We Keep Coding

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.

Linked In API (auth token (oauth2)) c#.net

I wonder if someone can give me some pointers on using the linked in API. I thought I had it sussed but for some reason when trying to get the auth_token I just get http 400 Bad Request.
My code, simply is:
public string redirectUrl = URLTOREDIRECT;
public String apiKey = APIKEY;
public String apiSecret = APISECRET;
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
if (Request.QueryString["code"] != null)
{
VerifyAuthentication(Request.QueryString["code"]);
}
}
}
protected void Button1_Click(object sender, EventArgs e)
{
Response.Redirect("https://www.linkedin.com/uas/oauth2/authorization?response_type=code&client_id=apiKey&scope=rw_company_admin&state=DCEEFWF45453sdffef424&redirect_uri=" + HttpUtility.HtmlEncode(redirectUrl));
}
public String VerifyAuthentication(string code)
{
string authUrl = "https://www.linkedin.com/uas/oauth2/accessToken";
var sign = "grant_type=authorization_code" + "&code=" + code + "&redirect_uri=" + HttpUtility.HtmlEncode(redirectUrl) + "&client_id=" + _consumerkey + "&client_secret=" + _consumerSecret;
// var postData = String.Format("grant_type=authorization_code&code={0}&redirect_uri={1}&client_id={2}&client_secret={3}", code, HttpUtility.HtmlEncode(redirectUrl), apiKey, apiSecret);
HttpWebRequest webRequest = WebRequest.Create(authUrl + "?" + sign) as HttpWebRequest;
webRequest.Method = "POST";
//This "application/x-www-form-urlencoded"; line is important
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.ContentLength = sign.Length;
StreamWriter requestWriter = new StreamWriter(webRequest.GetRequestStream());
requestWriter.Write(sign);
requestWriter.Close();
StreamReader responseReader = new StreamReader(webRequest.GetResponse().GetResponseStream());
return responseReader.ReadToEnd().ToString() ;
}
The code is all in the same page for testing purposes and is the same page as the redirectUrl.
Really stumped, tried all variations.
First bit clearly works as I get directed to linked in to allow app. The second part getting the auth token fails.

After much head scratching, eureka moment - did not need to send the info in the request.
string authUrl = "https://www.linkedin.com/uas/oauth2/accessToken";
var sign = "grant_type=authorization_code&code=" + HttpUtility.UrlEncode(code) + "&redirect_uri=" + HttpUtility.HtmlEncode(redirectUrl) + "&client_id=" + apiKey + "&client_secret=" + apiSecret;
//byte[] byteArray = Encoding.UTF8.GetBytes(sign);
HttpWebRequest webRequest = WebRequest.Create(authUrl + "?" + sign) as HttpWebRequest;
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
Stream dataStream = webRequest.GetRequestStream();
String postData = String.Empty;
byte[] postArray = Encoding.ASCII.GetBytes(postData);
dataStream.Write(postArray, 0, postArray.Length);
dataStream.Close();
WebResponse response = webRequest.GetResponse();
dataStream = response.GetResponseStream();
StreamReader responseReader = new StreamReader(dataStream);
String returnVal = responseReader.ReadToEnd().ToString();
responseReader.Close();
dataStream.Close();
response.Close();
return returnVal;

I'm Using this code and it's working fine..... C# code ASP.NET :
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Web;
using System.Web.Script.Serialization;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace LI
{
public partial class WebForm3 : System.Web.UI.Page
{
public string redirectUrl = "http://localhost:64576/WebForm3";
public string TokenGlobe = "";
public String apiKey = "API_KEY";
public string retval = "";
public String apiSecret = "API_Secret";
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
if (Request.QueryString["code"] != null)
{
VerifyAuthentication(Request.QueryString["code"]);
}
}
}
protected void btnTwit_Click(object sender, EventArgs e)
{
var Address = "https://www.linkedin.com/oauth/v2/authorization?response_type=code&client_id=" + apiKey + "&redirect_uri=http://localhost:64576/WebForm3&state=987654321&scope=w_share";
using (var webClient = new WebClient())
{
webClient.Headers.Add("x-li-format", "json");
}
Response.Redirect(Address);
}
public String VerifyAuthentication(string code)
{
string authUrl = "https://www.linkedin.com/oauth/v2/accessToken";
var sign1 = "grant_type=authorization_code&code=" + code + "&redirect_uri=" + redirectUrl + "&client_id=" + apiKey + "&client_secret=" + apiSecret + "";
var sign = "grant_type=authorization_code&code=" + HttpUtility.UrlEncode(code) + "&redirect_uri=" + HttpUtility.HtmlEncode(redirectUrl) + "&client_id=" + apiKey + "&client_secret=" + apiSecret;
HttpWebRequest webRequest = System.Net.WebRequest.Create(authUrl + "?" + sign) as HttpWebRequest;
webRequest.Method = "POST";
webRequest.Host = "www.linkedin.com";
webRequest.ContentType = "application/x-www-form-urlencoded";
Stream dataStream = webRequest.GetRequestStream();
String postData = String.Empty;
byte[] postArray = Encoding.ASCII.GetBytes(postData);
dataStream.Write(postArray, 0, postArray.Length);
dataStream.Close();
WebResponse response = webRequest.GetResponse();
dataStream = response.GetResponseStream();
StreamReader responseReader = new StreamReader(dataStream);
String returnVal = responseReader.ReadToEnd().ToString();
responseReader.Close();
dataStream.Close();
response.Close();
var stri = redirectUrl;
retval = returnVal.ToString();
var objects = JsonConvert.DeserializeObject<Accountdsdsd>(retval);//JArray.Parse(retval);
TokenGlobe = objects.access_token;
var SentStatus = PostLinkedInNetworkUpdate(TokenGlobe, "Hello API"); //Share
return TokenGlobe;
// return responseReader.ReadToEnd().ToString();
}
private string linkedinSharesEndPoint = "https://api.linkedin.com//v1/people/~/shares?oauth2_access_token={0}&format=json";
private const string defaultUrl = "http://localhost:64576/WebForm3";
private const string defaultImageUrl = "http://opusleads.com/opusing/technology/technology%20(1).jpg"; //Image To Post
public bool PostLinkedInNetworkUpdate(string accessToken, string title, string submittedUrl = defaultUrl, string submittedImageUrl = defaultImageUrl)
{
var requestUrl = String.Format(linkedinSharesEndPoint, accessToken);
var message = new
{
comment = "Testing out the LinkedIn Share API with JSON",
content = new Dictionary<string, string>
{ { "title", title },
{ "submitted-url", submittedUrl },
{"submitted-image-url" , submittedImageUrl}
},
visibility = new
{
code = "anyone"
}
};
var requestJson = new JavaScriptSerializer().Serialize(message);
var client = new WebClient();
var requestHeaders = new NameValueCollection
{
{"Content-Type", "application/json" },
{"x-li-format", "json" }
};
client.Headers.Add(requestHeaders);
var responseJson = client.UploadString(requestUrl, "POST", requestJson);
var response = new JavaScriptSerializer().Deserialize<Dictionary<string, object>>(responseJson);
return response.ContainsKey("updateKey");
}
}
//Json Parsing
public class Accountdsdsd
{
public string access_token { get; set; }
public string expires_in { get; set; }
}
}

oauth/token returns empty body

I am encountering a problem getting the access_token in client application using oauth.
The returned response has empty body though in API I can see the response is not empty.
tokenresponse = {
"access_token":"[ACCESSTOKENVALUE]",
"token_type":"bearer",
"expires_in":"1200",
"refresh_token":"[REFRESHTOKENVALUE]",
"scope":"[SCOPEVALUE]"
}
The method from API that returns the token http://api.sample.com/OAuth/Token:
public ActionResult Token()
{
OutgoingWebResponse response =
this.AuthorizationServer.HandleTokenRequest(this.Request);
string tokenresponse = string.Format("Token({0})", response!=null?response.Body:""));
return response.AsActionResult();
}
The client method that requests the token is:
public string GetAuthorizationToken(string code)
{
string Url = ServerPath + "OAuth/Token";
string redirect_uri_encode = UrlEncode(ClientPath);
string param = string.Format("code={0}&client_id={1}&client_secret={2}&redirect_uri={3}&grant_type=authorization_code",code, ClientId, ClientSecret, redirect_uri_encode);
HttpWebRequest request = HttpWebRequest.Create(Url) as HttpWebRequest;
string result = null;
request.Method = "POST";
request.KeepAlive = true;
request.ContentType = "application/x-www-form-urlencoded";
request.Timeout = 10000;
request.Headers.Remove(HttpRequestHeader.Cookie);
var bs = Encoding.UTF8.GetBytes(param);
using (Stream reqStream = request.GetRequestStream())
{
reqStream.Write(bs, 0, bs.Length);
}
using (WebResponse response = request.GetResponse())
{
var sr = new StreamReader(response.GetResponseStream());
result = sr.ReadToEnd();
sr.Close();
}
if (!string.IsNullOrEmpty(result))
{
TokenData tokendata = JsonConvert.DeserializeObject<TokenData>(result);
return UpdateAuthorizotionFromToken(tokendata);
}
return null;
}
The result variable is empty.
Please let me know if you have any idea what could cause this. Initially I assumed is because of the cookies so I tried to remove them from request.
Thanks in advance.

Dear just create webclient using following code and you will get json info in tokeninfo.I used it and simply its working perfect.
WebClient client = new WebClient();
string postData = "client_id=" + ""
+ "&client_secret=" + ""
+ "&grant_type=password&username=" + "" //your username
+ "&password=" + "";//your password :)
string soundCloudTokenRes = "https://api.soundcloud.com/oauth2/token";
string tokenInfo = client.UploadString(soundCloudTokenRes, postData);
You can then use substring that contains only token from tokeninfo.
To upload tracks on sound cloud.
private void TestSoundCloudupload()
{
System.Net.ServicePointManager.Expect100Continue = false;
var request = WebRequest.Create("https://api.soundcloud.com/tracks") as HttpWebRequest;
//some default headers
request.Accept = "*/*";
request.Headers.Add("Accept-Charset", "ISO-8859-1,utf-8;q=0.7,*;q=0.3");
request.Headers.Add("Accept-Encoding", "gzip,deflate,sdch");
request.Headers.Add("Accept-Language", "en-US,en;q=0.8,ru;q=0.6");
//file array
var files = new UploadFile[] { new UploadFile(Server.MapPath("Downloads//0.mp3"), "track[asset_data]", "application/octet-stream") };
//other form data
var form = new NameValueCollection();
form.Add("track[title]", "Some title");
form.Add("track[sharing]", "public");
form.Add("oauth_token", "");
form.Add("format", "json");
form.Add("Filename", "0.mp3");
form.Add("Upload", "Submit Query");
try
{
using (var response = HttpUploadHelper.Upload(request, files, form))
{
using (var reader = new StreamReader(response.GetResponseStream()))
{
Response.Write(reader.ReadToEnd());
}
}
}
catch (Exception ex)
{
Response.Write(ex.ToString());
}
}

Keep login data alive after HTTP-request login

with a HTTP request I'm login into the page: https://secure.bodytel.com/de/mybodytel.html. After that I want to read the settings (https://secure.bodytel.com/de/mybodytel/settings.html). So here's my problem: I send a second request and the page tells me I'm not logged in anymore. When I debug things with fiddler I saw that I have two different cookie IDs. So, how can I keep the cookie alive? or send it with my request.
I already read this post: "http://stackoverflow.com/questions/11596378/getting-a-page-source-after-post-variables-have-been-sent" but it didn't helped me very much.
Here's my code:
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Forms;
using System.Net;
using System.IO;
using System.Web;
namespace BodytelConnection
{
/// <summary>
/// Interaktionslogik für MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
private void loginBtn_Click(object sender, RoutedEventArgs e)
{
#region username stuff
string benutzername = textBox_benutzername.ToString();
string passwort = textBox_passwort.ToString();
passwort = changeString(passwort);
benutzername = changeString(benutzername);
#endregion username stuff
CookieCollection cookies = new CookieCollection();
CookieContainer container = new CookieContainer();
#region login
HttpWebRequest getRequest = (HttpWebRequest)WebRequest.Create("https://secure.bodytel.com/de/mybodytel.html");
getRequest.Method = WebRequestMethods.Http.Post;
getRequest.AllowWriteStreamBuffering = true;
getRequest.AllowAutoRedirect = true;
getRequest.ContentType = "application/x-www-form-urlencoded";
byte[] byteArray = Encoding.ASCII.GetBytes("login=" + benutzername + "&password=" + passwort + "&step=login");
getRequest.ContentLength = byteArray.Length;
Stream newStream = getRequest.GetRequestStream();
newStream.Write(byteArray, 0, byteArray.Length);
newStream.Close();
HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
StreamReader sr = new StreamReader(getResponse.GetResponseStream());
// here im trying to save the cookie
container.Add(getResponse.Cookies);
getRequest.CookieContainer = container;
string source = sr.ReadToEnd();
// save the html
StreamWriter myWriter = File.CreateText(#"C:\Users\nicholas\Documents\Visual Studio 2010\Projects\BodytelConnection\BodytelConnection\bin\\Debug\test.txt");
myWriter.Write(source);
myWriter.Close();
#endregion login
//read the settings
#region readSettings
getRequest.Method = WebRequestMethods.Http.Get;
getRequest = (HttpWebRequest)WebRequest.Create("https://secure.bodytel.com/de/mybodytel/settings.html");
getRequest.AllowWriteStreamBuffering = true;
getResponse = (HttpWebResponse)getRequest.GetResponse();
sr = new StreamReader(getResponse.GetResponseStream());
source = sr.ReadToEnd();
StreamWriter myWriter2 = File.CreateText(#"C:\Users\nicholas\Documents\Visual Studio 2010\Projects\BodytelConnection\BodytelConnection\bin\\Debug\test2.txt");
myWriter2.Write(source);
myWriter2.Close();
getResponse.Close();
#endregion readSettings
}
private string changeString(string myString)
{
myString = myString.Replace("System.Windows.Controls.TextBox: ", "");
return myString;
}
}
}

You should be sending cookies with every request, otherwise server has no way of figuring out who is the user

I got it now. Thanks for your help Gaurav.
Here's the code:
private void loginBtn_Click(object sender, RoutedEventArgs e)
{
#region username stuff
string benutzername = textBox_benutzername.ToString();
string passwort = textBox_passwort.ToString();
passwort = changeString(passwort);
benutzername = changeString(benutzername);
#endregion username stuff
// get the first cookie
CookieContainer cookies = new CookieContainer();
CookieContainer cookieContainer = new CookieContainer();
HttpWebRequest sessionRequest = (HttpWebRequest)WebRequest.Create("http://www.bodytel.com/");
sessionRequest.CookieContainer = new CookieContainer();
cookies = sessionRequest.CookieContainer;
HttpWebResponse sessionResponse = (HttpWebResponse)sessionRequest.GetResponse();
sessionResponse.Close();
// login
HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create("https://secure.bodytel.com/de/mybodytel.html");
req.CookieContainer = cookieContainer;
req.Method = "POST";
req.ContentType = "application/x-www-form-urlencoded";
byte[] byteArray = Encoding.ASCII.GetBytes("login=" + benutzername + "&password=" + passwort + "&step=login");
req.ContentLength = byteArray.Length;
Stream newStream = req.GetRequestStream();
newStream.Write(byteArray, 0, byteArray.Length);
newStream.Close();
HttpWebResponse res = (HttpWebResponse)req.GetResponse();
// now connect to the other link
req = (HttpWebRequest)HttpWebRequest.Create("https://secure.bodytel.com/de/mybodytel/settings.html");
req.CookieContainer = cookieContainer;
req.Method = "GET";
res = (HttpWebResponse)req.GetResponse();
StreamReader sr = new StreamReader(res.GetResponseStream());
string source = sr.ReadToEnd();
StreamWriter myWriter = File.CreateText(#"C:\Users\nicholas\Documents\Visual Studio 2010\Projects\BodytelConnection\BodytelConnection\bin\\Debug\test.txt");
myWriter.Write(source);
myWriter.Close();
res.Close();
}

ArgumentOutOfRangeException was unhandled

On line 69 I am getting the error "ArgumentOutOfRangeException was unhandled".
/*
Please critique as I'm always looking for ways to improve my coding.
Usage Example:
MapleWebStart mws = new MapleWebStart("myusername", "mypassword");
mws.Start();
*/
using System;
using System.Diagnostics;
using System.IO;
using System.Net;
using System.Text;
using Microsoft.Win32;
public class MapleWebStart
{
private CookieContainer LoginCookie;
public MapleWebStart(string username, string password)
{
LoginCookie = new CookieContainer();
if (!Login(username, password))
throw new ArgumentException("Invalid Nexon username or password.");
}
public MapleWebStart(CookieContainer loginCookie)
{
LoginCookie = loginCookie;
}
private bool Login(string username, string password)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://maplestory.nexon.net/Controls/Passport.aspx");
request.Method = "POST";
string postData = "__VIEWSTATE=%2FwEPDwULLTE5NjM3MjM3MDcPZBYCAgMPZBYEAgUPFgIeB1Zpc2libGVoZAIHDxYCHwBoZGSVGoua1TAiCeQWNk%2BdqOF%2FXtq%2BmA%3D%3D&tbID=" + username + "&" + "tbPass=" + password;
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
request.CookieContainer = LoginCookie;
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = byteArray.Length;
Stream dataStream = request.GetRequestStream();
dataStream.Write(byteArray, 0, byteArray.Length);
dataStream.Close();
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
string responseFromServer = reader.ReadToEnd();
reader.Close();
dataStream.Close();
response.Close();
if (!responseFromServer.Contains("Wrong password"))
{
LoginCookie.Add(response.Cookies);
return true;
}
return false;
}
private string GetMaplePath()
{
string maplePath = (string)Registry.GetValue(#"HKEY_LOCAL_MACHINE\SOFTWARE\Wizet\MapleStory", "ExecPath", "");
return File.Exists(maplePath) ? maplePath : (string)Registry.GetValue(#"HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Wizet\MapleStory", "ExecPath", "");
}
public void Start()
{
ProcessStartInfo maplestory = new ProcessStartInfo();
maplestory.FileName = GetMaplePath() + #"\MapleStory.exe";
maplestory.Arguments = "WebStart " + LoginCookie.GetCookies(new Uri("http://nexon.net"))[0].ToString().Substring(4);
Process.Start(maplestory);
}
original code: http://pastie.org/private/vgpxht8tehtdjml2jdq

Your problem is that
LoginCookie.GetCookies(new Uri("http://nexon.net"))[0].ToString()
returns a string with less than 5 characters. So, doing
LoginCookie.GetCookies(new Uri("http://nexon.net"))[0].ToString().Substring(4)
will fail, since there will be no character at position 4. You have to check the string length before dealing with it.