Qants – Tips in the field of Java Performance & Software Testing

The current project that i work for, was implemented to support JSON (JavaScript Object Notation) for its services.  What is JSON, was my first question, and how will my WEB Testing behaviour change because of this?

Well, like most of the times, researching and old googling on the internet gave me the right answers to get me in a starting position. So let me just walk through the stepst that i have taken, in order to make my testplans send JSON payload together with my HTTP Post requests.

1. So what is JSON?
   JSON is simply a data format, but one which is more naturally fit for browser data consumption. The reason for this is that JSON is a subset to JavaScript, the de facto programming language used in all browsers. By structuring a data payload as a JSON response, you are effectively bypassing the need to parse an XML document in a browser — typically done via JavaScript of course — to get to the actual data. 

   In this sense, JSON uses a stripped down syntax compliant with the native JavaScript interpreter provided on all browsers. Access and navigation to JSON data is done through the same standard JavaScript notation used to access string, array or hashtable values in a typical JavaScript application. Listing 1.1 illustrates what a JSON payload would look like.
   Listing 1.1 : JSON payload example
   
   {“item”: {
   “description”: {
   “title”: “Backroad Mountain Bikes”,
   “name”: “Stump Jumper”,
   “color”: “chrome”,
   “image”: “/images/stumpjumper.jpg”,
   “sizes”: “17,18,19″
   },
   “cost”: {
   “salestax”: CA,
   “rate”: 7,
   “base”: 550,
   “custompaint”: 150,
   “warranty”: 50,
   “travelcase”: 150
   },
   “instock”: “yes”
   }}
   This example was taken from an article published in 2006, under the following link:
   JavaScript Object Notation for Ajax Web services

   Ok, so basically JSON works with brackets, square and round paranthesis. It does indeed follow pretty much the JavaScript notation. And it misses the end tags in xml, which can (not sure about it yet) generate extra payload if xml is used (of course, there are some extra chars there…)
   That being said, the only thing left was actually to integrate the JSON strings into my JMeter HTTP Request.

2. Send JSON Payload in HTTP Request using JMeter
   Nothing simpler than this (yeah, right…now i’m saying it)…The only thing to do is to add the JSON Payload as Variable to be sent with the request (check it in the HTTP Sampler Properties for the HTTP Request that you are sending to the server).You do not need to name your variable. Sending the JSON Payload as value, for an empty variable should do the trick. Just make sure you copy the JSON Payload accordingly.
   After posting the Request, you can analyze the result, by rendering the JSON Result, using JMeter’s integrated JSON Rendere (if you use the Result Tree, select your request, and go to the third tab, the one called “Response Data”, and from the bottom of the window, select “Render JSON”.

You thought it is going to be more than that? Nope, it’s that simple. And my next blog post will be about extracting values from a HTTP Request like that, returning a JSON String, and using it further in the Jmeter script as variables.

Enjoy,

Alex