TokenRequestor.cs :  » Content-Management-Systems-CMS » N2 » Reimers » Google » C# / CSharp Open Source

using System;
using System.Net;
using System.Globalization;
using System.IO;
using System.Threading;

namespace Reimers.Google{
  public delegate void CallbackDelegate<T>(T item);

  public class TokenRequestor
  {
    #region Fields

    private static readonly string authUrlFormat = "accountType=GOOGLE&Email={0}&Passwd={1}&source=reimers.dk-analyticsreader-0.1&service=analytics";
    private static CultureInfo ci = CultureInfo.GetCultureInfo("en-US");
    private string _sidToken = string.Empty;
    private string _authToken = string.Empty;
    private string _lsidToken = string.Empty;
    private string _username = string.Empty;
    private string _password = string.Empty;
    private int _asyncWaitDelay = 1000;

    #endregion

    #region Constructor

    public TokenRequestor() { }

    public TokenRequestor(string username, string password)
      : this()
    {
      _username = username;
      _password = password;
    }

    #endregion

    #region Properties

    public string Username
    {
      get
      {
        return _username;
      }

      set
      {
        if (!string.Equals(_username, value))
        {
          _username = value;
          ClearTokens();
        }
      }
    }

    public string Password
    {
      get
      {
        return _password;
      }

      set
      {
        if (!string.Equals(_password, value))
        {
          _password = value;
          ClearTokens();
        }
      }
    }

    #endregion

    #region Methods

    private void ClearTokens()
    {
      if (Monitor.TryEnter(_sidToken, _asyncWaitDelay) && Monitor.TryEnter(_lsidToken, _asyncWaitDelay) && Monitor.TryEnter(_authToken, _asyncWaitDelay))
      {
        _sidToken = _lsidToken = _authToken = string.Empty;
        Monitor.Exit(_sidToken);
        Monitor.Exit(_lsidToken);
        Monitor.Exit(_authToken);
      }
    }

    private void GetTokens()
    {
      string u = string.Empty;
      string p = string.Empty;
      if (Monitor.TryEnter(_username, _asyncWaitDelay) && Monitor.TryEnter(_password, _asyncWaitDelay))
      {
        if (string.IsNullOrEmpty(_username) || string.IsNullOrEmpty(_password))
        {
          throw new ArgumentNullException("Username, Password", "Username and/or password not set");
        }
        u = _username;
        p = _password;
        Monitor.Exit(_username);
        Monitor.Exit(_password);
      }

      string authBody = string.Format(authUrlFormat, u, p);
      var req = (HttpWebRequest)WebRequest.Create("https://www.google.com/accounts/ClientLogin");
      req.Method = "POST";
      req.ContentType = "application/x-www-form-urlencoded";
      req.UserAgent = "Reimers.dk Token Requestor";
      Stream stream = req.GetRequestStream();
      var sw = new StreamWriter(stream);
      sw.Write(authBody);
      sw.Close();
      sw.Dispose();
      var response = (HttpWebResponse)req.GetResponse();
      var sr = new StreamReader(response.GetResponseStream());
      var token = sr.ReadToEnd();
      sr.Close();
      var tokens = token.Split(new[] { "\n" }, StringSplitOptions.RemoveEmptyEntries);
      foreach (string item in tokens)
      {
        if (item.StartsWith("Auth="))
        {
          _authToken = item.Replace("Auth=", string.Empty);
        }
        else if (item.StartsWith("SID="))
        {
          _sidToken = item.Replace("SID=", string.Empty);
        }
        else if (item.StartsWith("LSID="))
        {
          _lsidToken = item.Replace("LSID=", string.Empty);
        }
      }
    }

    public string GetSidToken()
    {
      if (string.IsNullOrEmpty(_sidToken))
      {
        GetTokens();
      }

      return _sidToken;
    }

    public void GetSidTokenAsync(CallbackDelegate<string> callback)
    {
      if (callback != null)
      {
        ThreadPool.QueueUserWorkItem(o =>
        {
          string sid = GetSidToken();
          callback(sid);
        });
      }
    }

    public string GetLsidToken()
    {
      if (string.IsNullOrEmpty(_lsidToken))
      {
        GetTokens();
      }

      return _lsidToken;
    }
    
    public void GetLsidTokenAsync(CallbackDelegate<string> callback)
    {
      if (callback != null)
      {
        ThreadPool.QueueUserWorkItem(o =>
        {
          string lsid = GetLsidToken();
          callback(lsid);
        });
      }
    }

    public string GetAuthToken()
    {
      if (string.IsNullOrEmpty(_authToken))
      {
        GetTokens();
      }
      
      return _authToken;
    }

    public void GetAuthTokenAsync(CallbackDelegate<string> callback)
    {
      if (callback != null)
      {
        ThreadPool.QueueUserWorkItem(o =>
        {
          string auth = GetAuthToken();
          callback(auth);
        });
      }
    }

    #endregion
  }
}