passport-google-oauth20

Passport strategy for authenticating with Google using OAuth 2.0.

This module lets you authenticate using Google in your Node.js applications. By plugging into Passport, Google authentication can be easily and unobtrusively integrated into any application or framework that supports Connect-style middleware, including Express.

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Install

$ npm install passport-google-oauth20

TypeScript support

$ npm install @types/passport-google-oauth20

Usage

Register Application

The Google strategy authenticates users using their Google account. Before your application can make use of Google's authentication system, you must first register your app to use OAuth 2.0 with Google APIs. Once registered, a client ID and secret will be issued which are used by Google to identify your app. To register, complete the following steps:

1. Go to the Google Cloud Platform console.

2. From the projects list, select a project or create a new one.

3. Navigate to the APIs & Services page and select Credentials.

4. If you have an existing application, it will be listed under OAuth 2.0 Client IDs. Click Edit OAuth client to obtain the client ID and secret, and proceed to configure the strategy. Otherwise, continue.

5. If you have not already done so, configure the OAuth consent screen. Select External to make your application available to any user with a Google account. Complete the app registration process by entering the app name, support email, and developer contact information.

6. Click Create Credentials, then select OAuth client ID.

7. Select Web application as Application type.

8. Click Add URI under Authorized Redirect URIs. Enter the URL of your application's OAuth 2.0 redirect endpoint. If you are using the example app, enter http://localhost:3000/oauth2/redirect/accounts.google.com.

9. Click Create to create the OAuth client. The following screen will display your client ID and secret. Proceed to configure the strategy.

Configure Strategy

The Google authentication strategy authenticates users using a Google account and OAuth 2.0 tokens. The client ID and secret obtained when creating an application are supplied as options when creating the strategy. The strategy also requires a verify callback, which receives the access token and optional refresh token, as well as profile which contains the authenticated user's Google profile. The verify callback must call cb providing a user to complete authentication.

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

passport.use(new GoogleStrategy({
    clientID: GOOGLE_CLIENT_ID,
    clientSecret: GOOGLE_CLIENT_SECRET,
    callbackURL: "http://www.example.com/auth/google/callback"
  },
  function(accessToken, refreshToken, profile, cb) {
    User.findOrCreate({ googleId: profile.id }, function (err, user) {
      return cb(err, user);
    });
  }
));

Define Routes

Two routes are needed in order to allow users to log in with their Google account. The first route redirects the user to the Google, where they will authenticate:

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

The second route processes the authentication response and logs the user in, after Google redirects the user back to the app:

app.get('/oauth2/redirect/accounts.google.com',
  passport.authenticate('google', { failureRedirect: '/login', failureMessage: true }),
  function(req, res) {
    res.redirect('/');
  });

Examples

• express-4.x-google-oauth2-example

  Illustrates how to use the Google strategy within an Express application.

License

The MIT License

Copyright (c) 2012-2021 Jared Hanson <http://jaredhanson.net/>