How to build a public Capsule CRM integration: Building the Auth Flow

Aug 16, 2024 • 7 minute read

Hey there, fellow JavaScript aficionado! Ready to dive into the world of Capsule CRM integration? Today, we're focusing on the crucial part of any integration: the authorization flow. Buckle up, because we're about to make your Capsule CRM integration dreams come true!

Prerequisites

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

Your favorite JavaScript environment set up
A Capsule CRM developer account (if you don't have one, go grab it!)
Your Capsule CRM API credentials (client ID and secret)
A good cup of coffee (optional, but highly recommended)

Understanding Capsule CRM OAuth 2.0 Flow

Capsule CRM uses OAuth 2.0 with the authorization code grant. It's like a secret handshake between your app and Capsule CRM. Here's the gist:

Your app asks for permission
User says "Sure, go ahead!"
Capsule gives you a special code
You trade that code for an access token
Voila! You're in!

The key endpoints you'll be working with are:

Authorization: https://api.capsulecrm.com/oauth/authorise
Token: https://api.capsulecrm.com/oauth/token

Setting Up the Authorization Request

Time to craft that authorization URL. It's like making a sandwich - you need all the right ingredients:

const authUrl = new URL('https://api.capsulecrm.com/oauth/authorise');
authUrl.searchParams.append('client_id', YOUR_CLIENT_ID);
authUrl.searchParams.append('redirect_uri', YOUR_REDIRECT_URI);
authUrl.searchParams.append('response_type', 'code');
authUrl.searchParams.append('state', generateRandomState()); // For security!

Pro tip: That state parameter? It's your shield against CSRF attacks. Don't skip it!

Handling the Authorization Callback

Once the user gives the thumbs up, Capsule CRM will ping your redirect URI. It's like getting a text from your crush - exciting, right?

app.get('/callback', (req, res) => {
  const { code, state } = req.query;
  
  if (state !== storedState) {
    return res.status(400).send('State mismatch. Possible CSRF attack.');
  }
  
  // Time to exchange this code for an access token!
});

Exchanging the Authorization Code for Access Token

Now for the grand finale - turning that code into an access token:

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

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

Remember to store these tokens securely. They're the keys to the kingdom!

Implementing Token Refresh

Access tokens don't last forever. When they expire, it's refresh time:

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

  return response.json();
};

Error Handling and Edge Cases

Things don't always go smoothly. Be prepared for:

Invalid or expired tokens
Network issues
API rate limits

Always check the response status and handle errors gracefully. Your users will thank you!

Best Practices for User Experience

Make the auth flow smooth like butter:

Clear instructions
Progress indicators
Friendly error messages

Remember, a happy user is a returning user!

Testing the Authorization Flow

Before you ship it, test it! Set up a mock server, simulate different scenarios, and try to break your own code (it's fun, trust me).

Conclusion

And there you have it! You've just built a rock-solid authorization flow for your Capsule CRM integration. Pat yourself on the back - you've earned it!

Next steps? Start building out those API calls and create something awesome. The sky's the limit!

Additional Resources

Want to dive deeper? Check out:

Now go forth and integrate! And remember, with great access comes great responsibility. Use your newfound power wisely!