Postman Script for JWT with MD5 request body

postman-pre-script.js

var removeIllegalCharacters = function(input) {
    return input
        .replace(/=/g, '')
        .replace(/\+/g, '-')
        .replace(/\//g, '_');
};

var base64object = function(input) {
    var inputWords = CryptoJS.enc.Utf8.parse(JSON.stringify(input));
    var base64 = CryptoJS.enc.Base64.stringify(inputWords);
    var output = removeIllegalCharacters(base64);
    return output;
};

var clientKey = postman.getEnvironmentVariable('client_key');
var clientSecret = postman.getEnvironmentVariable('client_secret');

var url = request.url;
var slashIndex = url.toLowerCase().startsWith('http') ? 8 : 0;
var path = url.substring(url.indexOf('/', slashIndex), url.length);

var exp = Date.now() + 15000;
var nbf = Date.now() + 5000;
var mth = request.method;
var data = "";
if(Object.keys(request.data).length !== 0) {
    data = request.data;
}
var jti = CryptoJS.MD5(data).toString();
var header = { 'alg': 'HS256', 'typ': 'JWT' };
var payload = { 'exp': exp, 'nbf': nbf, 'iss': clientKey, 'jti': jti };

var unsignedToken = base64object(header) + "." + base64object(payload);

var signatureHash = CryptoJS.HmacSHA256(unsignedToken, clientSecret);
var signature = CryptoJS.enc.Base64.stringify(signatureHash);
var token = unsignedToken + '.' + signature;

postman.setGlobalVariable('jwt_token', removeIllegalCharacters(token));