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

Aug 14, 2024 • 6 minute read

Introduction

Hey there, fellow JavaScript enthusiast! Ready to dive into the world of SignNow integration? Today, we're going to tackle one of the most crucial parts of building a public SignNow integration: the authorization flow. Trust me, getting this right is key to a smooth, secure user experience. So, let's roll up our sleeves and get to work!

Prerequisites

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

A SignNow developer account (if you don't have one, go grab it!)
A registered application with your client ID and secret (keep these safe, you'll need them soon)

Authorization Flow Overview

We'll be using the OAuth 2.0 protocol, specifically the Authorization Code Grant flow. Don't worry if that sounds like a mouthful – it's actually pretty straightforward once we break it down.

Implementing the Authorization Flow

Initiating the auth request

First things first, we need to send our users to SignNow's authorization page. Here's how:

const authUrl = `https://app.signnow.com/authorize?client_id=${YOUR_CLIENT_ID}&redirect_uri=${YOUR_REDIRECT_URI}&response_type=code`;

// Redirect the user to this URL
window.location.href = authUrl;

Handling the callback

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

const urlParams = new URLSearchParams(window.location.search);
const code = urlParams.get('code');

if (code) {
  // We've got the code! Let's exchange it for an access token
} else {
  // Uh-oh, something went wrong. Handle the error.
}

Exchanging the code for an access token

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

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

  const data = await response.json();
  // Store this token securely!
  return data.access_token;
}

Refreshing the access token

Access tokens don't last forever, so let's make sure we can refresh them:

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

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

Best Practices

Remember, with great power comes great responsibility:

Always use HTTPS
Store tokens securely (consider using HttpOnly cookies or secure storage solutions)
Implement proper error handling and provide clear feedback to your users

Testing the Authorization Flow

Before you ship it, test it! Use tools like Postman to simulate the flow. If you run into issues, double-check your client ID, secret, and redirect URI. And don't forget to check those network requests – they often hold the clues you need!

Conclusion

And there you have it! You've just built the authorization flow for your SignNow integration. Pretty cool, right? With this foundation, you're all set to start making API calls and building out the rest of your integration.

Additional Resources

Want to dive deeper? Check out:

Remember, building integrations is all about learning and iterating. Don't be afraid to experiment and ask questions. You've got this! Happy coding!