Jmeter Groovy Script to read and utilize header values - groovy

Question

I was using jmeter to load test services
I need to use one of the response headers parameter value as input of next request.
For this I am using JSR223 Sampler and write Grrovy Script to read parameters.
I have used
**def headerList = prev.getResponseHeaders()
headerList.each(){
headersList.each{
log.info it;
if(it.equals("transactionRef"){
log.info"Required Header: "it
requiredHeader=it;
}**
The above code is not working
also it is traversing character by character.
Could someone help on this.
}

Answer 1

As per the JavaDoc SampleResult.getResponseHeaders() function returns response headers as a single String so if you want to get individual headers you need to split it by line separators first and then by colon to get name/value pairs.
Example code:
def headers = prev.getResponseHeaders().split('\n').inject([:]) { out, header ->
if (header.contains(':')) {
header.split(':').with {
out[it[0].trim()] = it[1].trim()
}
}
out
}
headers.each { header ->
if (header.getKey() == 'transactionRef') {
log.info('Required header value: ' + header.getValue())
}
}
More information on Groovy scripting in JMeter: Apache Groovy - Why and How You Should Use It
P.S. Woudln't it be easier to go for Regular Expression Extractor? The relevant configuration would be something like: