Send email using OAuth2, NodeJs the right way

Hello there, I wrote an article few months ago about how to send email with NodeJs. Check the article here.

While the method described in the blog works well, there are several drawbacks to using it.
Today, I'll walk you through a better way to send email in NodeJs.

Prerequisite

🎯 Install NodeJS
🎯 NodeJS RestAPI fundamentals

Setup

Head on google developer console and create a new project and add a project name and click create

Switch to the project you just created. I named mine Luther.

Creating API credentials, click on the hamburger menu and navigate to API and Services

Let's get our credentials

Click on credentials

Click on OAuth ClientId

Click on configure consent screen

Click on create

Configure the screen

Add your app name, email and logo in the highlighted box

Click Save and continue

Click on save and continue while leaving all other settings as default

Click the create credentials icon again

Click Oauth CLient Id

Choose an application type

Add your redirect and click the create button

You will get your clientID and secret, you can download or copy to somewhere safe

Configure OAuth

Go to this url https://developers.google.com/oauthplayground and click on the gear icon

Click use own credentials

Enter the clientID and the secret key you saved earlier

Next enter this url: https://mail.google.com/ in highlighted box in orange below

Click on the authorized api button and choose the email you want to authorize Fig X

Fixing error -> Sometimes you get authorization error at this point

To fix let's authorize our app, go to dashboard and click the OAuth consent screen

Click on publish

Retry the Fig X process and yo get the directed to this page

Click on the Advanced button, then the unsafe button

Click on continue

You should get redirected back to the OAuth page

Click on exchange authorization code for token in the Step 2 secttion

This will generate refresh token, access token and Authorization code. Copy and save it somewhere safe.

Now that we have gotten api google console credentials, let's create our NodeJS app using ExpressJS

Intialize a NodeJs app

npm init -y

Install Development Dependencies

npm i express nodemailer googleapis

Create a NodeJS Server

index.js

Create a user model

models/user.model.js

Create a user route

routes/user.route.js

const router = express.Router();

// signup
router.post('/signup', userSignup);
//...
modeule.exports = router;

Create your nodejs app and create a mail folder inside

const nodemailer = require('nodemailer');
const { google } = require('googleapis');
const OAuth2 = google.auth.OAuth2;

const oauth2Client = new OAuth2(
  'put client id here',
  'put client secret here', // Client Secret
  'https://developers.google.com/oauthplayground' // Redirect URL
);

oauth2Client.setCredentials({
  refresh_token:
    ' add your refresh token here',
});
const accessToken = oauth2Client.getAccessToken();

const sendEmail = async (options) => {
  const transporter = nodemailer.createTransport({
    service: 'gmail',
    auth: {
      type: 'OAuth2',
      user: 'put your email here',
      clientId:
        'put your client id here',
      clientSecret: 'put your client secret here',
      refreshToken:
        'put your refresh token here',
      accessToken: accessToken,
    },
    tls: {
      rejectUnauthorized: false,
    },
  });
  try {
    const message = {
      from: "put your email here",
      to: options.email,
      subject: options.subject,
      text: options.message,
      html: options.message,
    };

    const m = await transporter.sendMail(message);
    console.log(m);
  } catch (error) {
    console.log(error);
    return error;
  }
};

module.exports = sendEmail;

Then in your user.controller.js file

const User = require('../models/user.model');
const House = require('../models/house.model');
const bcrypt = require('bcrypt');
const jwt = require('jsonwebtoken');
const sendEmail = require('../mail/email-sender');

exports.userSignup = async (req, res) => {
  const { password, email, name } = req.body;
  try {
    //  hash password
    const salt = await bcrypt.genSalt(10);
    const hashedPassword = await bcrypt.hash(password, salt);
    const user = await User.create({
      name,
      email,
      password: hashedPassword,
    });
    await sendEmail({
      email: user.email,
      subject: `${user.name} Registered Successfully`,
      message: `<div>
          <h1>HELLO ${user.name}</h1>
          <h2>You just registered successfully</h2>
      </div>`,
    });
    return res
      .status(201)
      .json({ message: 'User created successfully', userId: user._id });
  } catch (error) {
    console.log(error);
    if (error.message.includes('duplicate key error')) {
      return res
        .status(200)
        .json({ message: `${error.message.split('{')[1]} already exist` });
    }
    return res
      .status(500)
      .json({ error: error.message, message: 'internal server error' });
  }
};

⚠️: Ensure you use your .env to store your credentials

Testing our API

Let's test our API using postman

Check Integrated terminal for output

Check email

🕺🏻🕺🏻🕺🏻🕺🏻🕺🏻 It worked

Conclusion

I hope this post was helpful in sending email using NodeJS.
Thanks for reading