Node JS/Express Webhook Example

const express = require( 'express' );
const app = express();
const API_SECRET = 'secret';

app.use( express.json( { verify: ( req, res, buffer ) => { req.rawBody = buffer; } } ) );

app.post( '/', ( req, res ) => {
  const signature = _generateSignature( req.method, req.url, req.headers[ 'x-cp-signature' ], req.rawBody );
  const ret = 200;

  if ( signature !== req.headers[ 'x-cp-signature' ] ) {
    ret = 403;
  }
  else {
    ret = 200;
  }
  res.sendStatus(ret);
} );

app.listen( 9000, () => console.log( 'Node.js server started on port 9000.' ) );

function _generateSignature( method, url, timestamp, body ) {
  const hmac = crypto.createHmac( 'SHA256', API_SECRET );
  hmac.update( `${ method.toUpperCase() }${ url }${ timestamp }` );
  if ( body ) {
      hmac.update( body );
  }
  return hmac.digest( 'hex' );
}