Process and Route Incoming Webhook Events to Specific Handlers

const express = require('express');
const bodyParser = require('body-parser');

const app = express();
const PORT = process.env.PORT || 3000;

// Use raw body parser for webhooks to allow signature verification (if needed)
// For this example, we assume verification happens before or is not required.
app.use(bodyParser.json({ verify: (req, res, buf) => { req.rawBody = buf; } }));

// --- Webhook Handlers ---
const handleUserCreated = (eventData) => {
  console.log('User Created Event:', eventData);
  // Implement logic for user creation, e.g., create user in database, send welcome email
};

const handleOrderPaid = (eventData) => {
  console.log('Order Paid Event:', eventData);
  // Implement logic for order payment, e.g., update order status, notify shipping
};

const handleDefaultEvent = (eventData, eventType) => {
  console.log(`Unhandled Event Type '${eventType}':`, eventData);
  // Log unhandled events or send alerts
};

const eventHandlers = {
  'user.created': handleUserCreated,
  'order.paid': handleOrderPaid,
  // Add more event types and their respective handler functions
};

app.post('/webhook-receiver', (req, res) => {
  const event = req.body; // Assuming the webhook payload is JSON

  // Basic check for expected event structure
  if (!event || !event.type) {
    console.error('Invalid webhook payload: missing event type.', event);
    return res.status(400).send('Invalid webhook payload');
  }

  const eventType = event.type;
  const eventData = event.data; // Assuming event data is nested under 'data' key

  console.log(`Received webhook event: ${eventType}`);

  const handler = eventHandlers[eventType] || handleDefaultEvent;

  try {
    handler(eventData, eventType); // Pass eventType for default handler
    res.status(200).send('Webhook received and processed');
  } catch (error) {
    console.error(`Error processing webhook event ${eventType}:`, error);
    res.status(500).send('Error processing webhook');
  }
});

app.listen(PORT, () => {
  console.log(`Webhook receiver running on port ${PORT}`);
});