express-js-git-webhook.js

const express = require('express');
const crypto = require('crypto');
require('dotenv/config');

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

app.post('/mentor', function (req, res) {
  const { SECRET_KEY } = process.env
  const { body, headers } = req

  // Create Signature from Request Body
  const expectedSignature = `sha1=${crypto.createHmac('sha1', SECRET_KEY).update(JSON.stringify(body).digest('hex'))}`

  // Compare the signature against the one in the request
  const signature = headers["x-hub-signature"];
  if (signature !== expectedSignature) {
    throw new Error("Invalid signature.");
  }
  res.send('API Works');
})

app.listen(8081, function () {
  console.log('Listening on Port 8081');
})