Helper for Axperiance

helper.script.js

 function httpGet(theUrl)
{
    var xmlHttp = new XMLHttpRequest();
    xmlHttp.open( "GET", theUrl, false ); // false for synchronous request
    xmlHttp.send( null );
    return xmlHttp.responseText;
}

function httpPost(theUrl,obj)
{
    console.log(obj)
    var xhr = new XMLHttpRequest();
    xhr.open("POST", theUrl, true);
    
    //Send the proper header information along with the request
    xhr.setRequestHeader("Content-type", "application/json");
    xhr.setRequestHeader("id", obj.id);
    xhr.setRequestHeader("user_id", obj.user_id);
    xhr.setRequestHeader("score", obj.score);
    xhr.setRequestHeader("cat_id", obj.cat_id);
    xhr.setRequestHeader("time_taken", obj.time_taken);
    xhr.setRequestHeader("no_of_questions",obj.no_of_questions);
    xhr.onreadystatechange = function() {//Call a function when the state changes.
        if(xhr.readyState == XMLHttpRequest.DONE && xhr.status == 200) {
            console.log("done");
        }
    }
    xhr.send(null); 
}

function httpPatch(theUrl,user_score)
{
    var xhr = new XMLHttpRequest();
    xhr.open("PATCH", theUrl, true);
    //Send the proper header information along with the request
    xhr.setRequestHeader("Content-type", "application/json");
    xhr.setRequestHeader("id", user_score.id);
    xhr.setRequestHeader("update_time", user_score.time_taken);
    xhr.setRequestHeader("update_score", user_score.score);
    xhr.setRequestHeader("update_no_of_question", user_score.no_of_questions);
    xhr.onreadystatechange = function() {//Call a function when the state changes.
        if(xhr.readyState == XMLHttpRequest.DONE && xhr.status == 200) {
            console.log("done");
        }
    }
    xhr.send(null); 
}

function httpGetOptions(quesId,theUrl = "https://arck9app.azurewebsites.net/api/getOptions")
{
    var xmlHttp = new XMLHttpRequest();
    xmlHttp.open( "GET", theUrl, false ); // false for synchronous request
    xmlHttp.setRequestHeader("quesid",quesId)
    xmlHttp.send( null );
    return xmlHttp.responseText;
}

function httpGetAsync(theUrl, callback)
{
    var xmlHttp = new XMLHttpRequest();
    xmlHttp.onreadystatechange = function() { 
        if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
            callback(xmlHttp.responseText);
    }
    xmlHttp.open("GET", theUrl, true); // true for asynchronous 
    xmlHttp.send(null);
}

function httpPostAsync(theUrl,obj,callback)
{
    var xhr = new XMLHttpRequest();
    xhr.open("POST", theUrl, true);
    
    //Send the proper header information along with the request
    xhr.setRequestHeader("Content-type", "application/json");
    
    xhr.onreadystatechange = function() {//Call a function when the state changes.
        if(xhr.readyState == XMLHttpRequest.DONE && xhr.status == 200) {
            callback(xhr.responseText);
        }
        else if(xhr.status == 409){
            callback(xhr.responseText);
        }
    }
    xhr.send(JSON.stringify(obj)); 
}

function str_pad_left(string,pad,length) {
    return (new Array(length+1).join(pad)+string).slice(-length);
}


/**
 * Getting Data from the server
 * It is a not a feasible way to do it. But it is the one of the best/easiest form
 */
function getDataFromServer()
{
    httpGetAsync("https://arck9app.azurewebsites.net/api/getQuestions",function(data)
    {
        questions = shuffle(JSON.parse(data));
        httpGetAsync("https://arck9app.azurewebsites.net/api/getOptions",function(data1)
        {
            options = shuffle(JSON.parse(data1));
            httpGetAsync("https://arck9app.azurewebsites.net/api/getCorrectOptions",function(data2)
            {
                correctAnswer = JSON.parse(data2);
                startQuiz();
            });
        });
    });
}

/**
 * 
 * @param {AnyArray} array
 * This method is stuffle the array such that questions and options are not same for all the users
 */
function shuffle(array) {
    var currentIndex = array.length, temporaryValue, randomIndex;
  
    // While there remain elements to shuffle...
    while (0 !== currentIndex) {
  
      // Pick a remaining element...
      randomIndex = Math.floor(Math.random() * currentIndex);
      currentIndex -= 1;
  
      // And swap it with the current element.
      temporaryValue = array[currentIndex];
      array[currentIndex] = array[randomIndex];
      array[randomIndex] = temporaryValue;
    }
  
    return array;
  }