How to build a public Basecamp 3 integration: Building the Auth Flow

Hey there, fellow developer! Ready to dive into the world of Basecamp 3 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, and I'll be here to guide you through every step.

Introduction

Basecamp 3's API is a powerful tool that allows us to create some pretty awesome integrations. But before we can start playing with all the cool features, we need to make sure we're doing things by the book. That means implementing a rock-solid authorization flow. Trust me, getting this right from the get-go will save you a ton of headaches down the road.

Prerequisites

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

• A Basecamp 3 account (duh!)
• A registered OAuth application (you can set this up in your Basecamp account)
• A Node.js environment ready to go

Got all that? Great! Let's get started.

OAuth 2.0 Flow Overview

We'll be using the Authorization Code Grant type of OAuth 2.0. It's like a secret handshake between your app and Basecamp. You'll need three key pieces of information:

1. Client ID
2. Client Secret
3. Redirect URI

Keep these safe – they're the keys to your kingdom!

Implementing the Authorization Flow

Initiating the Authorization Request

First things first, we need to send our user to Basecamp's authorization page. Here's how we do it:

const authUrl = `https://launchpad.37signals.com/authorization/new?type=web_server&client_id=${clientId}&redirect_uri=${redirectUri}`;
res.redirect(authUrl);

This will redirect your user to Basecamp's authorization page. They'll log in and grant your app permission.

Handling the Callback

Once the user grants permission, Basecamp will redirect them back to your redirect_uri with an authorization code. Let's grab that code:

app.get('/callback', (req, res) => {
  const authCode = req.query.code;
  // Now we can use this code to get an access token
});

Exchanging the Code for Access Token

Now for the fun part – let's exchange that code for an access token:

const tokenResponse = await axios.post('https://launchpad.37signals.com/authorization/token', {
  type: 'web_server',
  client_id: clientId,
  client_secret: clientSecret,
  code: authCode,
  redirect_uri: redirectUri
});

const accessToken = tokenResponse.data.access_token;

Boom! You've got your access token. This is your golden ticket to the Basecamp API.

Refreshing the Access Token

Access tokens don't last forever, so we need to be ready to refresh them:

const refreshToken = async (refreshToken) => {
  const response = await axios.post('https://launchpad.37signals.com/authorization/token', {
    type: 'refresh',
    client_id: clientId,
    client_secret: clientSecret,
    refresh_token: refreshToken
  });
  return response.data.access_token;
};

Making Authenticated Requests

Now that we've got our access token, we can start making authenticated requests to the Basecamp API:

const userData = await axios.get('https://3.basecampapi.com/999999999/my/profile.json', {
  headers: { 'Authorization': `Bearer ${accessToken}` }
});

Best Practices

1. Store tokens securely: Never expose your tokens in client-side code or commit them to version control.
2. Handle errors gracefully: Always be prepared for things to go wrong and handle errors appropriately.
3. Respect rate limits: Basecamp has rate limits, so make sure you're not hammering their API too hard.

Conclusion

And there you have it! You've successfully implemented the authorization flow for your Basecamp 3 integration. Pat yourself on the back – you're well on your way to creating something awesome.

Remember, this is just the beginning. With this authorization flow in place, you can now start exploring all the amazing things you can do with the Basecamp API. The sky's the limit!

Additional Resources

Want to dive deeper? Check out these resources:

• Basecamp 3 API Documentation
• OAuth 2.0 Specification

Happy coding, and may your integrations be ever awesome!