Implementing WS-SecureConversation in Microsoft IssueVision

using System;
using System.Configuration;
using System.Data;
using System.Net;
using System.Web.Services.Protocols;
using System.Windows.Forms;
using Microsoft.Web.Services2;
using Microsoft.Web.Services2.Security;
using Microsoft.Web.Services2.Security.Tokens;
using IssueVision.localhost;

namespace IssueVision
{
	public enum WebServicesExceptionType
	{
		WebExceptionFirstUse = 0,
		WebException = 1,
		SoapException = 2,
		Exception = 3,
		None = 4,
	}

	public class WebServicesLayer
	{
		public const string IV_WEBEXCEPTION_TEXT = "The server is not responding. Please try again.";
		public const string IV_WEBEXCEPTION_TITLE = "Network Error";
		public const string IV_WEBEXCEPTIONOFFLINEOK_TEXT = "The server is not responding. Starting IssueVision in offline mode.";
		public const string IV_WEBEXCEPTIONOFFLINEOK_TITLE = "Network Error - Working Offline";
		public const string IV_SOAPEXCEPTION_TEXT = "The system could not log you on.";
		public const string IV_SOAPEXCEPTION_TITLE = "Login Error";
		public const string IV_EXCEPTION_TEXT = "An unknown error has occurred";
		public const string IV_EXCEPTION_TITLE = "Unknown Error";

		public static void HandleWebServicesException(WebServicesExceptionType exceptionType)
		{
			switch (exceptionType)
			{
				case WebServicesExceptionType.WebException:
					MessageBox.Show(IV_WEBEXCEPTION_TEXT, IV_WEBEXCEPTION_TITLE, MessageBoxButtons.OK, MessageBoxIcon.Error);
					break;

				case WebServicesExceptionType.SoapException:
					MessageBox.Show(IV_SOAPEXCEPTION_TEXT, IV_SOAPEXCEPTION_TITLE, MessageBoxButtons.OK, MessageBoxIcon.Error);
					break;

				case WebServicesExceptionType.Exception:
					MessageBox.Show(IV_EXCEPTION_TEXT, IV_EXCEPTION_TITLE, MessageBoxButtons.OK, MessageBoxIcon.Error);
					break;
			}
		}

		public static WebServicesExceptionType Authenticate()
		{
			return Authenticate(UserSettings.Instance.Username, UserSettings.Instance.Password);
		}

		public static WebServicesExceptionType Authenticate(string username, string password)
		{
			WebServicesExceptionType exceptionType = WebServicesExceptionType.None;
			
			try
			{
				Wse2HelperClient.RequestSCTByUsername(username, password);
			}
			catch (WebException)
			{
				exceptionType = WebServicesExceptionType.WebException;
			}
			catch (SoapException soapEx)
			{
				if (soapEx.Actor == "Security")
				{
					exceptionType = WebServicesExceptionType.SoapException;
				}
				else
				{
					exceptionType = WebServicesExceptionType.WebException;
				}
			}
			catch (Exception)
			{
				exceptionType = WebServicesExceptionType.Exception;
			}
			
			return exceptionType;
		}

		// The GetLookupTables method is used to fetch lookup data such as Staffer information.  
		// The lookup data is refreshed each time the application is started while online.  
		// Unlike issue data, it is not updated in the background.
		public static IVDataSet GetLookupTables()
		{
			IVDataSet data = null;
			IssueVisionServicesWse dataService = GetWebServiceReference();
			
			try
			{
				// Request the security context token
				SecurityContextToken sct = Wse2HelperClient.RequestSCTByUsername(UserSettings.Instance.Username, UserSettings.Instance.Password);

				// Use the security context token to sign and encrypt a request to the Web service
				SoapContext requestContext = dataService.RequestSoapContext;
				requestContext.Security.Tokens.Add(sct);
				requestContext.Security.Elements.Add( new MessageSignature( sct ) );
				requestContext.Security.Elements.Add( new EncryptedData( sct ) );

				data = dataService.GetLookupTables();
			}
			catch (WebException)
			{
				HandleWebServicesException(WebServicesExceptionType.WebException);
			}
			catch (SoapException soapEx)
			{
				if (soapEx.Actor == "Security")
				{
					HandleWebServicesException(WebServicesExceptionType.SoapException);
				}
				else
				{
					HandleWebServicesException(WebServicesExceptionType.WebException);
				}
			}
			catch (Exception)
			{
				HandleWebServicesException(WebServicesExceptionType.Exception);
			}
						
			return data;
		}

		// SendReceiveIssues is a batch processing method that 1) sends data updates to 
		// the server, and 2) returns updated issue data since the last synchronization. 
		// When the application is set to Work Online, this method is called every few
		// seconds from the IssuesSubject and processed on a background thread.
		public static IVDataSet SendReceiveIssues(DataSet changedIssues, DateTime lastAccessed)
		{
			IVDataSet data = null;
			IssueVisionServicesWse dataService = GetWebServiceReference();
			
			try
			{
				// Request the security context token
				SecurityContextToken sct = Wse2HelperClient.RequestSCTByUsername(UserSettings.Instance.Username, UserSettings.Instance.Password);

				// Use the security context token to sign and encrypt a request to the Web service
				SoapContext requestContext = dataService.RequestSoapContext;
				requestContext.Security.Tokens.Add(sct);
				requestContext.Security.Elements.Add( new MessageSignature( sct ) );
				requestContext.Security.Elements.Add( new EncryptedData( sct ) );

				data = dataService.SendReceiveIssues(changedIssues, lastAccessed);
			}
			catch (WebException)
			{
				HandleWebServicesException(WebServicesExceptionType.WebException);
			}
			catch (SoapException soapEx)
			{
				if (soapEx.Actor == "Security")
				{
					HandleWebServicesException(WebServicesExceptionType.SoapException);
				}
				else
				{
					HandleWebServicesException(WebServicesExceptionType.WebException);
				}
			}
			catch (Exception)
			{
				HandleWebServicesException(WebServicesExceptionType.Exception);
			}
			
			return data;
		}

		// In IssueVision 1.0, this method returns an instance of the web reference for 
		// the IssueVisionService, with credentials attached as a custom SOAP header.
		// In version 1.1, the section marked below will be replaced with WSE 2.0 logic.
		private static IssueVisionServicesWse GetWebServiceReference()
		{
			IssueVisionServicesWse dataService = new IssueVisionServicesWse();
			
			string urlSetting = ConfigurationSettings.AppSettings["DataServiceUrl"];
			
			if (urlSetting != null)
			{
				dataService.Url = urlSetting;
			}
			else
			{
				dataService.Url = "http://localhost/IssueVisionWebWseCS/IssueVisionServices.asmx";
			}
			
			// wire up the default credentials in case the app is being run in a network
			// that requires authentication to a proxy server
			dataService.Credentials = (NetworkCredential)CredentialCache.DefaultCredentials;
			
			return dataService;
		}
	}
}