unleash.unleash/docs/guides/google-auth-hook.md

id	title
google_auth	Google Auth Hook

This part of the tutorial shows how to create a sign-in flow for users and integrate with Unleash server project. The implementation assumes that I am working in localhost with 4242 port.

This is a simple index.js server file.

const unleash = require('unleash-server');

unleash.start(options).then(unleash => {
  console.log(`Unleash started on http://localhost:${unleash.app.get('port')}`);
});

Creating a web application client ID

1. Go to the credentials section in the Google Cloud Platform Console.

2. Click OAuth consent screen. Type a product name. Fill in any relevant optional fields. Click Save.

3. Click Create credentials > OAuth client ID.

4. Under Application type, select Web Application.

5. Type the Name.

6. Under Authorized redirect URIs enter the following URLs, one at a time.

http://localhost:4242/api/auth/callback

7. Click Create.

8. Copy the CLIENT ID and CLIENT SECRET and save them for later use.

Add dependencies

Add two dependencies @passport-next/passport and @passport-next/passport-google-oauth2 inside index.js file

const unleash = require('unleash-server');
const passport = require('@passport-next/passport');
const GoogleOAuth2Strategy = require('@passport-next/passport-google-oauth2')
  .Strategy;

Configure the Google strategy for use by Passport.js

OAuth 2-based strategies require a verify function which receives the credential (accessToken) for accessing the Google API on the user's behalf, along with the user's profile. The function must invoke cb with a user object, which will be set at req.user in route handlers after authentication.

const GOOGLE_CLIENT_ID = '...';
const GOOGLE_CLIENT_SECRET = '...';
const GOOGLE_CALLBACK_URL = 'http://localhost:4242/api/auth/callback';

passport.use(
  new GoogleOAuth2Strategy(
    {
      clientID: GOOGLE_CLIENT_ID,
      clientSecret: GOOGLE_CLIENT_SECRET,
      callbackURL: GOOGLE_CALLBACK_URL,
    },
    function(accessToken, refreshToken, profile, cb) {
      // Extract the minimal profile information we need from the profile object
      // and connect with Unleash to get name and email.
      cb(
        null,
        new unleash.User({
          name: profile.displayName,
          email: profile.emails[0].value,
        }),
      );
    },
  ),
);

Add googleAdminAuth() function and other options

function googleAdminAuth(app) {}

let options = {
  enableLegacyRoutes: false,
  adminAuthentication: 'custom',
  preRouterHook: googleAdminAuth,
};

unleash.start(options).then(instance => {
  console.log(
    `Unleash started on http://localhost:${instance.app.get('port')}`,
  );
});

In googleAdminAuth function

Configure passport package.

function googleAdminAuth(app) {
  app.use(passport.initialize());
  app.use(passport.session());
  passport.serializeUser((user, done) => done(null, user));
  passport.deserializeUser((user, done) => done(null, user));
  // ...
}

Implement a preRouter hook for /api/admin/login. It's neccesary for login with Google.

function googleAdminAuth(app) {
  // ...
  app.get(
    '/api/admin/login',
    passport.authenticate('google', { scope: ['email'] }),
  );
  // ...
}

Implement a preRouter hook for /api/auth/callback. It's a callback when the login is executed.

function googleAdminAuth(app) {
  // ...
  app.get(
    '/api/auth/callback',
    passport.authenticate('google', {
      failureRedirect: '/api/admin/error-login',
    }),
    (req, res) => {
      // Successful authentication, redirect to your app.
      res.redirect('/');
    },
  );
  // ...
}

Implement a preRouter hook for /api/admin.

function googleAdminAuth(app) {
  // ...
  app.use('/api/admin/', (req, res, next) => {
    if (req.user) {
      next();
    } else {
      // Instruct unleash-frontend to pop-up auth dialog
      return res
        .status('401')
        .json(
          new unleash.AuthenticationRequired({
            path: '/api/admin/login',
            type: 'custom',
            message: `You have to identify yourself in order to use Unleash. Click the button and follow the instructions.`,
          }),
        )
        .end();
    }
  });
  // ...
}

The complete code

The index.js server file.

'use strict';

const unleash = require('unleash-server');
const passport = require('@passport-next/passport');
const GoogleOAuth2Strategy = require('@passport-next/passport-google-oauth2');

const GOOGLE_CLIENT_ID = '...';
const GOOGLE_CLIENT_SECRET = '...';
const GOOGLE_CALLBACK_URL = 'http://localhost:4242/api/auth/callback';

passport.use(
  new GoogleOAuth2Strategy(
    {
      clientID: GOOGLE_CLIENT_ID,
      clientSecret: GOOGLE_CLIENT_SECRET,
      callbackURL: GOOGLE_CALLBACK_URL,
    },
    (accessToken, refreshToken, profile, cb) => {
      cb(
        null,
        new unleash.User({
          name: profile.displayName,
          email: profile.emails[0].value,
        }),
      );
    },
  ),
);

function googleAdminAuth(app) {
  app.use(passport.initialize());
  app.use(passport.session());
  passport.serializeUser((user, done) => done(null, user));
  passport.deserializeUser((user, done) => done(null, user));

  app.get(
    '/api/admin/login',
    passport.authenticate('google', { scope: ['email'] }),
  );
  app.get(
    '/api/auth/callback',
    passport.authenticate('google', {
      failureRedirect: '/api/admin/error-login',
    }),
    (req, res) => {
      res.redirect('/');
    },
  );

  app.use('/api/admin/', (req, res, next) => {
    if (req.user) {
      next();
    } else {
      return res
        .status('401')
        .json(
          new unleash.AuthenticationRequired({
            path: '/api/admin/login',
            type: 'custom',
            message: `You have to identify yourself in order to use Unleash. Click the button and follow the instructions.`,
          }),
        )
        .end();
    }
  });
}

const options = {
  enableLegacyRoutes: false,
  adminAuthentication: 'custom',
  preRouterHook: googleAdminAuth,
};

unleash.start(options).then(instance => {
  console.log(
    `Unleash started on http://localhost:${instance.app.get('port')}`,
  );
});