Embed Token Generation

/*
  Required modules for cryptography, URL parsing, and HTTP requests.
  Make sure you have 'express' installed: npm install express
*/
const crypto = require('crypto');
const https = require('https');
const http = require('http');
const url = require('url');

app.post('/tokenGeneration', function () {
   
   // Details needed for generating the embed token
    var serverUrl = "< Bold BI server URL >";
    var siteIdentifier = "< Bold BI server Site Identifier >";
    var dashboardId = "< Dashboard Id >";
    var useremail = "< Bold BI server user Email >";
    var embedSecret = "< Embed Secret key >";

    // Making the BoldBI server API endpoint.
    var serverApiUrl = serverUrl + "/api/" + siteIdentifier;

   // Adding the query string with nonce, dashboard ID and user email.
    var queryString = "embed_nonce=" + crypto.randomUUID();
    queryString += "&embed_dashboard_id=" + dashboardId;
    queryString += "embed_user_email=" + useremail;
    
    // Signing the querystring with the embed secret key.
    var embedSignature = "&embed_signature=" + GetSignatureUrl(queryString,embedSecret);
    var embedDetailsUrl = "/embed/authorize?" + queryString + embedSignature;

   // Send the request to Bold BI server and returns the embed token.
   var serverProtocol = url.parse(serverApiUrl).protocol == 'https:' ? https : http;
   serverProtocol.get(serverApiUrl + embedDetailsUrl, function (resultContent) {
    let str = '';
    resultContent.on('data', function (chunk) {
        str += chunk;
    });
    resultContent.on('end', function () {
            const resultJson = JSON.parse(str);
            // Check if the response is valid and contains the access token
            if (resultJson && resultJson.ApiStatus && resultJson.Data && resultJson.Data.access_token) {
                response.json({ access_token: resultJson.Data.access_token });
            }
        });
    });

})

  // This function will make the queryString to cryptographically signed using the Embed Secret Key. This signature ensures the integrity and authenticity of the request.

  function GetSignatureUrl(queryString,embedSecret)
  {
    var keyBytes = Buffer.from(embedSecret);
    var hmac = crypto.createHmac('sha256', keyBytes);
    data = hmac.update(queryString);
    gen_hmac= data.digest().toString('base64');

   return gen_hmac;
  }