Implementing Google OAuth Using Passport in Node.js

Passport is a popular authentication middleware for Node.js that supports many authentication methods, including Google OAuth. In this article, we will walk through the steps to implement Google OAuth using Passport in a Node.js application.

Step 1: Set Up a New Node.js Project

The first step is to set up a new Node.js project. Open your terminal and run the following commands:

mkdir passport-google
cd passport-google
npm init -y

This will create a new directory called passport-google and initialize a new Node.js project in it.

Step 2: Install Dependencies

Next, we need to install the necessary dependencies for Passport and Google OAuth. Run the following command:

npm install passport passport-google-oauth20

This will install Passport and the Passport Google OAuth 2.0 authentication strategy.

Step 3: Configure Google OAuth Credentials

Go to the Google Cloud Console and create a new project. Then, go to the "APIs & Services" > "Credentials" page and click on "Create Credentials" > "OAuth client ID". Choose "Web application" as the application type and enter the following details:

Name: Any name you want to give to the OAuth client ID.
Authorized JavaScript origins: http://localhost:3000
Authorized redirect URIs: http://localhost:3000/auth/google/callback

Click on "Create" and note down the client ID and client secret.

Step 4: Configure Passport

Create a new file called index.js in your project directory and add the following code:

javascript

const express = require('express');
const passport = require('passport');
const GoogleStrategy = require('passport-google-oauth20').Strategy;

const app = express();

passport.use(new GoogleStrategy({
    clientID: 'YOUR_CLIENT_ID',
    clientSecret: 'YOUR_CLIENT_SECRET',
    callbackURL: 'http://localhost:3000/auth/google/callback'
  },
  (accessToken, refreshToken, profile, done) => {
    // Callback function
    console.log(profile);
  }
));

app.get('/auth/google', passport.authenticate('google', { scope: ['profile', 'email'] }));

app.get('/auth/google/callback', passport.authenticate('google'));

app.listen(3000, () => {
  console.log('Server started on port 3000');
});

Replace YOUR_CLIENT_ID and YOUR_CLIENT_SECRET with the client ID and client secret you obtained in Step 3.

This code configures Passport to use the Google OAuth 2.0 authentication strategy. When a user visits the /auth/google route, Passport will redirect them to the Google OAuth consent screen. If the user grants permission to the application, they will be redirected back to the /auth/google/callback route with an access token. Passport will then use this access token to fetch the user's profile information and call the callback function specified in the GoogleStrategy constructor.

Step 5: Test the Application

Start the server by running node index.js in your terminal. Open your web browser and go to http://localhost:3000/auth/google. You should be redirected to the Google OAuth consent screen. Grant permission to the application and you should be redirected back to http://localhost:3000/auth/google/callback. Check your terminal output for the user's profile information.

In conclusion, using Passport to implement Google OAuth in Node.js is a simple and effective way to authenticate users in your web application. By following these steps, you can easily implement Google OAuth using Passport in your Node.js project.

Implementing Google OAuth Using Passport in Node.js ​

Step 1: Set Up a New Node.js Project ​

Step 2: Install Dependencies ​

Step 3: Configure Google OAuth Credentials ​