Email notifications in firebase

Question

I would like to know if anyone knows a way where you can send an email when a specific node in firebase is created, updated or deleted?

More specifically, I have a web service where users can book each other for a period of time. I use Firebase as the backend to store user information and so on but I want to send a confirmation to the users' email address whenever a booking has occurred. I understand that this has previously been possible using Zapier, however they no longer support Firebase.

Anyone who has a workaround or an idea on how to send email notifications in Firebase?

Answer 1

After searching some more I found that there is no direct plugin. I contacted the firebase support team and they are considering to create this functionality themselves; however, when and how is not yet decided.
There are different possibilities but they all require some kind of back end coding, meaning a server that can watch for these changes.
I landed on node.js as this is most similar to what I usually work on, i.e. javascript.
By including nodemailer and firebase through npm, sending emails based on firebase event was achieved like this:

var firebase = require("firebase");

var mainApp = firebase.initializeApp({
    //firebase authentication
});

var directTransport = require('nodemailer-direct-transport');
var nodemailer = require('nodemailer');
var options = {};
var transporter = nodemailer.createTransport(directTransport(options))

var nodemailer = require('nodemailer');

var transporter = nodemailer.createTransport({
    service: 'gmail',
    auth: {
        user: 'example.gmail.com'
        pass: 'password'
    }
});

var nodeToWatch = mainApp.database().ref('node_to_watch'); //firebase node to watch

nodeToWatch.on('child_added', function(childSnapshot) { //fires once for every node in this location
    if(!childSnapshot.val().email_sent){ //check if email has already been sent

            nodeToWatch.child(childSnapshot.key).child('email_sent').set(firebase.database.ServerValue.TIMESTAMP).then(function(response){ //set email value to sent

                var data = JSON.stringify(childSnapshot.val(), null, 9); //stringify the response so we can attach it in the email

                // create template based sender function
                var sendInfo = transporter.templateSender({
                    subject: 'Node in firebase updated',
                    html: 'Hello, data for new node is: {{data}}
                }, {
                from: 'example.gmail.com'
                });

                // use template based sender to send a message
                sendInfo({
                    to: 'exampleRecipient.email.com'
                }, {
                    data: data //data variable to insert into email
                }, function(err, info){
                    if(err){
                        console.log(err);
                    }
                    else{
                        console.log('Email sent');
                    }
                });
            });

    }

});

This example listens for the firebase on_child_added event but any firebase event will work. Hope this helps someone! :)