How to build a public Formidable Forms integration: Building the Auth Flow

Hey there, fellow JavaScript wizards! Ready to dive into the exciting world of Formidable Forms integrations? Today, we're going to focus on the crucial part of any integration: the authorization 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 your favorite code editor fired up and you're familiar with the basics of the Formidable Forms API. We'll be using Node.js and Express for this guide, so have those installed and ready to go.

Setting up the project

Let's kick things off by setting up our project:

mkdir formidable-integration
cd formidable-integration
npm init -y
npm install express axios dotenv

Create an .env file to store your Formidable Forms API credentials:

FORMIDABLE_CLIENT_ID=your_client_id
FORMIDABLE_CLIENT_SECRET=your_client_secret
REDIRECT_URI=http://localhost:3000/callback

Designing the Auth Flow

We'll be implementing the OAuth 2.0 Authorization Code Flow. It's secure, user-friendly, and perfect for our integration. Here's a quick overview:

1. User initiates the auth process
2. We redirect them to Formidable Forms for authorization
3. User grants permission
4. Formidable Forms redirects back with an auth code
5. We exchange the auth code for access and refresh tokens

Sound good? Let's make it happen!

Implementing the Authorization Request

Create an index.js file and let's get coding:

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

app.get('/auth', (req, res) => {
  const authUrl = `https://formidableforms.com/oauth/authorize?` +
    `client_id=${process.env.FORMIDABLE_CLIENT_ID}&` +
    `redirect_uri=${encodeURIComponent(process.env.REDIRECT_URI)}&` +
    `response_type=code&scope=forms`;
  
  res.redirect(authUrl);
});

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

When a user hits the /auth endpoint, we'll redirect them to Formidable Forms to grant permissions.

Handling the Authorization Callback

Now, let's handle the callback:

const axios = require('axios');

app.get('/callback', async (req, res) => {
  const { code } = req.query;
  
  try {
    const tokenResponse = await axios.post('https://formidableforms.com/oauth/token', {
      grant_type: 'authorization_code',
      client_id: process.env.FORMIDABLE_CLIENT_ID,
      client_secret: process.env.FORMIDABLE_CLIENT_SECRET,
      code,
      redirect_uri: process.env.REDIRECT_URI
    });

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

Token Management

Great job! Now we've got our tokens. But wait, there's more! Let's add a refresh mechanism:

async function refreshAccessToken(refresh_token) {
  try {
    const response = await axios.post('https://formidableforms.com/oauth/token', {
      grant_type: 'refresh_token',
      client_id: process.env.FORMIDABLE_CLIENT_ID,
      client_secret: process.env.FORMIDABLE_CLIENT_SECRET,
      refresh_token
    });

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

Making Authenticated Requests

Now that we've got our access token, let's use it to make a request:

async function getForms(access_token) {
  try {
    const response = await axios.get('https://formidableforms.com/api/v1/forms', {
      headers: { Authorization: `Bearer ${access_token}` }
    });

    return response.data;
  } catch (error) {
    if (error.response && error.response.status === 401) {
      // Token expired, refresh and try again
      const new_access_token = await refreshAccessToken(refresh_token);
      return getForms(new_access_token);
    }
    throw error;
  }
}

Security Considerations

To beef up security, implement PKCE (Proof Key for Code Exchange) and add CSRF protection. These are crucial for public integrations, so don't skip this step!

Testing the Auth Flow

Time to put our code to the test! Fire up your server and navigate to http://localhost:3000/auth. If all goes well, you should be redirected to Formidable Forms, then back to your app with a success message.

Conclusion

And there you have it, folks! You've just built a secure authorization flow for your Formidable Forms integration. Pretty cool, right? Remember, this is just the beginning. From here, you can expand your integration to do all sorts of amazing things with forms.

Keep coding, keep learning, and most importantly, keep being awesome! If you run into any snags, don't hesitate to dive into the Formidable Forms documentation or reach out to the community. Happy integrating!