Jmeter generate json payload of request dynamically

Question

I have a Jmeter test plan where I want my HttpSampler to send a post request.

The body of the request should contain Json as follows:

{
  "productIds" : [
    "p1",
    "p2",
    ...
  ]
}

I have setup a random variable generator that returns well-formed productId with every call. What I would like to do is generating the payload by filling productIds of random pid's taken from the generator, directly in the body of the request. Something like (suppose *** is the scripting escape):

{
  "productIds" : [
     ***
       for i in (1, $productsCount) {
         write("\"$randomPid\"\n")
       }
     ***
  ]
}

Is it possible? If yes, how? If not, how would you approach the issue?

Thanks!

Dmitri T · Accepted Answer · 2014-12-05 13:11:24Z

17

Add a Beanshell PreProcessor as a child of the request you want to parametrize

Put following code into the PreProcessor's "Script" area:

StringBuilder result = new StringBuilder();
String newline = System.getProperty("line.separator");
int max = Integer.parseInt(Parameters);
Random random = new Random();

result.append("{");
result.append("\"productIds\" : [");
result.append(newline);
for (int i = 1; i < max; i++) {
    result.append("\"").append(random.nextInt()).append("\",");
    result.append(newline);
}
result.append("]");
result.append(newline);
result.append("}");

vars.put("json", result.toString());

Put your ${productsCount} value into "Parameters" stanza
Refer generated payload as ${json} where required

See How to use BeanShell: JMeter's favorite built-in component guide for more details on Beanshell scripting in Apache JMeter.

answered Dec 5, 2014 at 13:11

Dmitri T

169k6 gold badges91 silver badges149 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Diego Martinoia Over a year ago

Yeah, that's the way I did it before seeing your answer, was wondering if it was possible to do within the http request payload directly, but this is also ok. Thanks!

Dmitri T Over a year ago

You can use __Beanshell function right in the request body but the whole approach from coding perspective will be the same

Hubbitus Over a year ago

Official documentation now recommends using JSR223 PreProcessor + Groovy instead of BeanShell PreProcessor.

Collectives™ on Stack Overflow

Jmeter generate json payload of request dynamically

1 Answer 1

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related