Retrieve HTTP Digest Data from WWW-Authenticate header in 401 Response from Server

Based on some stackoverflow answers a possible solution is splitting the WWW-Authenticate header by comma, then put each key value pair in a map collection.

https://stackoverflow.com/questions/45361721/groovy-digest-authentication

https://stackoverflow.com/questions/1757065/java-splitting-a-comma-separated-string-but-ignoring-commas-in-quotes

See if this groovy script sets the property values that you want. 

import org.apache.commons.codec.digest.DigestUtils

def user = "sip:381117508016@ims.telekomsrbija.com";
def pass = "bzlops16";
def request = testRunner.testCase.testSteps["HTTP_Get_FirstHit"].testRequest;
def headerauth = request.response.responseHeaders["WWW-Authenticate"][0];

def values = headerauth.split(',(?=(?:[^\"]*\"[^\"]*\")*[^\"]*$)', 0);
def map = [:];
values.eachWithIndex {it, index ->
	def pair = values[index].tokenize('=')
	map.put(pair[0].trim(), pair[1].trim().replace('"',''))
}

def realm = map["Digest realm"];
def qop = map["qop"];
def nonce = map["nonce"];
def opaque = map["opaque"];

def method = request.getMethod()
def uri = request.getEndpoint();
def response = md5(user, realm, pass, method, uri, nonce);
log.info response

def md5(user, realm, pass, method, String uri, nonce) {
def A1 = DigestUtils.md5Hex ("$user:$realm:$pass")
def A2 = DigestUtils.md5Hex ("$method:$uri")
DigestUtils.md5Hex ("$A1:$nonce:$A2")
}

def init = testRunner.testCase.getTestStepByName( "Properties" );
 init.setPropertyValue( "realm", realm);
 init.setPropertyValue( "nonce", nonce);
 init.setPropertyValue( "opaque", opaque);
 init.setPropertyValue( "response", response);
 init.setPropertyValue( "uri", uri);