Webhooks

// Express.js example
const express = require('express');
const app = express();
 
app.use(express.json());
 
app.post('/webhook/n0mad', (req, res) => {
  const { event, data, signature, timestamp } = req.body;
  
  // Verify webhook signature
  if (!verifySignature(req.body, req.headers['x-n0mad-signature'])) {
    return res.status(401).send('Unauthorized');
  }
  
  // Process the webhook event
  handleWebhookEvent(event, data);
  
  res.status(200).send('OK');
});
 
app.listen(3000, () => {
  console.log('Webhook server listening on port 3000');
});

POST /v1/webhooks
Content-Type: application/json
Authorization: Bearer YOUR_API_TOKEN
 
{
  "url": "https://your-domain.com/webhook/n0mad",
  "events": [
    "transaction.confirmed",
    "balance.updated",
    "price.alert",
    "stake.reward"
  ],
  "secret": "your-webhook-secret",
  "active": true
}

{
  "success": true,
  "data": {
    "webhook_id": "wh_123456789",
    "url": "https://your-domain.com/webhook/n0mad",
    "events": ["transaction.confirmed", "balance.updated"],
    "created_at": "2024-10-24T07:37:42Z",
    "active": true
  }
}

const crypto = require('crypto');
 
function verifySignature(payload, signature, secret) {
  const expectedSignature = crypto
    .createHmac('sha256', secret)
    .update(JSON.stringify(payload))
    .digest('hex');
    
  return `sha256=${expectedSignature}` === signature;
}

GET /v1/webhooks
Authorization: Bearer YOUR_API_TOKEN

{
  "success": true,
  "data": {
    "webhooks": [
      {
        "webhook_id": "wh_123456789",
        "url": "https://your-domain.com/webhook/n0mad",
        "events": ["transaction.confirmed", "balance.updated"],
        "active": true,
        "created_at": "2024-10-24T07:37:42Z",
        "last_triggered": "2024-10-24T09:15:00Z"
      }
    ],
    "total_count": 1
  }
}

PUT /v1/webhooks/{webhook_id}
Content-Type: application/json
Authorization: Bearer YOUR_API_TOKEN
 
{
  "url": "https://new-domain.com/webhook/n0mad",
  "events": ["transaction.confirmed", "price.alert"],
  "active": true
}

DELETE /v1/webhooks/{webhook_id}
Authorization: Bearer YOUR_API_TOKEN

POST /v1/webhooks/{webhook_id}/test
Authorization: Bearer YOUR_API_TOKEN

const processedEvents = new Set();
 
function handleWebhookEvent(event, data) {
  const eventId = data.transaction_id || data.alert_id || data.user_id;
  
  if (processedEvents.has(eventId)) {
    console.log('Event already processed:', eventId);
    return;
  }
  
  // Process the event
  processEvent(event, data);
  
  // Mark as processed
  processedEvents.add(eventId);
}

app.post('/webhook/n0mad', (req, res) => {
  try {
    // Process webhook
    handleWebhookEvent(req.body.event, req.body.data);
    res.status(200).send('OK');
  } catch (error) {
    console.error('Webhook processing failed:', error);
    // Return 5xx status to trigger retry
    res.status(500).send('Internal Server Error');
  }
});

app.post('/webhook/n0mad', (req, res) => {
  const signature = req.headers['x-n0mad-signature'];
  const timestamp = req.headers['x-n0mad-timestamp'];
  
  // Verify timestamp (prevent replay attacks)
  if (Date.now() - parseInt(timestamp) > 300000) { // 5 minutes
    return res.status(401).send('Request too old');
  }
  
  // Verify signature
  if (!verifySignature(req.body, signature, process.env.WEBHOOK_SECRET)) {
    return res.status(401).send('Invalid signature');
  }
  
  // Process webhook...
});

function handleWebhookEvent(event, data) {
  console.log('Webhook received:', {
    event,
    timestamp: new Date().toISOString(),
    data: JSON.stringify(data)
  });
  
  try {
    processEvent(event, data);
    console.log('Webhook processed successfully:', event);
  } catch (error) {
    console.error('Webhook processing error:', error);
    throw error;
  }
}

// Webhook metrics tracking
const webhookMetrics = {
  totalReceived: 0,
  totalProcessed: 0,
  totalErrors: 0,
  lastReceived: null,
  processingTimes: []
};
 
app.post('/webhook/n0mad', (req, res) => {
  const startTime = Date.now();
  webhookMetrics.totalReceived++;
  webhookMetrics.lastReceived = new Date().toISOString();
  
  try {
    handleWebhookEvent(req.body.event, req.body.data);
    webhookMetrics.totalProcessed++;
    res.status(200).send('OK');
  } catch (error) {
    webhookMetrics.totalErrors++;
    res.status(500).send('Error');
  } finally {
    const processingTime = Date.now() - startTime;
    webhookMetrics.processingTimes.push(processingTime);
    
    // Keep only last 100 processing times
    if (webhookMetrics.processingTimes.length > 100) {
      webhookMetrics.processingTimes.shift();
    }
  }
});
 
// Health check endpoint
app.get('/webhook/health', (req, res) => {
  res.json(webhookMetrics);
});