How to build a public Google Workspace Admin integration: Building the Auth Flow

Aug 3, 2024 • 7 minute read

Hey there, fellow JavaScript devs! Ready to dive into the world of Google Workspace Admin integrations? Let's focus on the most crucial part: building a rock-solid auth flow. Buckle up, because we're about to make your integration secure and user-friendly in no time.

Prerequisites

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

A Google Cloud Console project (you've got this, right?)
Necessary APIs enabled (you know the drill)
OAuth 2.0 client credentials (your golden ticket)

Choosing the Right OAuth 2.0 Flow

For server-side apps, the Authorization Code flow is your best friend. If you're building a client-side app, you might be tempted by the Implicit flow, but trust me, it's better to avoid it. Stick with the Authorization Code flow – it's more secure and flexible.

Implementing the Authorization Code Flow

Let's break this down into manageable steps:

Constructing the Authorization URL

const authUrl = 'https://accounts.google.com/o/oauth2/v2/auth';
const params = new URLSearchParams({
  client_id: YOUR_CLIENT_ID,
  redirect_uri: YOUR_REDIRECT_URI,
  response_type: 'code',
  scope: 'https://www.googleapis.com/auth/admin.directory.user.readonly',
  access_type: 'offline',
  prompt: 'consent'
});

const fullAuthUrl = `${authUrl}?${params.toString()}`;

Handling the Redirect and Extracting the Auth Code

app.get('/oauth2callback', (req, res) => {
  const authCode = req.query.code;
  // Use this authCode to get tokens
});

Exchanging the Auth Code for Tokens

const tokenUrl = 'https://oauth2.googleapis.com/token';
const response = await fetch(tokenUrl, {
  method: 'POST',
  headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
  body: new URLSearchParams({
    code: authCode,
    client_id: YOUR_CLIENT_ID,
    client_secret: YOUR_CLIENT_SECRET,
    redirect_uri: YOUR_REDIRECT_URI,
    grant_type: 'authorization_code'
  })
});

const { access_token, refresh_token } = await response.json();

Storing Tokens Securely

Please, for the love of all that is holy in the coding world, store these tokens securely. Use encryption, secure storage solutions, or a trusted secret management service. Your future self will thank you.

Token Management

Tokens don't last forever, so let's keep them fresh:

async function refreshAccessToken(refresh_token) {
  const response = await fetch('https://oauth2.googleapis.com/token', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      refresh_token,
      client_id: YOUR_CLIENT_ID,
      client_secret: YOUR_CLIENT_SECRET,
      grant_type: 'refresh_token'
    })
  });

  const { access_token } = await response.json();
  return access_token;
}

Scopes and Permissions

Be a good citizen of the API world – only ask for what you need. Start with the minimum scopes and use incremental authorization if you need more later. Your users will appreciate your restraint.

Making Authenticated API Requests

Now that you've got your shiny access token, put it to work:

const response = await fetch('https://admin.googleapis.com/admin/directory/v1/users', {
  headers: {
    Authorization: `Bearer ${access_token}`
  }
});

if (!response.ok) {
  // Handle API errors here
}

const data = await response.json();

Security Considerations

Security isn't just a feature, it's a lifestyle. Here are some tips to keep your integration Fort Knox-level secure:

Use the state parameter to prevent CSRF attacks
Implement PKCE (Proof Key for Code Exchange) for added security
Always validate tokens before use

Testing and Debugging

When things go sideways (and they will), the OAuth 2.0 Playground is your best friend. It's like a sandbox for auth flows – play around, break things, and learn without fear.

Conclusion

And there you have it! You've just built a secure, user-friendly auth flow for your Google Workspace Admin integration. Pat yourself on the back – you've taken a big step towards creating a killer app.

Remember, the auth flow is the foundation of your integration. Get this right, and you're well on your way to building something awesome. Keep exploring, keep learning, and most importantly, keep coding!

Additional Resources

Want to dive deeper? Check out these goldmines of information:

Now go forth and integrate with confidence! You've got this. 💪