Jmeter - Extract JSON field value of a SENT request - json

Question

I am trying to obtain data from sent JSON and use it further in another request.
My sent JSON also has dynamic variables like ${data} so the trick is that it has to execute first in order to be able to extract.
Let's say I have the following SENT JSON:
{
"field_one": ${data1},
"field_three": [more data],
"field_two": ${data2}
}
Question is: How can I extract "field_one" and "field_two" values from the sent request?
Thanks

Answer 1

You don't need to extract them, they are ${data1} and ${data2} so you can re-use these JMeter Variables anywhere in the script.
If I don't understand something obvious or you need to copy the values to another JMeter Variables, you can extract them as follows:
Add JSR223 PostProcessor as a child of the request which sends above JSON
Put the following code into "Script" area:
def requestBody = new groovy.json.JsonSlurper().parseText(sampler.getArguments().getArgument(0).getValue())
vars.put('field_one', requestBody.field_one)
vars.put('field_two', requestBody.field_two)
That's it, now you should have ${field_one} and ${field_two} JMeter Variables holding the values you're looking for.
In the above example sampler stands for HTTPSamplerProxy and vars for JMeterVariables, check out Top 8 JMeter Java Classes You Should Be Using with Groovy for details on the above and other JMeter API shorthands available for JSR223 Test Elements.
More informaion:
JsonSlurper
Apache Groovy: Parsing and producing JSON