shopify webhook integration node.js

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

const app = express()
const port = 3000

app.use(bodyParser());

app.post('/', (request, response) => {  
  
  var bodyMessage = JSON.stringify(request.body)

  bodyMessage = bodyMessage.split('/').join('\\/')
  bodyMessage = bodyMessage.split('&').join('\\u0026')

  var calculated_signature = crypto.createHmac('sha256', 'shopify_shared_secret')
  .update(bodyMessage.toString('utf8'))
  .digest('base64');

  console.log(request.headers['x-shopify-hmac-sha256'])
  console.log(calculated_signature)

})

app.get('/', (request, response) => {  
  response.json({
    chance: request.chance
  })
})

app.listen(port, (err) => {  
  if (err) {
    return console.log('something bad happened', err)
  }

  console.log(`server is listening on ${port}`)
})