Google App Script fetch request with Digest auth issue - google-apps-script

Question

I am trying to retrieve some info from the camera system DVR from HIK Vision with GAS' UrlFetchApp. I am able to perform a successful request with Postman but having trouble getting this to work with the Google App Script's UrlFetchApp.fetch. I confirmed that my Digest calculation is correct. I did that by substituting values for nonce, cnonce, qop etc in my GAS with the ones which were in Postman and got the same Response string as the Postman did. See images of the Postman below:
Postman gets a 200 response and all the data that I need.
The way my app works is it sends a first request and gets 401 response. Then it sends a second request with the auth header calculated from the data received from the first request. I always get 401 no matter what I do. I played with the double quotes in the headers properties etc.
Here's the code:
function getRecordedDaysCount(){
const url = 'my_server_url';
const userName = 'user';
const pass = "password";
const uri = "/ISAPI/ContentMgmt/record/tracks/101/dailyDistribution";
const method = "POST"
const updatedUrl = url + uri;
let year = '2021';
let month = '03';
//payload required by the server for this request
let payload = '<?xml version: "1.0" encoding="utf-8"?><trackDailyParam><year>' + year + '</year><monthOfYear>' + month + '</monthOfYear></trackDailyParam>';
let options = {
"method" : method,
"muteHttpExceptions": true,
"headers":{
"Accept": "application/xml, text/plain, */*",
}
}
let data = UrlFetchApp.fetch(updatedUrl, options);
if(data.getResponseCode() == 401){
let wwwAuthenticate = data.getAllHeaders()["WWW-Authenticate"];
// Example WWWAuthenticate
// "Digest realm="493b21e13dddb4ef7745edaa", domain="::", qop="auth",
// nonce="17fbf10682dc4a7ceb04206cbcd95d8d:1616709300571", opaque="", algorithm="MD5", stale="FALSE""
let authData = wwwAuthenticate.split(',');
let authType = authData[0].split(' ')[0]; // Digest
if(authType === "Digest"){
let realm = authData[0].split('"')[1]; // "493b21e13dddb4ef7745edaa"
let qop=authData[2].split('"')[1]; // "auth"
let nonce = authData[3].split('"')[1]; // "17fbf10682dc4a7ceb04206cbcd95d8d:1616709300571"
let algorithm = authData[5].split('"')[1]; // "MD5"
let nc="00000001";
let cnonce= new Date().getTime().toString(16);
let hash1 = signMD5(userName +':'+ realm +':'+ pass);
let hash2 = signMD5(method+':'+ uri);
let response = signMD5(hash1+':'+nonce+':'+nc+':'+cnonce+':'+qop+':'+hash2);
let digestAuth = "Digest username=\"" + userName + "\"" +
", realm=\"" + realm + "\"" +
", nonce=\"" + nonce + "\"" +
", uri=\"" + uri + "\"" +
", qop=auth" +
", nc=" + nc +
", algorithm=\"MD5\"" +
", cnonce=\"" + cnonce + "\"" +
", response=\"" + response + "\"";
let headers = {
"Content-Type": "text/plain", // copied from Postman
"Accept-Encoding": "gzip, deflate, br", // copied from Postman
"Authorization": digestAuth,
}
let options = {
"method" : method,
"muteHttpExceptions": true,
"headers": headers,
"payload": (payload)
}
logUrlFetch(updatedUrl, options);
}
}
}
function signMD5(message){
let signature = Utilities.computeDigest(
Utilities.DigestAlgorithm.MD5,
message,
Utilities.Charset.UTF_8);
let signatureStr = '';
for (i = 0; i < signature.length; i++) {
let byte = signature[i];
if (byte < 0)
byte += 256;
let byteStr = byte.toString(16);
// Ensure we have 2 chars in our byte, pad with 0
if (byteStr.length == 1) byteStr = '0'+byteStr;
signatureStr += byteStr;
}
Logger.log(signatureStr);
return signatureStr;
}
function logUrlFetch(url, opt_params) {
let params = opt_params || {};
params.muteHttpExceptions = true;
let request = UrlFetchApp.getRequest(url, params);
Logger.log('Request: >>> ' + JSON.stringify(request));
let response = UrlFetchApp.fetch(url, params);
Logger.log('Response Code: <<< ' + response.getResponseCode());
Logger.log('Response text: <<< ' + response.getContentText());
if (response.getResponseCode() >= 400) {
throw Error('Error in response: ' + response);
}
return response;
}
These are the logs I'm getting:
headers after the first request
log after the second request
I compared the headers in the Postman and my app multiple times and they are mostly the same with some differences. The UrlFetchApp.fetch adds a few headers to the request however I added them also in Postman and it still worked so I concluded these additional headers were not a problem. Also the UrlFetchApp.fetch sends a request method as 'post' (lower case) and the Postman uses all caps - 'POST'. The http method is a part of the Digest HA2 calculation, which is case sensitive. This was the only idea that I had for why my requests didn't work. I changed my app's method to lower case 'post' for the digest calculation and for the headers and this did not help.
Is there a way to send requests in the Google App Script other than UrlFetchApp.fetch?
Thanks a lot!