How to setup Github Webhooks using Node.js

github_webhooks.js

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

const app = express()

// To include rawBody in req parameter
app.use(bodyParser.json({
  verify: (req, res, buf) => {
    req.rawBody = buf
  }
}))

app.post('/github', (req, res) => {
  const secret = "YOUR_SECRET_HERE"
  
  const signature = Buffer.from('sha256=' + crypto
          .createHmac('sha256', secret)
          .update(req.rawBody)
          .digest('hex'), 'utf-8')
  
  // For secure compare use a secure comaprision method 
  if(signature.length !== req.headers['x-hub-signature-256'].length ||
          req.headers['x-hub-signature-256'] !==  signature.toString()){
          console.log("Invalid Signature");
          return res.status(401).end();
  }

  return res.status(200).send('Authentication complete')
})

app.listen(5000, () => console.log("Server running on port 5000"))


/**
  References
  1. https://www.digitalocean.com/community/tutorials/how-to-use-node-js-and-github-webhooks-to-keep-remote-projects-in-sync
  2. https://docs.github.com/en/developers/webhooks-and-events/creating-webhooks
**/