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How to solve the task called 'Fast and Furious' from 'Break In 2017' challenge in C#?

I try to solve the task called Fast and Furious from Break In 2017 challenge.
The task is simple. Need to HTTP post back the result of a math expression contained in a HTML page. It can be achieved by this python script:
import requests
import re
url = 'https://felicity.iiit.ac.in/contest/extra/fastandfurious/'
s = requests.Session()
r = s.get(url)
print(r.text)
m = re.search('\(.*\)', r.text)
while m:
ans = eval(m[0])
print(m[0] + ' -> ' + str(ans))
r = s.post(url, data={'ques_ans' : ans})
print(r.text)
if ('the_flag_is_' in r.text): break
m = re.search('\(.*\)', r.text)
I want to do the same in C#. I tried like this:
using System;
using System.Data;
using System.IO;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
class Program
{
static CookieContainer cookies = new CookieContainer();
static HttpWebRequest Create(string url)
{
var request = (HttpWebRequest)WebRequest.Create(url);
request.CookieContainer = cookies;
request.Accept = "*/*";
request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
request.UserAgent = "dummy";
return request;
}
static string Get(string url)
{
var request = Create(url);
request.Method = "GET";
using (var response = request.GetResponse())
using (var reader = new StreamReader(response.GetResponseStream()))
{
return reader.ReadToEnd();
}
}
static string Post(string url, string postData)
{
var request = Create(url);
request.Method = "POST";
var data = Encoding.UTF8.GetBytes(postData);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = data.Length;
using (var stream = request.GetRequestStream())
{
stream.Write(data, 0, data.Length);
}
using (var response = request.GetResponse())
using (var reader = new StreamReader(response.GetResponseStream()))
{
return reader.ReadToEnd();
}
}
static string Eval(string expression)
{
DataTable dt = new DataTable();
return dt.Compute(expression, "").ToString();
}
static void Main()
{
string url = "https://felicity.iiit.ac.in/contest/extra/fastandfurious";
string text = Get(url);
Console.WriteLine(text);
var m = Regex.Match(text, #"\(.*\)");
while (m.Success)
{
var ans = Eval(m.Value);
Console.WriteLine(m.Value + " -> " + ans);
text = Post(url, "ques_ans=" + ans);
Console.WriteLine(text);
if (text.Contains("the_flag_is_")) break;
m = Regex.Match(text, #"\(.*\)");
}
}
}
But it does not work, because I always get back the 'Level 1' question. I used HttpWebRequest.CookieContainer property to reuse the cookies across different requests to keep up a session.
I don't know what is the problem. Maybe the session doesn't work.
Or perhaps HttpWebRequest is too slow to post back the result in time.
How to solve this automation task in C#?

Your code isn't handling being redirected. Watching the traffic we can see that this particular server would like your requests to /fastandfurious to end with a trailing slash. so change '../fastandfurious' to '../fastandfurious/' and that will fix it.

how to connect api django 1.10 with c#

I'm trying to connect Django API with c # but when I connect I face a problem in C#.
Django here I use as a server API and C# as a client.
Errors in C# are "CSRF is missing or incorrect".
using System;
using System.Net;
using System.IO;
using System.Text;
using System.Collections.Generic;
using System.Net.Http;
using System.Collections.Specialized;
using System.Text.RegularExpressions;
namespace ConsoleApplication1
{
class Program
{
private static string json;
public static string url { get; private set; }
static void Main(string[] args)
{
/*
try
{
CookieContainer container = new CookieContainer();
HttpWebRequest request1 = (HttpWebRequest)WebRequest.Create("http://127.0.0.1/api/");
request1.Proxy = null;
request1.CookieContainer = container;
using (HttpWebResponse response1 = (HttpWebResponse)request1.GetResponse())
{
foreach (Cookie cookie1 in response1.Cookies)
{
//Console.WriteLine(response.IsSuccessStatusCode);
var csrf = cookie1.Value;
Console.WriteLine(csrf);
Console.WriteLine("name=" + cookie1.Name);
Console.WriteLine();
Console.Write((int)response1.StatusCode);
//PostRespone("http://localhost/api/multiplyfunction/");
}
}
}
catch (WebException e)
{
Console.WriteLine(e.Status);
}
/* HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://localhost/api/");
request.CookieContainer = Cookie; // use the global cookie variable
string postData = "100";
byte[] data = Encoding.UTF8.GetBytes(postData);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded; charset=utf-8";
request.ContentLength = data.Length;
using (Stream stream = request.GetRequestStream())
{
stream.Write(data, 0, data.Length);
}
WebResponse response = (HttpWebResponse)request.GetResponse();
string responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();*/
WebClient csrfmiddlewaretoken = new WebClient();
CookieContainer cookieJar = new CookieContainer();
var request1 = (HttpWebRequest)HttpWebRequest.Create("http://localhost/api/");
request1.CookieContainer = cookieJar;
var response1 = request1.GetResponse();
string baseSiteString = csrfmiddlewaretoken.DownloadString("http://localhost/api/");
// string csrfToken = Regex.Match(baseSiteString, "<meta name=\"csrf-token\" content=\"(.*?)\" />").Groups[1].Value;
// wc.Headers.Add("X-CSRF-Token", csrfToken);
csrfmiddlewaretoken.Headers.Add("X-Requested-With", "XMLHttpRequest");
using (HttpWebResponse response2 = (HttpWebResponse)request1.GetResponse())
{
foreach (Cookie cookie1 in response2.Cookies)
{
//string cookie = csrfmiddlewaretoken.ResponseHeaders[HttpResponseHeader.SetCookie];//(response as HttpWebResponse).Headers[HttpResponseHeader.SetCookie];
Console.WriteLine(baseSiteString);
//Console.WriteLine("CSRF Token: {0}", csrfToken);
//Console.WriteLine("Cookie: {0}", cookie);
//
csrfmiddlewaretoken.Headers.Add(HttpRequestHeader.ContentType, "application/json; charset=utf-8");
//wc.Headers.Add(HttpRequestHeader.Accept, "application/json, text/javascript, */*; q=0.01");
var csrf1 = cookie1.Value;
string ARG1 = ("100");
string ARG2 = ("5");
string ARG = ("ARG");
string csrfmiddlewaretoken1 =cookie1.Name +"="+cookie1.Value;
csrfmiddlewaretoken.Headers.Add(HttpRequestHeader.Cookie, csrfmiddlewaretoken1);
//string csrf = string.Join(cookie, ARG1, ARG2);
//string dataString =cookie;
// string dataString = #"{""user"":{""email"":"""+uEmail+#""",""password"":"""+uPassword+#"""}}";
string dataString = "{\"ARG1\": \"100\", \"ARG2\": \"5\"}";
// string dataString = "csrftokenmiddlewaretoken="+csrfmiddlewaretoken;
//dataString += "&ARG1=10";
//dataString += "&ARG2=10";
byte[] dataBytes = Encoding.ASCII.GetBytes(dataString);
//byte[] respon2 = csrfmiddlewaretoken.DownloadData(new Uri("http://localhost/api/statusfunction/"));
WebRequest request = WebRequest.Create("http://localhost/api/statusfunction/?ARG");
// Get the response.
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
// Get the stream containing content returned by the server.
Stream dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd();
// Display the content.
Console.WriteLine(responseFromServer);
byte[] responseBytes = csrfmiddlewaretoken.UploadData(new Uri("http://localhost/api/multiplyfunction/"), "POST", dataBytes);
string responseString = Encoding.UTF8.GetString(responseBytes);
Console.WriteLine(responseString);
// byte[] res = csrfmiddlewaretoken.UploadFile("http://localhost/api/multiplyfunction/", #"ARG1:100");
// Console.WriteLine(result);
Console.WriteLine("value=" + cookie1.Value);
Console.WriteLine("name=" + cookie1.Name);
Console.WriteLine();
Console.Write((int)response2.StatusCode);
// PostRespone("http://localhost/api/multiplyfunction/");
}
}
}
}
}

Do you accept POST requests in your Django view? If yes, you should use #csrf_exempt decorator for the view that handles POST requests. The other option is to provide CSRF token from C# side.

Automatic add text on textbox when I open one site

So, i'm tring to put one information on one textbox, in more special textbox, CNPJ of one site:
http://www.receita.fazenda.gov.br/pessoajuridica/cnpj/cnpjreva/cnpjreva_solicitacao.asp
but I'm not getting... so, what I have tried... I have tried to put the cnpj value on the final of link, like this:
http://www.receita.fazenda.gov.br/pessoajuridica/cnpj/cnpjreva/cnpjreva_solicitacao.asp?cnpj=00495835000160
but, the site no put the value on the text box...
How I can make to enter with with the cnpj value on the site ( whiout digit on the site, just in the link... )
And, In C# I have tried this:
using System;
using System.IO;
using System.Net;
using System.Text;
namespace ReceitaFederal
{
class Program
{
static void Main(string[] args)
{
try
{
WebRequest request = WebRequest.Create("http://www.receita.fazenda.gov.br/pessoajuridica/cnpj/cnpjreva/cnpjreva_solicitacao.asp");
string strPost = "cnpj=00495835000160";
request.Method = "POST";
request.ContentLength = strPost.Length;
request.ContentType = "application/x-www-form-urlencoded";
StreamWriter writer = new StreamWriter(request.GetRequestStream());
writer.Write(strPost);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
reader.Close();
dataStream.Close();
response.Close();
Console.WriteLine(responseFromServer);
}
catch (Exception exec)
{
Console.WriteLine(exec.GetType() + "" + exec.Message);
}
}
}
}

Solved!!! First add this cookie container:
using System;
using System.Net;
namespace ConsultaCNPJ
{
public class CookieAwareWebClient : WebClient
{
private CookieContainer _mContainer;
public void SetCookieContainer(CookieContainer container)
{
_mContainer = container;
}
protected override WebRequest GetWebRequest(Uri address)
{
WebRequest request = base.GetWebRequest(address);
var webRequest = request as HttpWebRequest;
if (webRequest != null)
{
webRequest.CookieContainer = _mContainer;
webRequest.KeepAlive = true;
webRequest.ProtocolVersion = HttpVersion.Version10;
}
return request;
}
}
}
Then edit you code to this:
using System;
using System.Drawing;
using System.IO;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
namespace ConsultaCNPJ
{
public class ConsultaCNPJBroker
{
private readonly CookieContainer _cookies = new CookieContainer();
public String DominioReceitaFederal = "http://www.receita.fazenda.gov.br";
public String GetDataReceitaFederal = "/pessoajuridica/cnpj/cnpjreva/cnpjreva_solicitacao2.asp";
public String PostDataReceitaFederal = "/pessoajuridica/cnpj/cnpjreva/valida.asp";
private String _viewState;
public Bitmap GetCaptcha()
{
const string strViewState = "<input type=hidden id=viewstate name=viewstate value='";
const string strImagemCaptcha = "<img border='0' id='imgcaptcha' alt='Imagem com os caracteres anti robô' src='";
String htmlResult;
using (var wc = new CookieAwareWebClient())
{
wc.SetCookieContainer(_cookies);
wc.Headers[HttpRequestHeader.UserAgent] = "Mozilla/4.0 (compatible; Synapse)";
wc.Headers[HttpRequestHeader.KeepAlive] = "300";
htmlResult = wc.DownloadString(DominioReceitaFederal + GetDataReceitaFederal);
}
if (htmlResult.Length > 0)
{
_viewState = htmlResult;
int posString = _viewState.IndexOf(strViewState, StringComparison.Ordinal);
_viewState = _viewState.Substring(posString + strViewState.Length);
posString = _viewState.IndexOf("'>", StringComparison.Ordinal);
_viewState = _viewState.Substring(0, posString);
String urlImagemCaptcha = htmlResult;
posString = urlImagemCaptcha.IndexOf(strImagemCaptcha, StringComparison.Ordinal);
urlImagemCaptcha = urlImagemCaptcha.Substring(posString + strImagemCaptcha.Length);
posString = urlImagemCaptcha.IndexOf("'>", StringComparison.Ordinal);
urlImagemCaptcha = urlImagemCaptcha.Substring(0, posString);
urlImagemCaptcha = urlImagemCaptcha.Replace("amp;", "");
if (urlImagemCaptcha.Length > 0)
{
var wc2 = new CookieAwareWebClient();
wc2.SetCookieContainer(_cookies);
wc2.Headers[HttpRequestHeader.UserAgent] = "Mozilla/4.0 (compatible; Synapse)";
wc2.Headers[HttpRequestHeader.KeepAlive] = "300";
byte[] data = wc2.DownloadData(DominioReceitaFederal + urlImagemCaptcha);
return new Bitmap(
new MemoryStream(data));
}
return null;
}
_viewState = "";
return null;
}
public Stream Consulta(string aCNPJ, string aCaptcha, bool removerEspacosDuplos)
{
var request = (HttpWebRequest) WebRequest.Create(DominioReceitaFederal + PostDataReceitaFederal);
request.ProtocolVersion = HttpVersion.Version10;
request.CookieContainer = _cookies;
request.Method = "POST";
string fviewstate = _viewState;
fviewstate = Uri.EscapeDataString((fviewstate));
string postData = "";
postData = postData + "origem=comprovante&";
postData = postData + "viewstate=" + fviewstate + "&";
postData = postData + "cnpj=" + new Regex(#"[^\d]").Replace(aCNPJ, string.Empty) + "&";
postData = postData + "captcha=" + aCaptcha + "&";
postData = postData + "captchaAudio=&";
postData = postData + "submit1=Consultar&";
postData = postData + "search_type=cnpj";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;
Stream dataStream = request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
dataStream.Close();
WebResponse response = request.GetResponse();
return response.GetResponseStream();
}
}
}
That's it!
Special thanks to my great friend CunhaW!
Usage:
First create a form with a PictureBox and a TextBox and the broker for captcha like this
private readonly ConsultaCNPJBroker _broker = new ConsultaCNPJBroker();
this.ImgCaptcha = new System.Windows.Forms.PictureBox();
this.TbxCaptcha = new System.Windows.Forms.TextBox();
Then use like 2-Steps query, first get the Captcha then do the Query with the captcha
private void UpdateCaptcha()
{
ImgCaptcha.Image = _broker.GetCaptcha();
TbxCaptcha.Text = string.Empty;
}
A user interaction is need here to solve the captcha and fill the textbox and finally
private void BtnExecute_OnClick(object sender, EventArgs e)
{
var pessoaJuridica = _broker.Consulta(TbxCNPJ.Text, TbxCaptcha.Text, true);
// here you can see props like pessoaJuridica.CNPJ
}

Maybe this help you, it's not working yet... but almost there...
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Web;
using System.Windows.Forms;
namespace LeituraWeb
{
public partial class Form1 : Form
{
String viewState;
public String Dominio_ReceitaFederal = "http://www.receita.fazenda.gov.br/";
public String GetData_ReceitaFederal = "pessoajuridica/cnpj/cnpjreva/cnpjreva_solicitacao2.asp";
public String PostData_ReceitaFederal = "pessoajuridica/cnpj/cnpjreva/valida.asp";
public Form1()
{
InitializeComponent();
}
private void btnGo_Click(object sender, EventArgs e)
{
int PosString;
String StrViewState = "<input type=hidden id=viewstate name=viewstate value='";
String StrImagemCaptcha = "<img border='0' id='imgcaptcha' alt='Imagem com os caracteres anti robô' src='";
String UrlImagemCaptcha = "";
String HtmlResult = "";
using (WebClient wc = new WebClient()){
wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
HtmlResult = wc.DownloadString(Dominio_ReceitaFederal + GetData_ReceitaFederal);
}
if (HtmlResult.Length > 0)
{
viewState = HtmlResult;
// executando um crop do viewstate para utilizar no post
PosString = viewState.IndexOf(StrViewState);
viewState = viewState.Substring(PosString + StrViewState.Length);
PosString = viewState.IndexOf("'>");
viewState = viewState.Substring(0, PosString);
//executando um crop na url da imagem
UrlImagemCaptcha = HtmlResult;
PosString = UrlImagemCaptcha.IndexOf(StrImagemCaptcha);
UrlImagemCaptcha = UrlImagemCaptcha.Substring(PosString + StrImagemCaptcha.Length);
PosString = UrlImagemCaptcha.IndexOf("'>");
UrlImagemCaptcha = UrlImagemCaptcha.Substring(0, PosString);
UrlImagemCaptcha = UrlImagemCaptcha.Replace("amp;", "");
// populando a imagem do captcha dentro de um picturebox
if (UrlImagemCaptcha.Length > 0)
pictureBox1.Image = new System.Drawing.Bitmap(new System.IO.MemoryStream(new System.Net.WebClient().DownloadData(Dominio_ReceitaFederal + UrlImagemCaptcha)));
}
else
{
viewState = "";
}
}
private void button1_Click(object sender, EventArgs e)
{
WebRequest request = WebRequest.Create(Dominio_ReceitaFederal + PostData_ReceitaFederal);
// Formatando o ViewState Recebido
string fviewstate = viewState;
fviewstate = System.Uri.EscapeDataString(System.Uri.UnescapeDataString(fviewstate));
// inserindo os campos a serem postados
string postData = "";
postData = postData + "origem=comprovante&";
postData = postData + "viewstate=" + fviewstate + "&";
postData = postData + "cnpj=00000000000000&";
postData = postData + "captcha=000000&";
postData = postData + "captchaAudio=&";
postData = postData + "submit1=Consultar&";
postData = postData + "search_type=cnpj";
// montando a requisicao
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;
Stream dataStream = request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
dataStream.Close();
WebResponse response = request.GetResponse();
dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
// ---------- erro aqui !!!
// retorno da sefaz ---- sempre retorna -- Parametros Inválidos
Console.WriteLine(responseFromServer);
reader.Close();
dataStream.Close();
response.Close();
}
}
}

You have to make sure the target site supports the kind of request you are trying to do.
If not, you are out of luck. Keep in mind that the web app implementation is the one who dictates the rules, not you.
Additionally, it looks like you are trying to obtain information from a Brazilian government site. Usually, this type of sites have mechanisms to prevent what you are trying to achieve, such as captchas and domain validation.
The good news is that, also usually, government sites publish rules and manuals on how to access public webservices. However, you also usually need permission for that.

The page uses frames:
<frame name="top" scrolling="no" frameborder="0" marginheight="0" noresize="true" target="contents" src="cabecalho.htm" marginwidth="0" marginheight="0">
<frame frameborder="0" name="main" SRC="cnpjreva_solicitacao2.asp" scrolling="auto" noresize="false" marginheight="0" marginwidth="0">
The main frame contains the page cnpjreva_solicitacao2.asp, so calling http://www.receita.fazenda.gov.br/pessoajuridica/cnpj/cnpjreva/cnpjreva_solicitacao2.asp?cnpj=00495835000160 (see the 2 in the page file name) will show you the content of the main frame with the CNPJ filled as passed by the parameter.

I say instead of crafting the resulting code,
you could inject javascript.
e.g.
open the page you posted
http://www.receita.fazenda.gov.br/pessoajuridica/cnpj/cnpjreva/cnpjreva_solicitacao.asp
open JS Console and type the following:
document.getElementsByName("main")[0].contentDocument.getElementsByName("cnpj")[0].value = "MyNewValue"
Notice, the form is within a frame element, so you need to get the frame element and then the input element.
You can do the same via the Web Browser API.
Good Luck with solving the CAPTCHA

calling google Url Shortner API in C#

I want to call the google url shortner API from my C# Console Application, the request I try to implement is:
POST https://www.googleapis.com/urlshortener/v1/url
Content-Type: application/json
{"longUrl": "http://www.google.com/"}
When I try to use this code:
using System.Net;
using System.Net.Http;
using System.IO;
and the main method is:
static void Main(string[] args)
{
string s = "http://www.google.com/";
var client = new HttpClient();
// Create the HttpContent for the form to be posted.
var requestContent = new FormUrlEncodedContent(new[] {new KeyValuePair<string, string>("longUrl", s),});
// Get the response.
HttpResponseMessage response = client.Post("https://www.googleapis.com/urlshortener/v1/url",requestContent);
// Get the response content.
HttpContent responseContent = response.Content;
// Get the stream of the content.
using (var reader = new StreamReader(responseContent.ContentReadStream))
{
// Write the output.
s = reader.ReadToEnd();
Console.WriteLine(s);
}
Console.Read();
}
I get the error code 400: This API does not support parsing form-encoded input.
I don't know how to fix this.

you can check the code below (made use of System.Net).
You should notice that the contenttype must be specfied, and must be "application/json"; and also the string to be send must be in json format.
using System;
using System.Net;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
var httpWebRequest = (HttpWebRequest)WebRequest.Create("https://www.googleapis.com/urlshortener/v1/url");
httpWebRequest.ContentType = "application/json";
httpWebRequest.Method = "POST";
using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
string json = "{\"longUrl\":\"http://www.google.com/\"}";
Console.WriteLine(json);
streamWriter.Write(json);
}
var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
var responseText = streamReader.ReadToEnd();
Console.WriteLine(responseText);
}
}
}
}

Google has a NuGet package for using the Urlshortener API. Details can be found here.
Based on this example you would implement it as such:
using System;
using System.Net;
using System.Net.Http;
using Google.Apis.Services;
using Google.Apis.Urlshortener.v1;
using Google.Apis.Urlshortener.v1.Data;
using Google.Apis.Http;
namespace ConsoleTestBed
{
class Program
{
private const string ApiKey = "YourAPIKey";
static void Main(string[] args)
{
var initializer = new BaseClientService.Initializer
{
ApiKey = ApiKey,
//HttpClientFactory = new ProxySupportedHttpClientFactory()
};
var service = new UrlshortenerService(initializer);
var longUrl = "http://wwww.google.com/";
var response = service.Url.Insert(new Url { LongUrl = longUrl }).Execute();
Console.WriteLine($"Short URL: {response.Id}");
Console.ReadKey();
}
}
}
If you are behind a firewall you may need to use a proxy. Below is an implementation of the ProxySupportedHttpClientFactory, which is commented out in the sample above. Credit for this goes to this blog post.
class ProxySupportedHttpClientFactory : HttpClientFactory
{
private static readonly Uri ProxyAddress
= new UriBuilder("http", "YourProxyIP", 80).Uri;
private static readonly NetworkCredential ProxyCredentials
= new NetworkCredential("user", "password", "domain");
protected override HttpMessageHandler CreateHandler(CreateHttpClientArgs args)
{
return new WebRequestHandler
{
UseProxy = true,
UseCookies = false,
Proxy = new WebProxy(ProxyAddress, false, null, ProxyCredentials)
};
}
}

How about changing
var requestContent = new FormUrlEncodedContent(new[]
{new KeyValuePair<string, string>("longUrl", s),});
to
var requestContent = new StringContent("{\"longUrl\": \" + s + \"}");

Following is my working code. May be its helpful for you.
private const string key = "xxxxxInsertGoogleAPIKeyHerexxxxxxxxxx";
public string urlShorter(string url)
{
string finalURL = "";
string post = "{\"longUrl\": \"" + url + "\"}";
string shortUrl = url;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://www.googleapis.com/urlshortener/v1/url?key=" + key);
try
{
request.ServicePoint.Expect100Continue = false;
request.Method = "POST";
request.ContentLength = post.Length;
request.ContentType = "application/json";
request.Headers.Add("Cache-Control", "no-cache");
using (Stream requestStream = request.GetRequestStream())
{
byte[] postBuffer = Encoding.ASCII.GetBytes(post);
requestStream.Write(postBuffer, 0, postBuffer.Length);
}
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
{
using (Stream responseStream = response.GetResponseStream())
{
using (StreamReader responseReader = new StreamReader(responseStream))
{
string json = responseReader.ReadToEnd();
finalURL = Regex.Match(json, #"""id"": ?""(?.+)""").Groups["id"].Value;
}
}
}
}
catch (Exception ex)
{
// if Google's URL Shortener is down...
System.Diagnostics.Debug.WriteLine(ex.Message);
System.Diagnostics.Debug.WriteLine(ex.StackTrace);
}
return finalURL;
}

Uploading images to Imgur.com using C#

I just recieve my unique developer API key from Imgur and I'm aching to start cracking on this baby.
First a simple test to kick things off. How can I upload an image using C#? I found this using Python:
#!/usr/bin/python
import pycurl
c = pycurl.Curl()
values = [
("key", "YOUR_API_KEY"),
("image", (c.FORM_FILE, "file.png"))]
# OR: ("image", "http://example.com/example.jpg"))]
# OR: ("image", "BASE64_ENCODED_STRING"))]
c.setopt(c.URL, "http://imgur.com/api/upload.xml")
c.setopt(c.HTTPPOST, values)
c.perform()
c.close()

looks like the site uses HTTP Post to upload images. Take a look at the HTTPWebRequest class and using it to POST to a URL: Posting data with HTTPRequest.

The Imgur API now provide a complete c# example :
using System;
using System.IO;
using System.Net;
using System.Text;
namespace ImgurExample
{
class Program
{
static void Main(string[] args)
{
PostToImgur(#"C:\Users\ashwin\Desktop\image.jpg", IMGUR_ANONYMOUS_API_KEY);
}
public static void PostToImgur(string imagFilePath, string apiKey)
{
byte[] imageData;
FileStream fileStream = File.OpenRead(imagFilePath);
imageData = new byte[fileStream.Length];
fileStream.Read(imageData, 0, imageData.Length);
fileStream.Close();
string uploadRequestString = "image=" + Uri.EscapeDataString(System.Convert.ToBase64String(imageData)) + "&key=" + apiKey;
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create("http://api.imgur.com/2/upload");
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.ServicePoint.Expect100Continue = false;
StreamWriter streamWriter = new StreamWriter(webRequest.GetRequestStream());
streamWriter.Write(uploadRequestString);
streamWriter.Close();
WebResponse response = webRequest.GetResponse();
Stream responseStream = response.GetResponseStream();
StreamReader responseReader = new StreamReader(responseStream);
string responseString = responseReader.ReadToEnd();
}
}
}

Why don't you use the NuGet for this: called Imgur.API and for upload
you would have a method like this:
/*
The refresh token and all the values represented by constans are given when you allow the application in your imgur panel on the response url
*/
public OAuth2Token CreateToken()
{
var token = new OAuth2Token(TOKEN_ACCESS, REFRESH_TOKEN, TOKEN_TYPE, ID_ACCOUNT, IMGUR_USER_ACCOUNT, int.Parse(EXPIRES_IN));
return token;
}
//Use it only if your token is expired
public Task<IOAuth2Token> RefreshToken()
{
var client = new ImgurClient(CLIENT_ID, CLIENT_SECRET);
var endpoint= new OAuth2Endpoint(client);
var token = endpoint.GetTokenByRefreshTokenAsync(REFRESH_TOKEN);
return token;
}
public async Task UploadImage()
{
try
{
var client = new ImgurClient(CLIENT_ID, CLIENT_SECRET, CreateToken());
var endpoint = new ImageEndpoint(client);
IImage image;
//Here you have to link your image location
using (var fs = new FileStream(#"IMAGE_LOCATION", FileMode.Open))
{
image = await endpoint.UploadImageStreamAsync(fs);
}
Debug.Write("Image uploaded. Image Url: " + image.Link);
}
catch (ImgurException imgurEx)
{
Debug.Write("Error uploading the image to Imgur");
Debug.Write(imgurEx.Message);
}
}
Also you can find all the reference here: Imgur.API NuGet