Unexpected Automation: Creating a randomised HTTP payload

After a bit of a break for the summer holiday, and as promised in Quickly creating test data in MongoDB</a>, here is a look at how we can use the randomisation script script from Quickly creating test data in MongoDB</a> to create a randomised HTTP payload for POST requests.

However, before we begin, let’s refresh ourselves with the randomisation script:

var name = ["Mark","Mary","Sally","Jim","Eric","Susan"]
var surname = ["Jones","Wilson","Jackson","Brown","Smith","Ericsson"]

var randomiseNumber = function(from, to){
  return Math.floor(Math.random() * (to - from + 1)) + from;

var randomiseDate = function(start, end) {
  return new Date(start.getTime() + Math.random() * (end.getTime() - start.getTime()));

var latestDate = new Date()
var checkInDate = randomiseDate(new Date(2013, 1, 1),latestDate)

var booking = { 
  "firstname": name[randomiseNumber(0,name.length - 1)], 
  "lastname": surname[randomiseNumber(0,surname.length - 1)], 
  "totalprice": randomiseNumber(100,1000), 
  "depositpaid": Math.random() >= 0.5,
  "bookingdates": {
    "checkin": checkInDate,
    "checkout": randomiseDate(checkInDate,latestDate)

if(Math.random() >= 0.5){
  booking.additionalneeds = "Breakfast";


Creating a randomised JSON payload

JSON is an extremely popular choice for payloads in HTTP requests and because of the earlier work on the script we can use it straight off the bat to create a JSON payload. Simply take the output of the randomised data and use that in your POST request.

Creating a randomised XML payload

Another widely used content type for POST requests is XML. But since the script only offers the ability to create data in JSON format we need to update it a bit to make it produce an XML payload. One way would be to concatenate strings to build up an XML payload but that would be a lot of work ending in a very different (and probably messy looking) script and it may be desirable to have a script that can easily switch between JSON and XML creation.

Therefore, we are going to use the js2xmlparser library to convert the JSON into XML like so:

  • First download the library by running npm install js2xmlparser in the directory your script is saved.</li>
  • Add to the top of the script var js2xmlparser = require("js2xmlparser");</li>
  • Replace console.log(booking) at the bottom of the script with console.log(js2xmlparser("booking", booking));</li>

The js2xmlparser method takes two parameters:

  1. The first parameter determines the parent tag that the randomised data is injected into. Since we are creating a booking we name it "booking". (This might be a little confusing since the second parameter is named booking so try changing the name and observing what happens)
  2. The second parameter takes the JSON object we have created and converts it into XML format

Once you have it set up, give it a try. You should end up with an output like this:

<?xml version="1.0" encoding="UTF-8"?>
      <checkin>Fri Jun 28 2013 19:57:28 GMT+0100 (BST)</checkin>
      <checkout>Sat Aug 09 2014 00:31:00 GMT+0100 (BST)</checkout>

Wrapping up

With either of these solutions you can create a quick and easy script to produce a randomised payload that can then be dropped into your tool of choice.