How to use ForEach controller on an array? - jmeter

Question

jmeter ForEach controller can be used to iterate over variables with same prefix like,
myVar_1
myVar_2
myVar_3
But in my case input variable is array of strings, [ "val1", "val2", "val3" ] How to iterate over an array and send separate request for each value?

Answer 1

You won't be able to feed this JSON Array to the ForEach Controller, but you can convert it into a form which can be understood by the ForEach Controller
Add a JSR223 Sampler after the variable holding this JSON Array is defined
Put the following code into the "Script" area:
def json = new groovy.json.JsonSlurper().parseText(vars.get("yourInputVariable"))
def counter = 1
json.each {
vars.put("myVar_" + counter, it)
counter++
}
Replace yourInputVariable with the actual name of the variable holding the JSON Array
Add ForEach Controller under the JSR223 Sampler and perform "normal" configuration as you would do it for myVar_1, myVar_2,... - it will work fine as JSR223 Sampler creates the relevant variables basing on the data from the JSON Array.
See Parsing and producing JSON - Groovy and Groovy Is the New Black articles for more information.

Answer 2

Same way as you use for same prefixed variables.
For variable myVar
myVar = ["val1", "val2", "val3"];
//Following variables are automatically created
myVar_1 = "val1";
myVar_2 = "val2";
myVar_3 = "val3";
ForEach controller will be used on myVar_1, myVar_2, myVar_3
Use Debug Sampler to ensure.
jmeter version : 3.1 r1770033

Answer 3

I tried Dmitri's answer, but basically got stuck with the groovy script as it works only for a simple array of strings. I, however, needed a more complex array of JSON objects.
Then I switched the scripting language to ecmascript and based on the original script wrote a good old JS like this:
var jsonObject = JSON.parse(vars.get("ReportSources"));
for(var index = 0; index < jsonObject.length; index++) {
vars.put("rs_" + (index + 1), JSON.stringify(jsonObject[index]));
}
It worked for me.