Write event webhook

Now let's move to the second use-case of sending an email when a user registers on the app.

When the user registers on the app using Auth0, we insert a new row into the users table to keep the user data in sync. Remember the Auth0 rule we wrote during signup to make a mutation?

This is an insert operation on table users. The payload for each event is mentioned here

Now we are going to capture this insert operation to trigger our event.

SendGrid SMTP Email API

For this example, we are going to make use of SendGrid's SMTP server and use nodemailer to send the email.

Signup on SendGrid and create a free account.

Create an API Key by following the docs here

Write the webhook

const nodemailer = require('nodemailer');
const transporter = nodemailer.createTransport('smtp://'+process.env.SMTP_LOGIN+':'+process.env.SMTP_PASSWORD+'@' + process.env.SMTP_HOST);
const fs = require('fs');
const path = require('path');
const express = require('express');
const bodyParser = require('body-parser');
const app = express();

app.set('port', (process.env.PORT || 3000));

app.use('/', express.static(path.join(__dirname, 'public')));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));

app.use(function(req, res, next) {
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Cache-Control', 'no-cache');
    next();
});

app.post('/send-email', function(req, res) {
  
  const name = req.body.event.data.new.name;
  // setup e-mail data
  const mailOptions = {
      from: process.env.SENDER_ADDRESS, // sender address
      to: process.env.RECEIVER_ADDRESS, // list of receivers
      subject: 'A new user has registered', // Subject line
      text: 'Hi, This is to notify that a new user has registered under the name of ' + name, // plaintext body
      html: '<p>'+'Hi, This is to notify that a new user has registered under the name of ' + name + '</p>' // html body
  };
  // send mail with defined transport object
  transporter.sendMail(mailOptions, function(error, info){
      if(error){
          return console.log(error);
      }
      console.log('Message sent: ' + info.response);
      res.json({'success': true});
  });
  
});

app.listen(app.get('port'), function() {
  console.log('Server started on: ' + app.get('port'));
});