How to create a dynamic request in Jmeter - json

Question

I have a response from an API
[{
"userSourceMeta": {
"userId": "sss#gmail.com",
"source": "BOX",
"organisationId": 1,
"emailId": "sss#gmail.com",
"sourceUserId": "15548727375",
"accessToken": null,
"refreshToken": null,
"lastCursorPosition": null,
"lastAccessTime": 1626025027228,
"name": "John",
"createdAt": 1622444279509
},
"connectionStatus": null}, {
"userSourceMeta": {
"userId": "test#gmail.com",
"source": "ONEDRIVE",
"organisationId": 1,
"emailId": "sss#outlook.com",
"sourceUserId": "3969b928a1a28f34",
"accessToken": null,
"refreshToken": null,
"lastCursorPosition": null,
"lastAccessTime": 1626025027228,
"name": "sss ddd",
"createdAt": 1624262423446
},
"connectionStatus": null}]
I have to use two parameters in the successive request(source,sourceUserId) . This is a dynamic request it can be varied 3, 4,5 ..etc.
Next API request.
{
"Answer": "My name is xyz",
"queryChannel": "WEB_APP",
"timeZone": "Asia/Calcutta",
"sourceFilterInfo": [{
"sourceUserId": "15548727375",
"source": "BOX"
}, {
"sourceUserId": "3969b928a1a28f34",
"source": "ONEDRIVE"
}],
"contextIds": []
}
Please provide a solution to send a dynamic request with the previous API response.
I used regular expression extractor to store values. But how to send it in a request.

Answer 1

Add JSR223 PostProcessor as a child of the request which returns the above JSON and put the following code into "Script" area:
def response = new groovy.json.JsonSlurper().parse(prev.getResponseData())
def sourceFilterInfo = []
response.each { entry ->
def user = [sourceUserId: entry['userSourceMeta'].sourceUserId, source: entry['userSourceMeta'].source]
sourceFilterInfo.add(user)
}
def payload = [:]
payload.put('Answer', 'My name is xyz')
payload.put('queryChannel', 'WEB_APP')
payload.put('timeZone', 'Asia/Calcutta')
payload.put('sourceFilterInfo', sourceFilterInfo)
payload.put('contextIds', [])
vars.put('payload', new groovy.json.JsonBuilder(payload).toPrettyString())
That's it, now you should be able to refer the generated request as ${payload} where required
More information:
Apache Groovy - Parsing and producing JSON
Apache Groovy - Why and How You Should Use It