Creates a valid CRC response for Twitter webhook integration.

challenge-response.js

crypto = require('crypto');

// Example app consumer secret found in apps.twitter.com
APP_CONSUMER_SECRET = 'z3ZX4v7mAAUGykl3EcmkqbartmuW8VFOOzCloLx9Q45P0hLrFu';

// Example token provided by incoming GET request
TOKEN = '9b4507b3-9040-4669-9ca3-6b94edb50553';


/**
 * Creates a HMAC SHA-256 hash created from the app TOKEN and
 * your app Consumer Secret.
 * @param  token  the token provided by the incoming GET request
 * @return string
 */
function get_challenge_response(token) {

  hmac = crypto.createHmac('sha256', APP_CONSUMER_SECRET).update(TOKEN).digest('base64');

  response = {
    "response_token": "sha256=" + hmac
  }

  return JSON.stringify(response);
}

// prints result
console.log(get_challenge_response(TOKEN));