Quick Guide to Implementing Webhooks in PandaDoc

Hey there, fellow JavaScript dev! Ready to supercharge your PandaDoc integration with webhooks? Let's dive right in and get those real-time updates flowing!

Introduction

Webhooks are like your app's personal news reporters, delivering the latest updates from PandaDoc straight to your doorstep. They're crucial for keeping your integration in sync and your users happy. We'll be using the PandaDoc API to set these up, so buckle up!

Prerequisites

Before we start, make sure you've got:

• A PandaDoc API key (your golden ticket)
• Node.js installed (you're a JS dev, so I'm sure you're covered)
• A basic grasp of Express.js (we'll use it for our webhook endpoint)

Got all that? Great! Let's code!

Setting Up Webhook Endpoint

First things first, we need a place for PandaDoc to send those juicy updates. Let's whip up a quick Express server:

const express = require('express');
const app = express();
app.use(express.json());

app.post('/webhook', (req, res) => {
  console.log('Webhook received:', req.body);
  res.sendStatus(200);
});

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

This sets up a simple endpoint at /webhook. It'll log the incoming data and send a 200 OK response. Easy peasy!

Registering a Webhook with PandaDoc API

Now, let's tell PandaDoc where to send those updates. We'll use axios to make the API request:

const axios = require('axios');

axios.post('https://api.pandadoc.com/public/v1/webhooks', {
  name: 'My Awesome Webhook',
  url: 'https://your-domain.com/webhook',
  events: ['document_state_changed', 'document_updated']
}, {
  headers: {
    'Authorization': 'API-Key YOUR_API_KEY_HERE',
    'Content-Type': 'application/json'
  }
})
.then(response => console.log('Webhook registered:', response.data))
.catch(error => console.error('Registration failed:', error));

Replace YOUR_API_KEY_HERE with your actual API key, and update the URL to where your webhook endpoint is hosted.

Handling Webhook Events

When a webhook hits your endpoint, you'll want to do something useful with it. Here's a basic example:

app.post('/webhook', (req, res) => {
  const { event_type, data } = req.body;
  
  switch(event_type) {
    case 'document_state_changed':
      console.log(`Document ${data.id} changed state to ${data.status}`);
      break;
    case 'document_updated':
      console.log(`Document ${data.id} was updated`);
      break;
    default:
      console.log(`Received event: ${event_type}`);
  }
  
  res.sendStatus(200);
});

This gives you a starting point to handle different event types. Feel free to add your own logic!

Verifying Webhook Authenticity

Trust, but verify! PandaDoc signs each webhook, so let's check that signature:

const crypto = require('crypto');

app.post('/webhook', (req, res) => {
  const signature = req.headers['x-pandadoc-signature'];
  const body = JSON.stringify(req.body);
  const hash = crypto.createHmac('sha256', 'YOUR_WEBHOOK_SECRET')
                     .update(body)
                     .digest('hex');
  
  if (hash !== signature) {
    return res.status(401).send('Invalid signature');
  }
  
  // Process the webhook...
});

Replace 'YOUR_WEBHOOK_SECRET' with the secret PandaDoc provides when you set up the webhook.

Error Handling and Retry Logic

Sometimes things go wrong. Let's add some basic retry logic:

const MAX_RETRIES = 3;

function processWebhook(data, attempt = 1) {
  try {
    // Your webhook processing logic here
  } catch (error) {
    if (attempt < MAX_RETRIES) {
      console.log(`Retry attempt ${attempt}`);
      setTimeout(() => processWebhook(data, attempt + 1), 1000 * attempt);
    } else {
      console.error('Max retries reached:', error);
    }
  }
}

app.post('/webhook', (req, res) => {
  res.sendStatus(200); // Always respond quickly to PandaDoc
  processWebhook(req.body);
});

This will retry up to 3 times with increasing delays between attempts.

Testing Webhooks

PandaDoc offers webhook testing tools, but you can also simulate events locally:

// Simulate a webhook event
axios.post('http://localhost:3000/webhook', {
  event_type: 'document_state_changed',
  data: { id: '123', status: 'completed' }
})
.then(() => console.log('Test webhook sent'))
.catch(error => console.error('Test failed:', error));

Run this in a separate file to test your webhook handling.

Best Practices

1. Idempotency: Make sure processing a webhook twice doesn't cause issues.
2. Logging: Log everything. You'll thank yourself later.
3. Scalability: As you grow, consider using a message queue for processing webhooks.

Conclusion

And there you have it! You're now ready to implement webhooks like a pro. Remember, webhooks are powerful tools that keep your app in sync with PandaDoc. Use them wisely, and your users will love the real-time updates.

Keep coding, keep learning, and don't forget to check out the PandaDoc API docs for more advanced features. You've got this! 🐼🚀