a notification using Urban Airship.

I'm not sure what the best way is to listen for changes on Firebase from a Node.js worker on Heroku is. I'm not that familiar with heroku workers and Node.js.

Can anyone give me some pointers? Examples?

Answer 1

Sending push notifications with Firebase and node-apn is easy:

var apn = require("apn");
var Firebase = require("firebase");

// true for production pipeline
var service = new apn.connection({ production: false }); 

// Create a reference to the push notification queue
var pushRef = new Firebase("<your-firebase>.firebaseio.com/notificationQueue");
// listen for items added to the queue
pushRef.on("child_added", function(snapshot) {

    // This location expects a JSON object of:
    // {
    //     "token": String - A user's device token
    //     "message": String - The message to send to the user
    // }
    var notificationData = snapshot.val();
    sendNotification(notificationData);
    snapshot.ref().remove();

});

function sendNotification(notificationData) {
    var notification = new apn.notification();
    // The default ping sound
    notification.sound = "ping.aiff";
    // Your custom message
    notification.alert = notificationData.message;
    // Send the notification to the specific device token
    service.pushNotification(notification, [notificationData.token]);
    // Clean up the connection
    service.shutdown();
}

For hosting this script, you won't be able to use a PaaS like Heroku. They tend to kill idle sockets. Instead you'll have to use a virtual machine.

Google Cloud Platform has a Node.js launcher that works well.