typeform webhook handler for google cloudfunction

index.js

const functions = require('@google-cloud/functions-framework');
const crypto = require('crypto');

const SECRET_TOKEN = "abc123"

functions.http('webhookHandler', (req, res) => {
  // Ensure the request body is available as a string
  const rawBody = req.rawBody ? req.rawBody.toString() : JSON.stringify(req.body);

  const signature = req.headers['typeform-signature'];
  const isValid = verifySignature(signature, rawBody);

  if (isValid) {
    // Process the webhook payload here
    console.log('Webhook signature verified');
    res.status(200).send('Webhook received and verified');
  } else {
    console.error('Invalid webhook signature');
    res.status(403).send('Invalid signature');
  }
});


const verifySignature = function (receivedSignature, payload) {
  const hash = crypto
    .createHmac('sha256', SECRET_TOKEN)
    .update(payload)
    .digest('base64');
  return receivedSignature === `sha256=${hash}`;
};