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

Hey there, fellow JavaScript enthusiast! Ready to dive into the world of Bigin integrations? Today, we're going to tackle one of the most crucial parts of building a public integration: the authorization flow. Don't worry, it's not as daunting as it sounds. By the end of this article, you'll be auth-flow-savvy and ready to take on the world (or at least the Bigin API).

Prerequisites

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

• Node.js and npm installed (you're a JS dev, so I'm sure you've got this)
• A Bigin developer account (if you don't have one, go grab it!)
• Your favorite code editor (VS Code, anyone?)

Setting up the project

Let's get this party started! Open up your terminal and run:

mkdir bigin-integration && cd bigin-integration
npm init -y
npm install express axios dotenv

Great! Now you've got a basic project setup with Express for our server, Axios for making HTTP requests, and dotenv for managing environment variables.

Understanding Bigin's OAuth 2.0 flow

Bigin uses OAuth 2.0 for authorization. It's like a fancy handshake between your app and Bigin. Here's the gist:

1. Your app asks the user to authorize it.
2. User logs in to Bigin and grants permission.
3. Bigin sends back an authorization code.
4. Your app exchanges this code for an access token.
5. You use this token to make API requests. Simple, right?

Implementing the auth flow

Initiating the auth request

First, let's create a route that'll start the auth process:

require('dotenv').config();
const express = require('express');
const app = express();

app.get('/auth', (req, res) => {
  const authUrl = `https://accounts.zoho.com/oauth/v2/auth?scope=ZohoBigin.settings.ALL&client_id=${process.env.CLIENT_ID}&response_type=code&redirect_uri=${encodeURIComponent(process.env.REDIRECT_URI)}`;
  res.redirect(authUrl);
});

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

When a user hits this route, they'll be whisked away to Bigin's login page. Magic!

Handling the callback

Now, let's set up a route to handle Bigin's callback:

const axios = require('axios');

app.get('/callback', async (req, res) => {
  const { code } = req.query;
  
  try {
    const response = await axios.post('https://accounts.zoho.com/oauth/v2/token', null, {
      params: {
        code,
        client_id: process.env.CLIENT_ID,
        client_secret: process.env.CLIENT_SECRET,
        redirect_uri: process.env.REDIRECT_URI,
        grant_type: 'authorization_code'
      }
    });

    const { access_token, refresh_token } = response.data;
    // Store these tokens securely!
    
    res.send('Authorization successful!');
  } catch (error) {
    console.error('Error exchanging code for token:', error);
    res.status(500).send('Authorization failed');
  }
});

This code exchanges the authorization code for an access token. Remember to store these tokens securely!

Refreshing the access token

Access tokens don't last forever. Here's how to refresh them:

async function refreshAccessToken(refreshToken) {
  try {
    const response = await axios.post('https://accounts.zoho.com/oauth/v2/token', null, {
      params: {
        refresh_token: refreshToken,
        client_id: process.env.CLIENT_ID,
        client_secret: process.env.CLIENT_SECRET,
        grant_type: 'refresh_token'
      }
    });

    return response.data.access_token;
  } catch (error) {
    console.error('Error refreshing token:', error);
    throw error;
  }
}

Error handling and edge cases

Always expect the unexpected! Here's a simple error handler:

app.use((err, req, res, next) => {
  console.error(err.stack);
  res.status(500).send('Something broke!');
});

Testing the auth flow

Time to put on your tester hat! Start your server and navigate to http://localhost:3000/auth. If everything's set up correctly, you should be able to authorize your app and see the "Authorization successful!" message.

Best practices and security considerations

1. Never, ever, ever store your client secret in your code. Use environment variables!
2. Always use HTTPS in production.
3. Consider implementing PKCE for added security.

Conclusion

And there you have it! You've just built a robust auth flow for your Bigin integration. Pat yourself on the back – you've earned it!

Remember, this is just the beginning. With this auth flow in place, you're now ready to start making API calls and building out the rest of your integration. The world is your oyster!

Additional resources

• Bigin API Documentation
• OAuth 2.0 Simplified

Now go forth and integrate! And remember, if you get stuck, the developer community is always here to help. Happy coding!