Zyan example: two-factor authentication process

test.cs

// csc test.cs /r:Zyan.Communication.dll /debug

using System;
using System.Runtime.Serialization;
using System.Security;
using System.Text;
using System.Threading;
using Zyan.Communication;
using Zyan.Communication.Protocols.Tcp;
using Zyan.Communication.Security;
using Zyan.Communication.Security.Exceptions;

class Program
{
	static void Main(string[] args)
	{
		try
		{
			RunServer();
		}
		catch // port already taken
		{
			RunClient();
		}
	}

	static void RunClient()
	{
		// prepare credentials
		var credentials = new MyCredentials();
		Console.Write("User name: ");
		credentials.UserName = Console.ReadLine();
		Console.Write("Password: ");
		credentials.Password = Console.ReadLine();

		// establish connection
		var protocol = new TcpDuplexClientProtocolSetup(true);
		using (var conn = new ZyanConnection("tcpex://localhost:1234/RandomStringGenerator", protocol, credentials, true, true))
		{
			Console.WriteLine("\nConnected!\nPress Ctrl+C to exit.\n");

			var proxy = conn.CreateProxy<ISampleService>();
			while (true)
			{
				Console.WriteLine("Server sends: {0}", proxy.GetRandomString());
			}
		}
	}

	static void RunServer()
	{
		var auth = new MyAuthProvider();
		var protocol = new TcpDuplexServerProtocolSetup(1234, auth, true);
		using (var host = new ZyanComponentHost("RandomStringGenerator", protocol))
		{
			host.RegisterComponent<ISampleService, SampleService>();
			Console.WriteLine("Server started. Press Enter to exit.");
			Console.ReadLine();
		}
	}
}

public interface ISampleService
{
	string GetRandomString();
}

class MyCredentials : AuthCredentials
{
	public override void Authenticate(Guid sessionId, IZyanDispatcher dispatcher)
	{
		const int MAX_RETRIES = 3;

		for (var i = 0; i < MAX_RETRIES; i++)
		{
			// ask for 2fa code
			Console.Write("SMS code: ");
			CredentialsHashtable["Code"] = Console.ReadLine();

			// try to log on
			var response = dispatcher.Logon(sessionId, CredentialsHashtable);
			if (response.Completed && response.Success)
			{
				return;
			}
		}

		throw new Exception("Too bad, wrong code was specified");
	}
}

class MyAuthProvider : IAuthenticationProvider
{
	public AuthResponseMessage Authenticate(AuthRequestMessage authRequest)
	{
		var login = authRequest.Credentials[AuthRequestMessage.CREDENTIAL_USERNAME] as string;
		var password = authRequest.Credentials[AuthRequestMessage.CREDENTIAL_PASSWORD] as string;
		var code = authRequest.Credentials["Code"] as string;

		if (code == null)
		{
			return HandleStep1(login, password);
		}

		return HandleStep2(login, password, code);
	}

	private AuthResponseMessage HandleStep1(string login, string password)
	{
		if (login == "hacker" && password == "secret")
		{
			// TODO: generate 2fa code, save it, send SMS to a user, etc
			return new AuthResponseMessage
			{
				Success = true,
				Completed = false // second step is pending
			};
		}

		return new AuthResponseMessage
		{
			Success = false,
			Exception = new AccountNotFoundException()
		};
	}

	private AuthResponseMessage HandleStep2(string login, string password, string code)
	{
		if (login == "hacker" && password == "secret")
		{
			return new AuthResponseMessage
			{
				Success = true,
				Completed = code == "1234"
			};
		}

		return new AuthResponseMessage
		{
			Success = false,
			Exception = new AccountNotFoundException()
		};
	}
}

public class SampleService : ISampleService
{
	Random rnd = new Random();

	const string AvailableChars = "abcdefghijklmnopqrstuvwxyz0123456789";

	public string GetRandomString()
	{
		var count = 3 + rnd.Next(10);
		var sb = new StringBuilder();
		for (var i = 0; i < count; i++)
		{
			var c = AvailableChars[rnd.Next(AvailableChars.Length)];
			sb.Append(c);
		}

		Thread.Sleep(rnd.Next(1000));
		return sb.ToString();
	}
}