CODEWITHSUNDEEP
jsonscriptingjmeter
Diego Martinoia
Diego Martinoia

Reputation: 4652

Jmeter generate json payload of request dynamically

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!

Upvotes: 6

Views: 24976

Answers (1)

Dmitri T
Dmitri T

Reputation: 168002

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

  2. 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());
  3. Put your ${productsCount} value into "Parameters" stanza
  4. 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.

Upvotes: 17

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