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Converting XMLHttpRequest to C#

I've now spent some time trying to get the JavaScript below working in my API (c#).
I run perfectly in JavaScript, but I get access denied as a response in my c# code.
JS :
var xhr = new XMLHttpRequest();
xhr.addEventListener("readystatechange", function () {
if (this.readyState === 4) {
document.getElementById('KundeListing').innerHTML = this.responseText;
console.log(this.responseText);
}
});
xhr.open("GET", "https://plus.dnb.com/v1/search/typeahead?searchTerm=Wal&countryISOAlpha2Code=US");
xhr.setRequestHeader("Authorization", "Bearer " + Token);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.withCredentials = false;
xhr.send();
But When trying usingRestSharp; I am getting errors
'You are not currently authorized to access this product'
public string Get(string Token)
{
var client = new RestSharp.RestClient("https://plus.dnb.com/v1/search/typeahead?searchTerm=Wal&countryISOAlpha2Code=US");
var request = new RestRequest(Method.GET)
{
UseDefaultCredentials = true
};
request.AddHeader("accept", "application/json");
request.AddHeader("authorization", "Bearer " + Token);
IRestResponse response = client.Execute(request);
return response.ToString();
}

JavaScript; Getting the content of the file into array chunks

I am working on the Google Drive API to get a document from the google drive, and then I’m trying to get the document’s contents into chunks of blocks so I can encrypt block-by-block. Can you help me figure out a way of achieving that? This is what I have tried.
function getDocumentContents() {
var accessToken = user.getAuthResponse().access_token;
var xhr = new XMLHttpRequest();
xhr.open('GET', 'https://www.googleapis.com/drive/v3/files/' + fileId
+ '?alt=media');
xhr.setRequestHeader('Authorization', 'Bearer ' + accessToken);
xhr.onload = function() {
modelContent = xhr.responseText;
extractKey(xhr.responseText);
};
xhr.onerror = function() {
alert('error');
};
xhr.send();
var chunkSize=512*512;
var fileSize=file.size;
var chunks=Math.ceil(xhr.size/chunkSize,chunkSize);
var chunk=0;
console.log('chunks...',chunks);
while( chunk <= chunks)
var offset=chunk*chunkSize;
console.log('current chunk..', chunk);
chunk.send();
console.log('offset',offset);
console.log(xhr.slice(offset,offset+chunkSize));
}
Thanks

Can't send XMLHttpRequest/XDomainRequest in IE8, fails on xhr.send()

I've looked through answers but can't seem to find one that fixes this particular problem. Also a similar question is still unanswered.
I am using IE8 to send a XMLHttpRequest but it never gets sent. IE8 supports XMLHttpRequest objects, so why isn't it sending? (I can't use jQuery for this.)
My code:
window.onload = function() {
// Create the HTTP object
var xmlhttp;
if (window.XMLHttpRequest) {
xmlhttp = new XMLHttpRequest();
} else {
alert("couldn't load data");
}
var dataUrl = "./data2.json";
alert("sending");
xmlhttp.open("GET", dataUrl, true);
alert("sent");
xmlhttp.onreadystatechange = function() {
//ready?
if (xmlhttp.readyState != 4)
return false;
//get status:
var status = xmlhttp.status;
//maybe not successful?
if (status != 200) {
alert("AJAX: server status " + status);
return false;
}
//Got result. All is good.
alert(xmlhttp.responseText);
return true;
}
xmlhttp.send(null);
}
The alert('sent'); never gets called, but alert('sending'); does. How can I make this xmlhttp request work?
Edit: I've updated my code to include XDomainRequest for IE8. This gets me past the xmlhttp.open part, but now I'm getting an "Unspecified error" on the xmlhttp.send part.
edited code (Note: I changed my variable name from xmlhttp to xhr.):
window.onload = function() {
// Create the HTTP object
var xhr;
if (window.XMLHttpRequest) {
xhr = new XMLHttpRequest();
} else {
alert("couldn't load data");
}
var dataUrl = "./data2.json";
alert("sending");
if ("withCredentials" in xhr) {
// XHR for Chrome/Firefox/Safari
xhr.open('get', dataUrl, true);
}else if (typeof XDomainRequest != "undefined") {
// XDomainRequest for IE.
xhr = new XDomainRequest();
xhr.open('get', dataUrl);
alert("opened");
} else{
alert('CORS not supported');
};
xhr.onprogress = function () { };
xhr.ontimeout = function () { };
xhr.onerror = function () { alert('error'); };
xhr.onload = function() {
alert(xhr.responseText);
}
setTimeout(function () {xhr.send();}, 0);
}
alert('error'); gets called.

Ajax - Function to check if url exists before send request

I am writing a function to grab a json file from a website/server and save it in local storage with the code:
function donators() {
var jsonURL = "http://mywebsite.com/donators.json";
var xhr = new XMLHttpRequest();
xhr.open("GET", jsonURL, true);
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
localDataStore.set("fb_donators", xhr.responseText);
}
};
xhr.send();
}
The above code works perfectly fine when the json file can be reached, but if my server goes down and the file cannot be reached my script halts at the line with xhr.send() with the error:
GET http://mywebsite.com/donators.json net::ERR_NAME_NOT_RESOLVED
Is there a way I can detect check if url can be reached before the send request to stop the send the request and allow the rest of my script to continue to run instead of getting halted at xhr.send()?
Thanks!

You can use a try block for this. It still requires the HTTP request, but it will fail gracefully and you can handle the error any way you'd like.
function donators() {
var jsonURL = "http://mywebsite.com/donators.json";
var xhr = new XMLHttpRequest();
xhr.open("GET", jsonURL, true);
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
localDataStore.set("fb_donators", xhr.responseText);
}
};
xhr.timeout = 5000;
xhr.ontimeout = function() {
alert( 'The operation timed out.' );
}
try { xhr.send(); } catch( err ) {
alert( 'Error getting data: ' + err.message );
}
}

Fetching a file from google drive and parsing it

I am able to fetch the contents of a zip file from google drive using javascript api. But i am not able to unzip the file. I am using JSZip (http://stuartk.com/jszip) to unzip. How do i achive this. Please help i am stuck on this from last 3 days.
gapi.client.load('drive', 'v2', function(){
var config = {
'client_id': '{!gApp.clientid__c}',
'scope': 'https://www.googleapis.com/auth/drive',
'immediate':true
};
gapi.auth.authorize(config, function() {
var accessToken = gapi.auth.getToken().access_token;
var xhr = new XMLHttpRequest();
xhr.open('GET', fileURL);
xhr.setRequestHeader('Authorization', 'Bearer ' + accessToken);
xhr.onload = function() {
//reponse :unzip the file here
var zipData = xhr.responseText;
var zip = new JSZip(zipData, {base64:false});
console.log(zip.files) //get an error undefined
};
xhr.onerror = function() {
alert('error');
};
xhr.send();
});
});