How to build a public OneLogin integration: Building the Auth Flow

Introduction

Hey there, fellow JavaScript enthusiast! Ready to dive into the world of OneLogin integration? You're in for a treat. We're going to walk through building a slick auth flow for a user-facing integration that'll make your app shine. OneLogin is a powerhouse for identity management, and by the end of this guide, you'll have a robust integration up and running.

Prerequisites

Before we jump in, make sure you've got:

• A OneLogin developer account (if you don't have one, go grab it!)
• A solid grasp on OAuth 2.0 (you're a pro, right?)
• Node.js and Express.js set up and ready to roll

Setting up the OneLogin Application

First things first, let's get our OneLogin app set up:

1. Head over to the OneLogin developer portal and create a new app.
2. Configure your redirect URIs - this is where OneLogin will send your users after authentication.
3. Set up your scopes - these determine what info you can access about your users.

Implementing the Authorization Flow

Initiating the auth request

Time to kick off the auth process:

const authUrl = `https://your-subdomain.onelogin.com/oidc/2/auth?client_id=${clientId}&redirect_uri=${redirectUri}&response_type=code&scope=${scopes}`;
res.redirect(authUrl);

This will send your user to OneLogin's login page. Pretty neat, huh?

Handling the callback

Once the user authenticates, OneLogin will redirect them back to you with an authorization code. Let's exchange that for some tokens:

app.get('/callback', async (req, res) => {
  const { code } = req.query;
  const tokenResponse = await axios.post('https://your-subdomain.onelogin.com/oidc/2/token', {
    grant_type: 'authorization_code',
    code,
    redirect_uri: redirectUri,
    client_id: clientId,
    client_secret: clientSecret
  });

  const { access_token, refresh_token } = tokenResponse.data;
  // Store these tokens securely!
});

Making API Requests

Now that you've got your access token, you can start making API requests:

const userInfo = await axios.get('https://your-subdomain.onelogin.com/oidc/2/me', {
  headers: { Authorization: `Bearer ${access_token}` }
});

Remember to handle token expiration and refresh when needed!

Implementing Logout

Don't forget to give your users a way out:

app.get('/logout', async (req, res) => {
  await axios.post('https://your-subdomain.onelogin.com/oidc/2/token/revocation', {
    token: refresh_token,
    client_id: clientId,
    client_secret: clientSecret
  });
  // Clear your local session here
});

Error Handling and Edge Cases

Always be prepared for the unexpected:

• Invalid tokens? Refresh or re-authenticate.
• User cancelled? Handle it gracefully.
• Network issues? Retry with exponential backoff.

Security Considerations

Security is key, so don't skimp on these:

• Always use HTTPS
• Implement CSRF protection
• Store tokens securely (not in local storage!)

Testing the Integration

Before you pop the champagne, make sure to thoroughly test your integration:

1. Try logging in with different user types
2. Test token refresh scenarios
3. Attempt to access resources after logout

Consider setting up some automated tests to catch any regressions.

Conclusion

And there you have it! You've just built a rock-solid OneLogin integration. Your users can now enjoy seamless authentication, and you can rest easy knowing you've implemented it securely.

Remember, this is just the beginning. You can expand on this integration to add more features, like role-based access control or multi-factor authentication. The sky's the limit!

Now go forth and authenticate with confidence! 🚀