README.md

# NetCoreServer

[![Awesome .NET](https://awesome.re/badge.svg)](https://github.com/quozd/awesome-dotnet)
<br/>
[![Linux](https://github.com/chronoxor/NetCoreServer/actions/workflows/build-linux.yml/badge.svg)](https://github.com/chronoxor/NetCoreServer/actions/workflows/build-linux.yml)
[![MacOS](https://github.com/chronoxor/NetCoreServer/actions/workflows/build-macos.yml/badge.svg)](https://github.com/chronoxor/NetCoreServer/actions/workflows/build-macos.yml)
[![Windows (Visual Studio)](https://github.com/chronoxor/NetCoreServer/actions/workflows/build-windows.yml/badge.svg)](https://github.com/chronoxor/NetCoreServer/actions/workflows/build-windows.yml)
<br/>
[![NuGet](https://img.shields.io/nuget/v/NetCoreServer)](https://www.nuget.org/packages/NetCoreServer)

Ultra fast and low latency asynchronous socket server & client C# .NET Core
library with support TCP, SSL, UDP, Unix Domain Socket, HTTP, HTTPS, WebSocket protocols and [10K connections problem](https://en.wikipedia.org/wiki/C10k_problem)
solution.

Has integration with high-level message protocol based on [Fast Binary Encoding](https://github.com/chronoxor/FastBinaryEncoding)

[NetCoreServer documentation](https://chronoxor.github.io/NetCoreServer)<br/>
[NetCoreServer downloads](https://github.com/chronoxor/NetCoreServer/releases)<br/>

# Contents
  * [Features](#features)
  * [Requirements](#requirements)
  * [How to build?](#how-to-build)
  * [Examples](#examples)
    * [Example: TCP chat server](#example-tcp-chat-server)
    * [Example: TCP chat client](#example-tcp-chat-client)
    * [Example: SSL chat server](#example-ssl-chat-server)
    * [Example: SSL chat client](#example-ssl-chat-client)
    * [Example: UDP echo server](#example-udp-echo-server)
    * [Example: UDP echo client](#example-udp-echo-client)
    * [Example: UDP multicast server](#example-udp-multicast-server)
    * [Example: UDP multicast client](#example-udp-multicast-client)
    * [Example: Unix Domain Socket chat server](#example-unix-domain-socket-chat-server)
    * [Example: Unix Domain Socket chat client](#example-unix-domain-socket-chat-client)
    * [Example: Simple protocol](#example-simple-protocol)
    * [Example: Simple protocol server](#example-simple-protocol-server)
    * [Example: Simple protocol client](#example-simple-protocol-client)
    * [Example: HTTP server](#example-http-server)
    * [Example: HTTP client](#example-http-client)
    * [Example: HTTPS server](#example-https-server)
    * [Example: HTTPS client](#example-https-client)
    * [Example: WebSocket chat server](#example-websocket-chat-server)
    * [Example: WebSocket chat client](#example-websocket-chat-client)
    * [Example: WebSocket secure chat server](#example-websocket-secure-chat-server)
    * [Example: WebSocket secure chat client](#example-websocket-secure-chat-client)
  * [Performance](#performance)
    * [Benchmark: Round-Trip](#benchmark-round-trip)
      * [TCP echo server](#tcp-echo-server)
      * [SSL echo server](#ssl-echo-server)
      * [UDP echo server](#udp-echo-server)
      * [Unix Domain Socket echo server](#unix-domain-socket-echo-server)
      * [Simple protocol server](#simple-protocol-server)
      * [WebSocket echo server](#websocket-echo-server)
      * [WebSocket secure echo server](#websocket-secure-echo-server)
    * [Benchmark: Multicast](#benchmark-multicast)
      * [TCP multicast server](#tcp-multicast-server)
      * [SSL multicast server](#ssl-multicast-server)
      * [UDP multicast server](#udp-multicast-server)
      * [Unix Domain Socket multicast server](#unix-domain-socket-multicast-server)
      * [WebSocket multicast server](#websocket-multicast-server)
      * [WebSocket secure multicast server](#websocket-secure-multicast-server)
    * [Benchmark: Web Server](#benchmark-web-server)
      * [HTTP Trace server](#http-trace-server)
      * [HTTPS Trace server](#https-trace-server)
  * [OpenSSL certificates](#openssl-certificates)
    * [Production](#production)
    * [Development](#development)
    * [Certificate Authority](#certificate-authority)
    * [SSL Server certificate](#ssl-server-certificate)
    * [SSL Client certificate](#ssl-client-certificate)
    * [Diffie-Hellman key exchange](#diffie-hellman-key-exchange)

# Features
* Cross platform (Linux, MacOS, Windows)
* Asynchronous communication
* Supported transport protocols: [TCP](#example-tcp-chat-server), [SSL](#example-ssl-chat-server),
  [UDP](#example-udp-echo-server), [UDP multicast](#example-udp-multicast-server),
  [Unix Domain Socket](#example-unix-domain-socket-chat-server)
* Supported Web protocols: [HTTP](#example-http-server), [HTTPS](#example-https-server),
  [WebSocket](#example-websocket-chat-server), [WebSocket secure](#example-websocket-secure-chat-server)
* Supported [Swagger OpenAPI](https://swagger.io/specification/) iterative documentation
* Supported message protocol based on [Fast Binary Encoding](https://github.com/chronoxor/FastBinaryEncoding)

# Requirements
* Linux
* MacOS
* Windows
* [.NET 6.0](https://dotnet.microsoft.com/en-us/download/dotnet/6.0)
* [7-Zip](https://www.7-zip.org)
* [cmake](https://www.cmake.org)
* [git](https://git-scm.com)
* [Visual Studio](https://www.visualstudio.com)

Optional:
* [Rider](https://www.jetbrains.com/rider)

# How to build?

### Setup repository
```shell
git clone https://github.com/chronoxor/NetCoreServer.git
cd NetCoreServer
```

### Linux
```shell
cd build
./unix.sh
```

### MacOS
```shell
cd build
./unix.sh
```

### Windows (Visual Studio)
Open and build [NetCoreServer.sln](https://github.com/chronoxor/NetCoreServer/blob/master/NetCoreServer.sln) or run the build script:
```shell
cd build
vs.bat
```

The build script will create "release" directory with zip files:
* NetCoreServer.zip - C# Server assembly
* Benchmarks.zip - C# Server benchmarks
* Examples.zip - C# Server examples

# Examples

## Example: TCP chat server
Here comes the example of the TCP chat server. It handles multiple TCP client
sessions and multicast received message from any session to all ones. Also it
is possible to send admin message directly from the server.

```c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using NetCoreServer;

namespace TcpChatServer
{
    class ChatSession : TcpSession
    {
        public ChatSession(TcpServer server) : base(server) {}

        protected override void OnConnected()
        {
            Console.WriteLine($"Chat TCP session with Id {Id} connected!");

            // Send invite message
            string message = "Hello from TCP chat! Please send a message or '!' to disconnect the client!";
            SendAsync(message);
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Chat TCP session with Id {Id} disconnected!");
        }

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            string message = Encoding.UTF8.GetString(buffer, (int)offset, (int)size);
            Console.WriteLine("Incoming: " + message);

            // Multicast message to all connected sessions
            Server.Multicast(message);

            // If the buffer starts with '!' the disconnect the current session
            if (message == "!")
                Disconnect();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat TCP session caught an error with code {error}");
        }
    }

    class ChatServer : TcpServer
    {
        public ChatServer(IPAddress address, int port) : base(address, port) {}

        protected override TcpSession CreateSession() { return new ChatSession(this); }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat TCP server caught an error with code {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // TCP server port
            int port = 1111;
            if (args.Length > 0)
                port = int.Parse(args[0]);

            Console.WriteLine($"TCP server port: {port}");

            Console.WriteLine();

            // Create a new TCP chat server
            var server = new ChatServer(IPAddress.Any, port);

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Multicast admin message to all sessions
                line = "(admin) " + line;
                server.Multicast(line);
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: TCP chat client
Here comes the example of the TCP chat client. It connects to the TCP chat
server and allows to send message to it and receive new messages.

```c#
using System;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using TcpClient = NetCoreServer.TcpClient;

namespace TcpChatClient
{
    class ChatClient : TcpClient
    {
        public ChatClient(string address, int port) : base(address, port) {}

        public void DisconnectAndStop()
        {
            _stop = true;
            DisconnectAsync();
            while (IsConnected)
                Thread.Yield();
        }

        protected override void OnConnected()
        {
            Console.WriteLine($"Chat TCP client connected a new session with Id {Id}");
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Chat TCP client disconnected a session with Id {Id}");

            // Wait for a while...
            Thread.Sleep(1000);

            // Try to connect again
            if (!_stop)
                ConnectAsync();
        }

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            Console.WriteLine(Encoding.UTF8.GetString(buffer, (int)offset, (int)size));
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat TCP client caught an error with code {error}");
        }

        private bool _stop;
    }

    class Program
    {
        static void Main(string[] args)
        {
            // TCP server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // TCP server port
            int port = 1111;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"TCP server address: {address}");
            Console.WriteLine($"TCP server port: {port}");

            Console.WriteLine();

            // Create a new TCP chat client
            var client = new ChatClient(address, port);

            // Connect the client
            Console.Write("Client connecting...");
            client.ConnectAsync();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Disconnect the client
                if (line == "!")
                {
                    Console.Write("Client disconnecting...");
                    client.DisconnectAsync();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Send the entered text to the chat server
                client.SendAsync(line);
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: SSL chat server
Here comes the example of the SSL chat server. It handles multiple SSL client
sessions and multicast received message from any session to all ones. Also it
is possible to send admin message directly from the server.

This example is very similar to the TCP one except the code that prepares SSL
context and handshake handler.

```c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using NetCoreServer;

namespace SslChatServer
{
    class ChatSession : SslSession
    {
        public ChatSession(SslServer server) : base(server) {}

        protected override void OnConnected()
        {
            Console.WriteLine($"Chat SSL session with Id {Id} connected!");
        }

        protected override void OnHandshaked()
        {
            Console.WriteLine($"Chat SSL session with Id {Id} handshaked!");

            // Send invite message
            string message = "Hello from SSL chat! Please send a message or '!' to disconnect the client!";
            Send(message);
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Chat SSL session with Id {Id} disconnected!");
        }

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            string message = Encoding.UTF8.GetString(buffer, (int)offset, (int)size);
            Console.WriteLine("Incoming: " + message);

            // Multicast message to all connected sessions
            Server.Multicast(message);

            // If the buffer starts with '!' the disconnect the current session
            if (message == "!")
                Disconnect();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat SSL session caught an error with code {error}");
        }
    }

    class ChatServer : SslServer
    {
        public ChatServer(SslContext context, IPAddress address, int port) : base(context, address, port) {}

        protected override SslSession CreateSession() { return new ChatSession(this); }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat SSL server caught an error with code {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // SSL server port
            int port = 2222;
            if (args.Length > 0)
                port = int.Parse(args[0]);

            Console.WriteLine($"SSL server port: {port}");

            Console.WriteLine();

            // Create and prepare a new SSL server context
            var context = new SslContext(SslProtocols.Tls12, new X509Certificate2("server.pfx", "qwerty"));

            // Create a new SSL chat server
            var server = new ChatServer(context, IPAddress.Any, port);

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Multicast admin message to all sessions
                line = "(admin) " + line;
                server.Multicast(line);
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: SSL chat client
Here comes the example of the SSL chat client. It connects to the SSL chat
server and allows to send message to it and receive new messages.

This example is very similar to the TCP one except the code that prepares SSL
context and handshake handler.

```c#
using System;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading;
using NetCoreServer;

namespace SslChatClient
{
    class ChatClient : SslClient
    {
        public ChatClient(SslContext context, string address, int port) : base(context, address, port) {}

        public void DisconnectAndStop()
        {
            _stop = true;
            DisconnectAsync();
            while (IsConnected)
                Thread.Yield();
        }

        protected override void OnConnected()
        {
            Console.WriteLine($"Chat SSL client connected a new session with Id {Id}");
        }

        protected override void OnHandshaked()
        {
            Console.WriteLine($"Chat SSL client handshaked a new session with Id {Id}");
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Chat SSL client disconnected a session with Id {Id}");

            // Wait for a while...
            Thread.Sleep(1000);

            // Try to connect again
            if (!_stop)
                ConnectAsync();
        }

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            Console.WriteLine(Encoding.UTF8.GetString(buffer, (int)offset, (int)size));
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat SSL client caught an error with code {error}");
        }

        private bool _stop;
    }

    class Program
    {
        static void Main(string[] args)
        {
            // SSL server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // SSL server port
            int port = 2222;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"SSL server address: {address}");
            Console.WriteLine($"SSL server port: {port}");

            Console.WriteLine();

            // Create and prepare a new SSL client context
            var context = new SslContext(SslProtocols.Tls12, new X509Certificate2("client.pfx", "qwerty"), (sender, certificate, chain, sslPolicyErrors) => true);

            // Create a new SSL chat client
            var client = new ChatClient(context, address, port);

            // Connect the client
            Console.Write("Client connecting...");
            client.ConnectAsync();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Disconnect the client
                if (line == "!")
                {
                    Console.Write("Client disconnecting...");
                    client.DisconnectAsync();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Send the entered text to the chat server
                client.SendAsync(line);
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: UDP echo server
Here comes the example of the UDP echo server. It receives a datagram mesage
from any UDP client and resend it back without any changes.

```c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using NetCoreServer;

namespace UdpEchoServer
{
    class EchoServer : UdpServer
    {
        public EchoServer(IPAddress address, int port) : base(address, port) {}

        protected override void OnStarted()
        {
            // Start receive datagrams
            ReceiveAsync();
        }

        protected override void OnReceived(EndPoint endpoint, byte[] buffer, long offset, long size)
        {
            Console.WriteLine("Incoming: " + Encoding.UTF8.GetString(buffer, (int)offset, (int)size));

            // Echo the message back to the sender
            SendAsync(endpoint, buffer, 0, size);
        }

        protected override void OnSent(EndPoint endpoint, long sent)
        {
            // Continue receive datagrams
            ReceiveAsync();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Echo UDP server caught an error with code {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // UDP server port
            int port = 3333;
            if (args.Length > 0)
                port = int.Parse(args[0]);

            Console.WriteLine($"UDP server port: {port}");

            Console.WriteLine();

            // Create a new UDP echo server
            var server = new EchoServer(IPAddress.Any, port);

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                }
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: UDP echo client
Here comes the example of the UDP echo client. It sends user datagram message
to UDP server and listen for response.

```c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using UdpClient = NetCoreServer.UdpClient;

namespace UdpEchoClient
{
    class EchoClient : UdpClient
    {
        public EchoClient(string address, int port) : base(address, port) {}

        public void DisconnectAndStop()
        {
            _stop = true;
            Disconnect();
            while (IsConnected)
                Thread.Yield();
        }

        protected override void OnConnected()
        {
            Console.WriteLine($"Echo UDP client connected a new session with Id {Id}");

            // Start receive datagrams
            ReceiveAsync();
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Echo UDP client disconnected a session with Id {Id}");

            // Wait for a while...
            Thread.Sleep(1000);

            // Try to connect again
            if (!_stop)
                Connect();
        }

        protected override void OnReceived(EndPoint endpoint, byte[] buffer, long offset, long size)
        {
            Console.WriteLine("Incoming: " + Encoding.UTF8.GetString(buffer, (int)offset, (int)size));

            // Continue receive datagrams
            ReceiveAsync();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Echo UDP client caught an error with code {error}");
        }

        private bool _stop;
    }

    class Program
    {
        static void Main(string[] args)
        {
            // UDP server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // UDP server port
            int port = 3333;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"UDP server address: {address}");
            Console.WriteLine($"UDP server port: {port}");

            Console.WriteLine();

            // Create a new TCP chat client
            var client = new EchoClient(address, port);

            // Connect the client
            Console.Write("Client connecting...");
            client.Connect();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Disconnect the client
                if (line == "!")
                {
                    Console.Write("Client disconnecting...");
                    client.Disconnect();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Send the entered text to the chat server
                client.Send(line);
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: UDP multicast server
Here comes the example of the UDP multicast server. It use multicast IP address
to multicast datagram messages to all client that joined corresponding UDP
multicast group.

```c#
using System;
using System.Net;
using System.Net.Sockets;
using NetCoreServer;

namespace UdpMulticastServer
{
    class MulticastServer : UdpServer
    {
        public MulticastServer(IPAddress address, int port) : base(address, port) {}

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Multicast UDP server caught an error with code {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // UDP multicast address
            string multicastAddress = "239.255.0.1";
            if (args.Length > 0)
                multicastAddress = args[0];

            // UDP multicast port
            int multicastPort = 3334;
            if (args.Length > 1)
                multicastPort = int.Parse(args[1]);

            Console.WriteLine($"UDP multicast address: {multicastAddress}");
            Console.WriteLine($"UDP multicast port: {multicastPort}");

            Console.WriteLine();

            // Create a new UDP multicast server
            var server = new MulticastServer(IPAddress.Any, 0);

            // Start the multicast server
            Console.Write("Server starting...");
            server.Start(multicastAddress, multicastPort);
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Multicast admin message to all sessions
                line = "(admin) " + line;
                server.Multicast(line);
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: UDP multicast client
Here comes the example of the UDP multicast client. It use multicast IP address
and joins UDP multicast group in order to receive multicasted datagram messages
from UDP server.

```c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using UdpClient = NetCoreServer.UdpClient;

namespace UdpMulticastClient
{
    class MulticastClient : UdpClient
    {
        public string Multicast;

        public MulticastClient(string address, int port) : base(address, port) {}

        public void DisconnectAndStop()
        {
            _stop = true;
            Disconnect();
            while (IsConnected)
                Thread.Yield();
        }

        protected override void OnConnected()
        {
            Console.WriteLine($"Multicast UDP client connected a new session with Id {Id}");

            // Join UDP multicast group
            JoinMulticastGroup(Multicast);

            // Start receive datagrams
            ReceiveAsync();
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Multicast UDP client disconnected a session with Id {Id}");

            // Wait for a while...
            Thread.Sleep(1000);

            // Try to connect again
            if (!_stop)
                Connect();
        }

        protected override void OnReceived(EndPoint endpoint, byte[] buffer, long offset, long size)
        {
            Console.WriteLine("Incoming: " + Encoding.UTF8.GetString(buffer, (int)offset, (int)size));

            // Continue receive datagrams
            ReceiveAsync();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Multicast UDP client caught an error with code {error}");
        }

        private bool _stop;
    }

    class Program
    {
        static void Main(string[] args)
        {
            // UDP listen address
            string listenAddress = "0.0.0.0";
            if (args.Length > 0)
                listenAddress = args[0];

            // UDP multicast address
            string multicastAddress = "239.255.0.1";
            if (args.Length > 1)
                multicastAddress = args[1];

            // UDP multicast port
            int multicastPort = 3334;
            if (args.Length > 2)
                multicastPort = int.Parse(args[2]);

            Console.WriteLine($"UDP listen address: {listenAddress}");
            Console.WriteLine($"UDP multicast address: {multicastAddress}");
            Console.WriteLine($"UDP multicast port: {multicastPort}");

            Console.WriteLine();

            // Create a new TCP chat client
            var client = new MulticastClient(listenAddress, multicastPort);
            client.SetupMulticast(true);
            client.Multicast = multicastAddress;

            // Connect the client
            Console.Write("Client connecting...");
            client.Connect();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Disconnect the client
                if (line == "!")
                {
                    Console.Write("Client disconnecting...");
                    client.Disconnect();
                    Console.WriteLine("Done!");
                    continue;
                }
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: Unix Domain Socket chat server
Here comes the example of the  Unix  Domain  Socket  chat  server.  It  handles
multiple Unix Domain Socket client sessions and multicast received message from
any session to all ones. Also it is possible to  send  admin  message  directly
from the server.

```c#
using System;
using System.IO;
using System.Net.Sockets;
using System.Text;
using NetCoreServer;

namespace UdsChatServer
{
    class ChatSession : UdsSession
    {
        public ChatSession(UdsServer server) : base(server) {}

        protected override void OnConnected()
        {
            Console.WriteLine($"Chat Unix Domain Socket session with Id {Id} connected!");

            // Send invite message
            string message = "Hello from Unix Domain Socket chat! Please send a message or '!' to disconnect the client!";
            SendAsync(message);
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Chat Unix Domain Socket session with Id {Id} disconnected!");
        }

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            string message = Encoding.UTF8.GetString(buffer, (int)offset, (int)size);
            Console.WriteLine("Incoming: " + message);

            // Multicast message to all connected sessions
            Server.Multicast(message);

            // If the buffer starts with '!' the disconnect the current session
            if (message == "!")
                Disconnect();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat Unix Domain Socket session caught an error with code {error}");
        }
    }

    class ChatServer : UdsServer
    {
        public ChatServer(string path) : base(path) {}

        protected override UdsSession CreateSession() { return new ChatSession(this); }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat Unix Domain Socket server caught an error with code {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // Unix Domain Socket path
            string path = Path.Combine(Path.GetTempPath(), "chat.sock");
            if (args.Length > 0)
                path = args[0];

            Console.WriteLine($"Unix Domain Socket server path: {path}");

            Console.WriteLine();

            // Create a new Unix Domain Socket chat server
            var server = new ChatServer(path);

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Multicast admin message to all sessions
                line = "(admin) " + line;
                server.Multicast(line);
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: Unix Domain Socket chat client
Here comes the example of the Unix Domain Socket chat client.  It  connects  to
the Unix Domain Socket chat server and allows to send message to it and receive
new messages.

```c#
using System;
using System.IO;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using UdsClient = NetCoreServer.UdsClient;

namespace UdsChatClient
{
    class ChatClient : UdsClient
    {
        public ChatClient(string path) : base(path) {}

        public void DisconnectAndStop()
        {
            _stop = true;
            DisconnectAsync();
            while (IsConnected)
                Thread.Yield();
        }

        protected override void OnConnected()
        {
            Console.WriteLine($"Chat Unix Domain Socket client connected a new session with Id {Id}");
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"Chat Unix Domain Socket client disconnected a session with Id {Id}");

            // Wait for a while...
            Thread.Sleep(1000);

            // Try to connect again
            if (!_stop)
                ConnectAsync();
        }

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            Console.WriteLine(Encoding.UTF8.GetString(buffer, (int)offset, (int)size));
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat Unix Domain Socket client caught an error with code {error}");
        }

        private bool _stop;
    }

    class Program
    {
        static void Main(string[] args)
        {
            // Unix Domain Socket path
            string path = Path.Combine(Path.GetTempPath(), "chat.sock");
            if (args.Length > 0)
                path = args[0];

            Console.WriteLine($"Unix Domain Socket server path: {path}");

            Console.WriteLine();

            // Create a new Unix Domain Socket chat client
            var client = new ChatClient(path);

            // Connect the client
            Console.Write("Client connecting...");
            client.ConnectAsync();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Disconnect the client
                if (line == "!")
                {
                    Console.Write("Client disconnecting...");
                    client.DisconnectAsync();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Send the entered text to the chat server
                client.SendAsync(line);
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: Simple protocol
Simple protocol is defined in [simple.fbe](https://github.com/chronoxor/NetCoreServer/blob/master/proto/simple.fbe) file:

```proto
/*
   Simple Fast Binary Encoding protocol for CppServer
   https://github.com/chronoxor/FastBinaryEncoding

   Generate protocol command: fbec --csharp --proto --input=simple.fbe --output=.
*/

// Domain declaration
domain com.chronoxor

// Package declaration
package simple

// Protocol version
version 1.0

// Simple request message
[request]
[response(SimpleResponse)]
[reject(SimpleReject)]
message SimpleRequest
{
    // Request Id
    uuid [id] = uuid1;
    // Request message
    string Message;
}

// Simple response
message SimpleResponse
{
    // Response Id
    uuid [id] = uuid1;
    // Calculated message length
    uint32 Length;
    // Calculated message hash
    uint32 Hash;
}

// Simple reject
message SimpleReject
{
    // Reject Id
    uuid [id] = uuid1;
    // Error message
    string Error;
}

// Simple notification
message SimpleNotify
{
    // Server notification
    string Notification;
}

// Disconnect request message
[request]
message DisconnectRequest
{
    // Request Id
    uuid [id] = uuid1;
}
```

## Example: Simple protocol server
Here comes the example of  the  simple  protocol  server.  It  process  client
requests, answer with corresponding responses and  send  server  notifications
back to clients.

```c#
using System;
using System.Net;
using System.Net.Sockets;
using NetCoreServer;

using com.chronoxor.simple;
using com.chronoxor.simple.FBE;

namespace ProtoServer
{
    public class SimpleProtoSessionSender : Sender, ISenderListener
    {
        public SimpleProtoSession Session { get; }

        public SimpleProtoSessionSender(SimpleProtoSession session) { Session = session; }

        public long OnSend(byte[] buffer, long offset, long size)
        {
            return Session.SendAsync(buffer, offset, size) ? size : 0;
        }
    }

    public class SimpleProtoSessionReceiver : Receiver, IReceiverListener
    {
        public SimpleProtoSession Session { get; }

        public SimpleProtoSessionReceiver(SimpleProtoSession session) { Session = session; }

        public void OnReceive(DisconnectRequest request) { Session.OnReceive(request); }
        public void OnReceive(SimpleRequest request) { Session.OnReceive(request); }
    }

    public class SimpleProtoSession : TcpSession
    {
        public SimpleProtoSessionSender Sender { get; }
        public SimpleProtoSessionReceiver Receiver { get; }

        public SimpleProtoSession(TcpServer server) : base(server)
        {
            Sender = new SimpleProtoSessionSender(this);
            Receiver = new SimpleProtoSessionReceiver(this);
        }

        protected override void OnConnected()
        {
            Console.WriteLine($"TCP protocol session with Id '{Id}' connected to remote address '{(Socket.RemoteEndPoint as IPEndPoint)?.Address}' and port {(Socket.RemoteEndPoint as IPEndPoint)?.Port}");

            // Send invite notification
            SimpleNotify notify = SimpleNotify.Default;
            notify.Notification = "Hello from Simple protocol server! Please send a message or '!' to disconnect the client!";
            Sender.Send(notify);
        }

        protected override void OnDisconnected()
        {
            Console.WriteLine($"TCP protocol session with Id '{Id}' disconnected");
        }

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            Receiver.Receive(buffer, offset, size);
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"TCP protocol session with Id '{Id}' caught a socket error: {error}");
        }

        // Protocol handlers
        public void OnReceive(DisconnectRequest request) { Disconnect(); }
        public void OnReceive(SimpleRequest request)
        {
            Console.WriteLine($"Received: {request}");

            // Validate request
            if (string.IsNullOrEmpty(request.Message))
            {
                // Send reject
                SimpleReject reject = SimpleReject.Default;
                reject.id = request.id;
                reject.Error = "Request message is empty!";
                Sender.Send(reject);
                return;
            }

            // Send response
            SimpleResponse response = SimpleResponse.Default;
            response.id = request.id;
            response.Hash = (uint)request.Message.GetHashCode();
            response.Length = (uint)request.Message.Length;
            Sender.Send(response);
        }
    }

    public class SimpleProtoSender : Sender, ISenderListener
    {
        public SimpleProtoServer Server { get; }

        public SimpleProtoSender(SimpleProtoServer server) { Server = server; }

        public long OnSend(byte[] buffer, long offset, long size)
        {
            Server.Multicast(buffer, offset, size);
            return size;
        }
    }

    public class SimpleProtoServer : TcpServer
    {
        public SimpleProtoSender Sender { get; }

        public SimpleProtoServer(IPAddress address, int port) : base(address, port)
        {
            Sender = new SimpleProtoSender(this);
        }

        protected override TcpSession CreateSession() { return new SimpleProtoSession(this); }

        protected override void OnStarted()
        {
            Console.WriteLine($"Simple protocol server with Id '{Id}' started!");
        }

        protected override void OnStopped()
        {
            Console.WriteLine($"Simple protocol server with Id '{Id}' stopped!");
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Simple protocol server with Id '{Id}' caught an error: {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // Simple protocol server port
            int port = 4444;
            if (args.Length > 0)
                port = int.Parse(args[0]);

            Console.WriteLine($"Simple protocol server port: {port}");

            Console.WriteLine();

            // Create a new simple protocol server
            var server = new SimpleProtoServer(IPAddress.Any, port);

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Multicast admin notification to all sessions
                SimpleNotify notify = SimpleNotify.Default;
                notify.Notification = "(admin) " + line;
                server.Sender.Send(notify);
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: Simple protocol client
Here comes the example of the simple  protocol  client.  It  connects  to  the
simple protocol  server  and  allows  to  send  requests  to  it  and  receive
corresponding responses.

```c#
using System;
using System.Net.Sockets;
using System.Threading;
using TcpClient = NetCoreServer.TcpClient;

using com.chronoxor.simple;
using com.chronoxor.simple.FBE;

namespace ProtoClient
{
    public class TcpProtoClient : TcpClient
    {
        public TcpProtoClient(string address, int port) : base(address, port) {}

        public bool ConnectAndStart()
        {
            Console.WriteLine($"TCP protocol client starting a new session with Id '{Id}'...");

            StartReconnectTimer();
            return ConnectAsync();
        }

        public bool DisconnectAndStop()
        {
            Console.WriteLine($"TCP protocol client stopping the session with Id '{Id}'...");

            StopReconnectTimer();
            DisconnectAsync();
            return true;
        }

        public override bool Reconnect()
        {
            return ReconnectAsync();
        }

        private Timer _reconnectTimer;

        public void StartReconnectTimer()
        {
            // Start the reconnect timer
            _reconnectTimer = new Timer(state =>
            {
                Console.WriteLine($"TCP reconnect timer connecting the client session with Id '{Id}'...");
                ConnectAsync();
            }, null, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan);
        }

        public void StopReconnectTimer()
        {
            // Stop the reconnect timer
            _reconnectTimer?.Dispose();
            _reconnectTimer = null;
        }

        public delegate void ConnectedHandler();
        public event ConnectedHandler Connected = () => {};

        protected override void OnConnected()
        {
            Console.WriteLine($"TCP protocol client connected a new session with Id '{Id}' to remote address '{Address}' and port {Port}");

            Connected?.Invoke();
        }

        public delegate void DisconnectedHandler();
        public event DisconnectedHandler Disconnected = () => {};

        protected override void OnDisconnected()
        {
            Console.WriteLine($"TCP protocol client disconnected the session with Id '{Id}'");

            // Setup and asynchronously wait for the reconnect timer
            _reconnectTimer?.Change(TimeSpan.FromSeconds(1), Timeout.InfiniteTimeSpan);

            Disconnected?.Invoke();
        }

        public delegate void ReceivedHandler(byte[] buffer, long offset, long size);
        public event ReceivedHandler Received = (buffer, offset, size) => {};

        protected override void OnReceived(byte[] buffer, long offset, long size)
        {
            Received?.Invoke(buffer, offset, size);
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"TCP protocol client caught a socket error: {error}");
        }

        #region IDisposable implementation

        // Disposed flag.
        private bool _disposed;

        protected override void Dispose(bool disposingManagedResources)
        {
            if (!_disposed)
            {
                if (disposingManagedResources)
                {
                    // Dispose managed resources here...
                    StopReconnectTimer();
                }

                // Dispose unmanaged resources here...

                // Set large fields to null here...

                // Mark as disposed.
                _disposed = true;
            }

            // Call Dispose in the base class.
            base.Dispose(disposingManagedResources);
        }

        // The derived class does not have a Finalize method
        // or a Dispose method without parameters because it inherits
        // them from the base class.

        #endregion
    }

    public class SimpleProtoClient : Client, ISenderListener, IReceiverListener, IDisposable
    {
        private readonly TcpProtoClient _tcpProtoClient;

        public Guid Id => _tcpProtoClient.Id;
        public bool IsConnected => _tcpProtoClient.IsConnected;

        public SimpleProtoClient(string address, int port)
        {
            _tcpProtoClient = new TcpProtoClient(address, port);
            _tcpProtoClient.Connected += OnConnected;
            _tcpProtoClient.Disconnected += OnDisconnected;
            _tcpProtoClient.Received += OnReceived;
            ReceivedResponse_DisconnectRequest += HandleDisconnectRequest;
            ReceivedResponse_SimpleResponse += HandleSimpleResponse;
            ReceivedResponse_SimpleReject += HandleSimpleReject;
            ReceivedResponse_SimpleNotify += HandleSimpleNotify;
        }

        private void DisposeClient()
        {
            _tcpProtoClient.Connected -= OnConnected;
            _tcpProtoClient.Connected -= OnDisconnected;
            _tcpProtoClient.Received -= OnReceived;
            ReceivedResponse_DisconnectRequest -= HandleDisconnectRequest;
            ReceivedResponse_SimpleResponse -= HandleSimpleResponse;
            ReceivedResponse_SimpleReject -= HandleSimpleReject;
            ReceivedResponse_SimpleNotify -= HandleSimpleNotify;
            _tcpProtoClient.Dispose();
        }

        public bool ConnectAndStart() { return _tcpProtoClient.ConnectAndStart(); }
        public bool DisconnectAndStop() { return _tcpProtoClient.DisconnectAndStop(); }
        public bool Reconnect() { return _tcpProtoClient.Reconnect(); }

        private bool _watchdog;
        private Thread _watchdogThread;

        public bool StartWatchdog()
        {
            if (_watchdog)
                return false;

            Console.WriteLine("Watchdog thread starting...");

            // Start the watchdog thread
            _watchdog = true;
            _watchdogThread = new Thread(WatchdogThread);

            Console.WriteLine("Watchdog thread started!");

            return true;
        }

        public bool StopWatchdog()
        {
            if (!_watchdog)
                return false;

            Console.WriteLine("Watchdog thread stopping...");

            // Stop the watchdog thread
            _watchdog = false;
            _watchdogThread.Join();

            Console.WriteLine("Watchdog thread stopped!");

            return true;
        }

        public static void WatchdogThread(object obj)
        {
            var instance = obj as SimpleProtoClient;
            if (instance == null)
                return;

            try
            {
                // Watchdog loop...
                while (instance._watchdog)
                {
                    var utc = DateTime.UtcNow;

                    // Watchdog the client
                    instance.Watchdog(utc);

                    // Sleep for a while...
                    Thread.Sleep(1000);
                }
            }
            catch (Exception e)
            {
                Console.WriteLine($"Config client watchdog thread terminated: {e}");
            }
        }

        #region Connection handlers

        public delegate void ConnectedHandler();
        public event ConnectedHandler Connected = () => {};

        private void OnConnected()
        {
            // Reset FBE protocol buffers
            Reset();

            Connected?.Invoke();
        }

        public delegate void DisconnectedHandler();
        public event DisconnectedHandler Disconnected = () => {};

        private void OnDisconnected()
        {
            Disconnected?.Invoke();
        }

        public long OnSend(byte[] buffer, long offset, long size)
        {
            return _tcpProtoClient.SendAsync(buffer, offset, size) ? size : 0;
        }

        public void OnReceived(byte[] buffer, long offset, long size)
        {
            Receive(buffer, offset, size);
        }

        #endregion

        #region Protocol handlers

        private void HandleDisconnectRequest(DisconnectRequest request) { Console.WriteLine($"Received: {request}"); _tcpProtoClient.DisconnectAsync(); }
        private void HandleSimpleResponse(SimpleResponse response) { Console.WriteLine($"Received: {response}"); }
        private void HandleSimpleReject(SimpleReject reject) { Console.WriteLine($"Received: {reject}"); }
        private void HandleSimpleNotify(SimpleNotify notify) { Console.WriteLine($"Received: {notify}"); }

        #endregion

        #region IDisposable implementation

        // Disposed flag.
        private bool _disposed;

        // Implement IDisposable.
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposingManagedResources)
        {
            // The idea here is that Dispose(Boolean) knows whether it is
            // being called to do explicit cleanup (the Boolean is true)
            // versus being called due to a garbage collection (the Boolean
            // is false). This distinction is useful because, when being
            // disposed explicitly, the Dispose(Boolean) method can safely
            // execute code using reference type fields that refer to other
            // objects knowing for sure that these other objects have not been
            // finalized or disposed of yet. When the Boolean is false,
            // the Dispose(Boolean) method should not execute code that
            // refer to reference type fields because those objects may
            // have already been finalized."

            if (!_disposed)
            {
                if (disposingManagedResources)
                {
                    // Dispose managed resources here...
                    DisposeClient();
                }

                // Dispose unmanaged resources here...

                // Set large fields to null here...

                // Mark as disposed.
                _disposed = true;
            }
        }

        #endregion
    }

    class Program
    {
        static void Main(string[] args)
        {
            // Simple protocol server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // Simple protocol server port
            int port = 4444;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"Simple protocol server address: {address}");
            Console.WriteLine($"Simple protocol server port: {port}");

            Console.WriteLine();

            // Create a new simple protocol chat client
            var client = new SimpleProtoClient(address, port);

            // Connect the client
            Console.Write("Client connecting...");
            client.ConnectAndStart();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Disconnect the client
                if (line == "!")
                {
                    Console.Write("Client disconnecting...");
                    client.Reconnect();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Send request to the simple protocol server
                SimpleRequest request = SimpleRequest.Default;
                request.Message = line;
                var response = client.Request(request).Result;

                // Show string hash calculation result
                Console.WriteLine($"Hash of '{line}' = 0x{response.Hash:X8}");
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: HTTP server
Here comes the example of the HTTP cache server. It allows to manipulate
cache data with HTTP methods (GET, POST, PUT and DELETE).

Use the following link to open [Swagger OpenAPI](https://swagger.io/specification/) iterative documentation: http://localhost:8080/api/index.html

![OpenAPI-HTTP](https://github.com/chronoxor/NetCoreServer/raw/master/images/openapi-http.png)

```c#
using System;
using System.Collections.Concurrent;
using System.Net;
using System.Net.Sockets;
using System.Text;
using NetCoreServer;

namespace HttpServer
{
    class CommonCache
    {
        public static CommonCache GetInstance()
        {
            if (_instance == null)
                _instance = new CommonCache();
            return _instance;
        }

        public string GetAllCache()
        {
            var result = new StringBuilder();
            result.Append("[\n");
            foreach (var item in _cache)
            {
                result.Append("  {\n");
                result.AppendFormat($"    \"key\": \"{item.Key}\",\n");
                result.AppendFormat($"    \"value\": \"{item.Value}\",\n");
                result.Append("  },\n");
            }
            result.Append("]\n");
            return result.ToString();
        }

        public bool GetCacheValue(string key, out string value)
        {
            return _cache.TryGetValue(key, out value);
        }

        public void PutCacheValue(string key, string value)
        {
            _cache[key] = value;
        }

        public bool DeleteCacheValue(string key, out string value)
        {
            return _cache.TryRemove(key, out value);
        }

        private readonly ConcurrentDictionary<string, string> _cache = new ConcurrentDictionary<string, string>();
        private static CommonCache _instance;
    }

    class HttpCacheSession : HttpSession
    {
        public HttpCacheSession(NetCoreServer.HttpServer server) : base(server) {}

        protected override void OnReceivedRequest(HttpRequest request)
        {
            // Show HTTP request content
            Console.WriteLine(request);

            // Process HTTP request methods
            if (request.Method == "HEAD")
                SendResponseAsync(Response.MakeHeadResponse());
            else if (request.Method == "GET")
            {
                string key = request.Url;

                // Decode the key value
                key = Uri.UnescapeDataString(key);
                key = key.Replace("/api/cache", "", StringComparison.InvariantCultureIgnoreCase);
                key = key.Replace("?key=", "", StringComparison.InvariantCultureIgnoreCase);

                if (string.IsNullOrEmpty(key))
                {
                    // Response with all cache values
                    SendResponseAsync(Response.MakeGetResponse(CommonCache.GetInstance().GetAllCache(), "application/json; charset=UTF-8"));
                }
                // Get the cache value by the given key
                else if (CommonCache.GetInstance().GetCacheValue(key, out var value))
                {
                    // Response with the cache value
                    SendResponseAsync(Response.MakeGetResponse(value));
                }
                else
                    SendResponseAsync(Response.MakeErrorResponse(404, "Required cache value was not found for the key: " + key));
            }
            else if ((request.Method == "POST") || (request.Method == "PUT"))
            {
                string key = request.Url;
                string value = request.Body;

                // Decode the key value
                key = Uri.UnescapeDataString(key);
                key = key.Replace("/api/cache", "", StringComparison.InvariantCultureIgnoreCase);
                key = key.Replace("?key=", "", StringComparison.InvariantCultureIgnoreCase);

                // Put the cache value
                CommonCache.GetInstance().PutCacheValue(key, value);

                // Response with the cache value
                SendResponseAsync(Response.MakeOkResponse());
            }
            else if (request.Method == "DELETE")
            {
                string key = request.Url;

                // Decode the key value
                key = Uri.UnescapeDataString(key);
                key = key.Replace("/api/cache", "", StringComparison.InvariantCultureIgnoreCase);
                key = key.Replace("?key=", "", StringComparison.InvariantCultureIgnoreCase);

                // Delete the cache value
                if (CommonCache.GetInstance().DeleteCacheValue(key, out var value))
                {
                    // Response with the cache value
                    SendResponseAsync(Response.MakeGetResponse(value));
                }
                else
                    SendResponseAsync(Response.MakeErrorResponse(404, "Deleted cache value was not found for the key: " + key));
            }
            else if (request.Method == "OPTIONS")
                SendResponseAsync(Response.MakeOptionsResponse());
            else if (request.Method == "TRACE")
                SendResponseAsync(Response.MakeTraceResponse(request.Cache.Data));
            else
                SendResponseAsync(Response.MakeErrorResponse("Unsupported HTTP method: " + request.Method));
        }

        protected override void OnReceivedRequestError(HttpRequest request, string error)
        {
            Console.WriteLine($"Request error: {error}");
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"HTTP session caught an error: {error}");
        }
    }

    class HttpCacheServer : NetCoreServer.HttpServer
    {
        public HttpCacheServer(IPAddress address, int port) : base(address, port) {}

        protected override TcpSession CreateSession() { return new HttpCacheSession(this); }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"HTTP session caught an error: {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // HTTP server port
            int port = 8080;
            if (args.Length > 0)
                port = int.Parse(args[0]);
            // HTTP server content path
            string www = "../../../../../www/api";
            if (args.Length > 1)
                www = args[1];

            Console.WriteLine($"HTTP server port: {port}");
            Console.WriteLine($"HTTP server static content path: {www}");
            Console.WriteLine($"HTTP server website: http://localhost:{port}/api/index.html");

            Console.WriteLine();

            // Create a new HTTP server
            var server = new HttpCacheServer(IPAddress.Any, port);
            server.AddStaticContent(www, "/api");

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                }
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: HTTP client
Here comes the example of the HTTP client. It allows to send HTTP requests
(GET, POST, PUT and DELETE) and receive HTTP responses.

```c#
using System;
using NetCoreServer;

namespace HttpClient
{
    class Program
    {
        static void Main(string[] args)
        {
            // HTTP server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // HTTP server port
            int port = 8080;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"HTTP server address: {address}");
            Console.WriteLine($"HTTP server port: {port}");

            Console.WriteLine();

            // Create a new HTTP client
            var client = new HttpClientEx(address, port);

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Reconnect the client
                if (line == "!")
                {
                    Console.Write("Client reconnecting...");
                    if (client.IsConnected)
                        client.ReconnectAsync();
                    else
                        client.ConnectAsync();
                    Console.WriteLine("Done!");
                    continue;
                }

                var commands = line.Split(' ');
                if (commands.Length < 2)
                {
                    Console.WriteLine("HTTP method and URL must be entered!");
                    continue;
                }

                if (commands[0].ToUpper() == "HEAD")
                {
                    var response = client.SendHeadRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "GET")
                {
                    var response = client.SendGetRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "POST")
                {
                    if (commands.Length < 3)
                    {
                        Console.WriteLine("HTTP method, URL and body must be entered!");
                        continue;
                    }

                    var response = client.SendPostRequest(commands[1], commands[2]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "PUT")
                {
                    if (commands.Length < 3)
                    {
                        Console.WriteLine("HTTP method, URL and body must be entered!");
                        continue;
                    }

                    var response = client.SendPutRequest(commands[1], commands[2]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "DELETE")
                {
                    var response = client.SendDeleteRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "OPTIONS")
                {
                    var response = client.SendOptionsRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "TRACE")
                {
                    var response = client.SendTraceRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else
                    Console.WriteLine("Unknown HTTP method");
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.Disconnect();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: HTTPS server
Here comes the example of the HTTPS cache server. It allows to manipulate
cache data with HTTP methods (GET, POST, PUT and DELETE) with secured
transport protocol.

Use the following link to open [Swagger OpenAPI](https://swagger.io/specification/) iterative documentation: https://localhost:8443/api/index.html

![OpenAPI-HTTPS](https://github.com/chronoxor/NetCoreServer/raw/master/images/openapi-https.png)

```c#
using System;
using System.Collections.Concurrent;
using System.Net;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using NetCoreServer;

namespace HttpsServer
{
    class CommonCache
    {
        public static CommonCache GetInstance()
        {
            if (_instance == null)
                _instance = new CommonCache();
            return _instance;
        }

        public string GetAllCache()
        {
            var result = new StringBuilder();
            result.Append("[\n");
            foreach (var item in _cache)
            {
                result.Append("  {\n");
                result.AppendFormat($"    \"key\": \"{item.Key}\",\n");
                result.AppendFormat($"    \"value\": \"{item.Value}\",\n");
                result.Append("  },\n");
            }
            result.Append("]\n");
            return result.ToString();
        }

        public bool GetCacheValue(string key, out string value)
        {
            return _cache.TryGetValue(key, out value);
        }

        public void PutCacheValue(string key, string value)
        {
            _cache[key] = value;
        }

        public bool DeleteCacheValue(string key, out string value)
        {
            return _cache.TryRemove(key, out value);
        }

        private readonly ConcurrentDictionary<string, string> _cache = new ConcurrentDictionary<string, string>();
        private static CommonCache _instance;
    }

    class HttpsCacheSession : HttpsSession
    {
        public HttpsCacheSession(NetCoreServer.HttpsServer server) : base(server) {}

        protected override void OnReceivedRequest(HttpRequest request)
        {
            // Show HTTP request content
            Console.WriteLine(request);

            // Process HTTP request methods
            if (request.Method == "HEAD")
                SendResponseAsync(Response.MakeHeadResponse());
            else if (request.Method == "GET")
            {
                string key = request.Url;

                // Decode the key value
                key = Uri.UnescapeDataString(key);
                key = key.Replace("/api/cache", "", StringComparison.InvariantCultureIgnoreCase);
                key = key.Replace("?key=", "", StringComparison.InvariantCultureIgnoreCase);

                if (string.IsNullOrEmpty(key))
                {
                    // Response with all cache values
                    SendResponseAsync(Response.MakeGetResponse(CommonCache.GetInstance().GetAllCache(), "application/json; charset=UTF-8"));
                }
                // Get the cache value by the given key
                else if (CommonCache.GetInstance().GetCacheValue(key, out var value))
                {
                    // Response with the cache value
                    SendResponseAsync(Response.MakeGetResponse(value));
                }
                else
                    SendResponseAsync(Response.MakeErrorResponse(404, "Required cache value was not found for the key: " + key));
            }
            else if ((request.Method == "POST") || (request.Method == "PUT"))
            {
                string key = request.Url;
                string value = request.Body;

                // Decode the key value
                key = Uri.UnescapeDataString(key);
                key = key.Replace("/api/cache", "", StringComparison.InvariantCultureIgnoreCase);
                key = key.Replace("?key=", "", StringComparison.InvariantCultureIgnoreCase);

                // Put the cache value
                CommonCache.GetInstance().PutCacheValue(key, value);

                // Response with the cache value
                SendResponseAsync(Response.MakeOkResponse());
            }
            else if (request.Method == "DELETE")
            {
                string key = request.Url;

                // Decode the key value
                key = Uri.UnescapeDataString(key);
                key = key.Replace("/api/cache", "", StringComparison.InvariantCultureIgnoreCase);
                key = key.Replace("?key=", "", StringComparison.InvariantCultureIgnoreCase);

                // Delete the cache value
                if (CommonCache.GetInstance().DeleteCacheValue(key, out var value))
                {
                    // Response with the cache value
                    SendResponseAsync(Response.MakeGetResponse(value));
                }
                else
                    SendResponseAsync(Response.MakeErrorResponse(404, "Deleted cache value was not found for the key: " + key));
            }
            else if (request.Method == "OPTIONS")
                SendResponseAsync(Response.MakeOptionsResponse());
            else if (request.Method == "TRACE")
                SendResponseAsync(Response.MakeTraceResponse(request.Cache));
            else
                SendResponseAsync(Response.MakeErrorResponse("Unsupported HTTP method: " + request.Method));
        }

        protected override void OnReceivedRequestError(HttpRequest request, string error)
        {
            Console.WriteLine($"Request error: {error}");
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"HTTPS session caught an error: {error}");
        }
    }

    class HttpsCacheServer : NetCoreServer.HttpsServer
    {
        public HttpsCacheServer(SslContext context, IPAddress address, int port) : base(context, address, port) {}

        protected override SslSession CreateSession() { return new HttpsCacheSession(this); }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"HTTPS server caught an error: {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // HTTPS server port
            int port = 8443;
            if (args.Length > 0)
                port = int.Parse(args[0]);
            // HTTPS server content path
            string www = "../../../../../www/api";
            if (args.Length > 1)
                www = args[1];

            Console.WriteLine($"HTTPS server port: {port}");
            Console.WriteLine($"HTTPS server static content path: {www}");
            Console.WriteLine($"HTTPS server website: https://localhost:{port}/api/index.html");

            Console.WriteLine();

            // Create and prepare a new SSL server context
            var context = new SslContext(SslProtocols.Tls12, new X509Certificate2("server.pfx", "qwerty"));

            // Create a new HTTP server
            var server = new HttpsCacheServer(context, IPAddress.Any, port);
            server.AddStaticContent(www, "/api");

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                }
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: HTTPS client
Here comes the example of the HTTPS client. It allows to send HTTP requests
(GET, POST, PUT and DELETE) and receive HTTP responses with secured
transport protocol.

```c#
using System;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using NetCoreServer;

namespace HttpsClient
{
    class Program
    {
        static void Main(string[] args)
        {
            // HTTPS server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // HTTPS server port
            int port = 8443;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"HTTPS server address: {address}");
            Console.WriteLine($"HTTPS server port: {port}");

            Console.WriteLine();

            // Create and prepare a new SSL client context
            var context = new SslContext(SslProtocols.Tls12, new X509Certificate2("client.pfx", "qwerty"), (sender, certificate, chain, sslPolicyErrors) => true);

            // Create a new HTTPS client
            var client = new HttpsClientEx(context, address, port);

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Reconnect the client
                if (line == "!")
                {
                    Console.Write("Client reconnecting...");
                    if (client.IsConnected)
                        client.ReconnectAsync();
                    else
                        client.ConnectAsync();
                    Console.WriteLine("Done!");
                    continue;
                }

                var commands = line.Split(' ');
                if (commands.Length < 2)
                {
                    Console.WriteLine("HTTP method and URL must be entered!");
                    continue;
                }

                if (commands[0].ToUpper() == "HEAD")
                {
                    var response = client.SendHeadRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "GET")
                {
                    var response = client.SendGetRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "POST")
                {
                    if (commands.Length < 3)
                    {
                        Console.WriteLine("HTTP method, URL and body must be entered!");
                        continue;
                    }

                    var response = client.SendPostRequest(commands[1], commands[2]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "PUT")
                {
                    if (commands.Length < 3)
                    {
                        Console.WriteLine("HTTP method, URL and body must be entered!");
                        continue;
                    }

                    var response = client.SendPutRequest(commands[1], commands[2]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "DELETE")
                {
                    var response = client.SendDeleteRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "OPTIONS")
                {
                    var response = client.SendOptionsRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else if (commands[0].ToUpper() == "TRACE")
                {
                    var response = client.SendTraceRequest(commands[1]).Result;
                    Console.WriteLine(response);
                }
                else
                    Console.WriteLine("Unknown HTTP method");
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.Disconnect();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: WebSocket chat server
Here comes the example of the WebSocket chat server. It handles multiple
WebSocket client sessions and multicast received message from any session
to all ones. Also it is possible to send admin message directly from the
server.

Use the following link to open WebSocket chat server example: http://localhost:8080/chat/index.html

![ws-chat](https://github.com/chronoxor/NetCoreServer/raw/master/images/ws-chat.png)

```c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
using NetCoreServer;

namespace WsChatServer
{
    class ChatSession : WsSession
    {
        public ChatSession(WsServer server) : base(server) {}

        public override void OnWsConnected(HttpRequest request)
        {
            Console.WriteLine($"Chat WebSocket session with Id {Id} connected!");

            // Send invite message
            string message = "Hello from WebSocket chat! Please send a message or '!' to disconnect the client!";
            SendTextAsync(message);
        }

        public override void OnWsDisconnected()
        {
            Console.WriteLine($"Chat WebSocket session with Id {Id} disconnected!");
        }

        public override void OnWsReceived(byte[] buffer, long offset, long size)
        {
            string message = Encoding.UTF8.GetString(buffer, (int)offset, (int)size);
            Console.WriteLine("Incoming: " + message);

            // Multicast message to all connected sessions
            ((WsServer)Server).MulticastText(message);

            // If the buffer starts with '!' the disconnect the current session
            if (message == "!")
                Close(1000);
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat WebSocket session caught an error with code {error}");
        }
    }

    class ChatServer : WsServer
    {
        public ChatServer(IPAddress address, int port) : base(address, port) {}

        protected override TcpSession CreateSession() { return new ChatSession(this); }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat WebSocket server caught an error with code {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // WebSocket server port
            int port = 8080;
            if (args.Length > 0)
                port = int.Parse(args[0]);
            // WebSocket server content path
            string www = "../../../../../www/ws";
            if (args.Length > 1)
                www = args[1];

            Console.WriteLine($"WebSocket server port: {port}");
            Console.WriteLine($"WebSocket server static content path: {www}");
            Console.WriteLine($"WebSocket server website: http://localhost:{port}/chat/index.html");

            Console.WriteLine();

            // Create a new WebSocket server
            var server = new ChatServer(IPAddress.Any, port);
            server.AddStaticContent(www, "/chat");

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                }

                // Multicast admin message to all sessions
                line = "(admin) " + line;
                server.MulticastText(line);
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: WebSocket chat client
Here comes the example of the WebSocket chat client. It connects to the
WebSocket chat server and allows to send message to it and receive new
messages.

```c#
using System;
using System.Net.Sockets;
using System.Text;
using System.Threading;
using NetCoreServer;

namespace WsChatClient
{
    class ChatClient : WsClient
    {
        public ChatClient(string address, int port) : base(address, port) {}

        public void DisconnectAndStop()
        {
            _stop = true;
            CloseAsync(1000);
            while (IsConnected)
                Thread.Yield();
        }

        public override void OnWsConnecting(HttpRequest request)
        {
            request.SetBegin("GET", "/");
            request.SetHeader("Host", "localhost");
            request.SetHeader("Origin", "http://localhost");
            request.SetHeader("Upgrade", "websocket");
            request.SetHeader("Connection", "Upgrade");
            request.SetHeader("Sec-WebSocket-Key", Convert.ToBase64String(WsNonce));
            request.SetHeader("Sec-WebSocket-Protocol", "chat, superchat");
            request.SetHeader("Sec-WebSocket-Version", "13");
            request.SetBody();
        }

        public override void OnWsConnected(HttpResponse response)
        {
            Console.WriteLine($"Chat WebSocket client connected a new session with Id {Id}");
        }

        public override void OnWsDisconnected()
        {
            Console.WriteLine($"Chat WebSocket client disconnected a session with Id {Id}");
        }

        public override void OnWsReceived(byte[] buffer, long offset, long size)
        {
            Console.WriteLine($"Incoming: {Encoding.UTF8.GetString(buffer, (int)offset, (int)size)}");
        }

        protected override void OnDisconnected()
        {
            base.OnDisconnected();

            Console.WriteLine($"Chat WebSocket client disconnected a session with Id {Id}");

            // Wait for a while...
            Thread.Sleep(1000);

            // Try to connect again
            if (!_stop)
                ConnectAsync();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat WebSocket client caught an error with code {error}");
        }

        private bool _stop;
    }

    class Program
    {
        static void Main(string[] args)
        {
            // WebSocket server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // WebSocket server port
            int port = 8080;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"WebSocket server address: {address}");
            Console.WriteLine($"WebSocket server port: {port}");

            Console.WriteLine();

            // Create a new TCP chat client
            var client = new ChatClient(address, port);

            // Connect the client
            Console.Write("Client connecting...");
            client.ConnectAsync();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Disconnect the client
                if (line == "!")
                {
                    Console.Write("Client disconnecting...");
                    client.DisconnectAsync();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Send the entered text to the chat server
                client.SendTextAsync(line);
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: WebSocket secure chat server
Here comes the example of the WebSocket secure chat server. It handles
multiple WebSocket secure client sessions and multicast received message
from any session to all ones. Also it is possible to send admin message
directly from the server.

This example is very similar to the WebSocket one except the code that
prepares WebSocket secure context and handshake handler.

Use the following link to open WebSocket secure chat server example: https://localhost:8443/chat/index.html

![wss-chat](https://github.com/chronoxor/NetCoreServer/raw/master/images/wss-chat.png)

```c#
using System;
using System.Net;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using NetCoreServer;

namespace WssChatServer
{
    class ChatSession : WssSession
    {
        public ChatSession(WssServer server) : base(server) {}

        public override void OnWsConnected(HttpRequest request)
        {
            Console.WriteLine($"Chat WebSocket session with Id {Id} connected!");

            // Send invite message
            string message = "Hello from WebSocket chat! Please send a message or '!' to disconnect the client!";
            SendTextAsync(message);
        }

        public override void OnWsDisconnected()
        {
            Console.WriteLine($"Chat WebSocket session with Id {Id} disconnected!");
        }

        public override void OnWsReceived(byte[] buffer, long offset, long size)
        {
            string message = Encoding.UTF8.GetString(buffer, (int)offset, (int)size);
            Console.WriteLine("Incoming: " + message);

            // Multicast message to all connected sessions
            ((WssServer)Server).MulticastText(message);

            // If the buffer starts with '!' the disconnect the current session
            if (message == "!")
                Close(1000);
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat WebSocket session caught an error with code {error}");
        }
    }

    class ChatServer : WssServer
    {
        public ChatServer(SslContext context, IPAddress address, int port) : base(context, address, port) {}

        protected override SslSession CreateSession() { return new ChatSession(this); }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat WebSocket server caught an error with code {error}");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            // WebSocket server port
            int port = 8443;
            if (args.Length > 0)
                port = int.Parse(args[0]);
            // WebSocket server content path
            string www = "../../../../../www/wss";
            if (args.Length > 1)
                www = args[1];

            Console.WriteLine($"WebSocket server port: {port}");
            Console.WriteLine($"WebSocket server static content path: {www}");
            Console.WriteLine($"WebSocket server website: https://localhost:{port}/chat/index.html");

            Console.WriteLine();

            // Create and prepare a new SSL server context
            var context = new SslContext(SslProtocols.Tls12, new X509Certificate2("server.pfx", "qwerty"));

            // Create a new WebSocket server
            var server = new ChatServer(context, IPAddress.Any, port);
            server.AddStaticContent(www, "/chat");

            // Start the server
            Console.Write("Server starting...");
            server.Start();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the server or '!' to restart the server...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Restart the server
                if (line == "!")
                {
                    Console.Write("Server restarting...");
                    server.Restart();
                    Console.WriteLine("Done!");
                }

                // Multicast admin message to all sessions
                line = "(admin) " + line;
                server.MulticastText(line);
            }

            // Stop the server
            Console.Write("Server stopping...");
            server.Stop();
            Console.WriteLine("Done!");
        }
    }
}
```

## Example: WebSocket secure chat client
Here comes the example of the WebSocket secure chat client. It connects to
the WebSocket secure chat server and allows to send message to it and receive
new messages.

This example is very similar to the WebSocket one except the code that
prepares WebSocket secure context and handshake handler.

```c#
using System;
using System.Net.Sockets;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading;
using NetCoreServer;

namespace WssChatClient
{
    class ChatClient : WssClient
    {
        public ChatClient(SslContext context, string address, int port) : base(context, address, port) {}

        public void DisconnectAndStop()
        {
            _stop = true;
            CloseAsync(1000);
            while (IsConnected)
                Thread.Yield();
        }

        public override void OnWsConnecting(HttpRequest request)
        {
            request.SetBegin("GET", "/");
            request.SetHeader("Host", "localhost");
            request.SetHeader("Origin", "http://localhost");
            request.SetHeader("Upgrade", "websocket");
            request.SetHeader("Connection", "Upgrade");
            request.SetHeader("Sec-WebSocket-Key", Convert.ToBase64String(WsNonce));
            request.SetHeader("Sec-WebSocket-Protocol", "chat, superchat");
            request.SetHeader("Sec-WebSocket-Version", "13");
            request.SetBody();
        }

        public override void OnWsConnected(HttpResponse response)
        {
            Console.WriteLine($"Chat WebSocket client connected a new session with Id {Id}");
        }

        public override void OnWsDisconnected()
        {
            Console.WriteLine($"Chat WebSocket client disconnected a session with Id {Id}");
        }

        public override void OnWsReceived(byte[] buffer, long offset, long size)
        {
            Console.WriteLine($"Incoming: {Encoding.UTF8.GetString(buffer, (int)offset, (int)size)}");
        }

        protected override void OnDisconnected()
        {
            base.OnDisconnected();

            Console.WriteLine($"Chat WebSocket client disconnected a session with Id {Id}");

            // Wait for a while...
            Thread.Sleep(1000);

            // Try to connect again
            if (!_stop)
                ConnectAsync();
        }

        protected override void OnError(SocketError error)
        {
            Console.WriteLine($"Chat WebSocket client caught an error with code {error}");
        }

        private bool _stop;
    }

    class Program
    {
        static void Main(string[] args)
        {
            // WebSocket server address
            string address = "127.0.0.1";
            if (args.Length > 0)
                address = args[0];

            // WebSocket server port
            int port = 8443;
            if (args.Length > 1)
                port = int.Parse(args[1]);

            Console.WriteLine($"WebSocket server address: {address}");
            Console.WriteLine($"WebSocket server port: {port}");

            Console.WriteLine();

            // Create and prepare a new SSL client context
            var context = new SslContext(SslProtocols.Tls12, new X509Certificate2("client.pfx", "qwerty"), (sender, certificate, chain, sslPolicyErrors) => true);

            // Create a new TCP chat client
            var client = new ChatClient(context, address, port);

            // Connect the client
            Console.Write("Client connecting...");
            client.ConnectAsync();
            Console.WriteLine("Done!");

            Console.WriteLine("Press Enter to stop the client or '!' to reconnect the client...");

            // Perform text input
            for (;;)
            {
                string line = Console.ReadLine();
                if (string.IsNullOrEmpty(line))
                    break;

                // Reconnect the client
                if (line == "!")
                {
                    Console.Write("Client reconnecting...");
                    if (client.IsConnected)
                        client.ReconnectAsync();
                    else
                        client.ConnectAsync();
                    Console.WriteLine("Done!");
                    continue;
                }

                // Send the entered text to the chat server
                client.SendTextAsync(line);
            }

            // Disconnect the client
            Console.Write("Client disconnecting...");
            client.DisconnectAndStop();
            Console.WriteLine("Done!");
        }
    }
}
```

# Performance

Here comes several communication scenarios with timing measurements.

Benchmark environment is the following:
```
CPU architecutre: Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz
CPU logical cores: 8
CPU physical cores: 4
CPU clock speed: 3.998 GHz
CPU Hyper-Threading: enabled
RAM total: 31.962 GiB
RAM free: 24.011 GiB

OS version: Microsoft Windows 8 Enterprise Edition (build 9200), 64-bit
OS bits: 64-bit
Process bits: 64-bit
Process configuaraion: release
```

## Benchmark: Round-Trip

![Round-trip](https://github.com/chronoxor/NetCoreServer/raw/master/images/round-trip.png)

This scenario sends lots of messages from several clients to a server.
The server responses to each message and resend the similar response to
the client. The benchmark measures total round-trip time to send all
messages and receive all responses, messages & data throughput, count
of errors.

### TCP echo server

* [TcpEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpEchoServer/Program.cs)
* [TcpEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpEchoClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 1111
Working clients: 1
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.024 s
Total data: 2.831 GiB
Total messages: 94369133
Data throughput: 287.299 MiB/s
Message latency: 106 ns
Message throughput: 9413997 msg/s
```

* [TcpEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpEchoServer/Program.cs)
* [TcpEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpEchoClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 1111
Working clients: 100
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.189 s
Total data: 1.794 GiB
Total messages: 59585544
Data throughput: 178.463 MiB/s
Message latency: 171 ns
Message throughput: 5847523 msg/s
```

### SSL echo server

* [SslEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslEchoServer/Program.cs)
* [SslEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslEchoClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 2222
Working clients: 1
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 2.645 s
Total data: 373.329 MiB
Total messages: 12233021
Data throughput: 141.095 MiB/s
Message latency: 216 ns
Message throughput: 4623352 msg/s
```

* [SslEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslEchoServer/Program.cs)
* [SslEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslEchoClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 2222
Working clients: 100
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.060 s
Total data: 1.472 GiB
Total messages: 49029133
Data throughput: 148.741 MiB/s
Message latency: 205 ns
Message throughput: 4873398 msg/s
```

### UDP echo server

* [UdpEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpEchoServer/Program.cs)
* [UdpEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpEchoClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 3333
Working clients: 1
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.032 s
Total data: 33.994 MiB
Total messages: 1113182
Data throughput: 3.395 MiB/s
Message latency: 9.012 mcs
Message throughput: 110960 msg/s
```

* [UdpEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpEchoServer/Program.cs)
* [UdpEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpEchoClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 3333
Working clients: 100
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.635 s
Total data: 20.355 MiB
Total messages: 666791
Data throughput: 1.934 MiB/s
Message latency: 15.950 mcs
Message throughput: 62693 msg/s
```

### Unix Domain Socket echo server

* [UdsEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsEchoServer/Program.cs)
* [UdsEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsEchoClient/Program.cs) --clients 1

```
Server Unix Domain Socket path: C:\Users\chronoxor\AppData\Local\Temp\echo.sock
Working clients: 1
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.016 s
Total data: 208.657 MiB
Total messages: 6836769
Data throughput: 20.850 MiB/s
Message latency: 1.465 mcs
Message throughput: 682575 msg/s
```

* [UdsEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsEchoServer/Program.cs)
* [UdsEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsEchoClient/Program.cs) --clients 100

```
Server Unix Domain Socket path: C:\Users\chronoxor\AppData\Local\Temp\echo.sock
Working clients: 100
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 12.253 s
Total data: 602.320 MiB
Total messages: 19736578
Data throughput: 49.157 MiB/s
Message latency: 620 ns
Message throughput: 1610666 msg/s
```

### Simple protocol server

* [ProtoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/ProtoServer/Program.cs)
* [ProtoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/ProtoClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 4444
Working clients: 1
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.015 s
Total data: 100.568 MiB
Total messages: 3294993
Data throughput: 10.040 MiB/s
Message latency: 3.039 mcs
Message throughput: 328978 msg/s
```

* [ProtoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/ProtoServer/Program.cs)
* [ProtoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/ProtoClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 4444
Working clients: 100
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 12.530 s
Total data: 207.994 MiB
Total messages: 6814785
Data throughput: 16.611 MiB/s
Message latency: 1.838 mcs
Message throughput: 543858 msg/s
```

### WebSocket echo server

* [WsEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsEchoServer/Program.cs)
* [WsEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsEchoClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 8080
Working clients: 1
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 3.037 s
Total data: 105.499 MiB
Total messages: 3456618
Data throughput: 34.742 MiB/s
Message latency: 878 ns
Message throughput: 1137864 msg/s
```

* [WsEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsEchoServer/Program.cs)
* [WsEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsEchoClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 8080
Working clients: 100
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.078 s
Total data: 426.803 MiB
Total messages: 13984888
Data throughput: 42.353 MiB/s
Message latency: 720 ns
Message throughput: 1387555 msg/s
```

### WebSocket secure echo server

* [WssEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssEchoServer/Program.cs)
* [WssEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssEchoClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 8443
Working clients: 1
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.030 s
Total data: 198.103 MiB
Total messages: 6491390
Data throughput: 19.767 MiB/s
Message latency: 1.545 mcs
Message throughput: 647153 msg/s
```

* [WssEchoServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssEchoServer/Program.cs)
* [WssEchoClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssEchoClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 8443
Working clients: 100
Working messages: 1000
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.112 s
Total data: 405.286 MiB
Total messages: 13280221
Data throughput: 40.078 MiB/s
Message latency: 761 ns
Message throughput: 1313228 msg/s
```

## Benchmark: Multicast

![Multicast](https://github.com/chronoxor/NetCoreServer/raw/master/images/multicast.png)

In this scenario server multicasts messages to all connected clients.
The benchmark counts total messages received by all clients for all
the working time and measures messages & data throughput, count
of errors.

### TCP multicast server

* [TcpMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpMulticastServer/Program.cs)
* [TcpMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpMulticastClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 1111
Working clients: 1
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.022 s
Total data: 407.023 MiB
Total messages: 13337326
Data throughput: 40.625 MiB/s
Message latency: 751 ns
Message throughput: 1330734 msg/s
```

* [TcpMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpMulticastServer/Program.cs)
* [TcpMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/TcpMulticastClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 1111
Working clients: 100
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.112 s
Total data: 421.348 MiB
Total messages: 13806493
Data throughput: 41.681 MiB/s
Message latency: 732 ns
Message throughput: 1365280 msg/s
```

### SSL multicast server

* [SslMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslMulticastServer/Program.cs)
* [SslMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslMulticastClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 2222
Working clients: 1
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.024 s
Total data: 325.225 MiB
Total messages: 10656801
Data throughput: 32.453 MiB/s
Message latency: 940 ns
Message throughput: 1063075 msg/s
```

* [SslMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslMulticastServer/Program.cs)
* [SslMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/SslMulticastClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 2222
Working clients: 100
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.144 s
Total data: 343.460 MiB
Total messages: 11254173
Data throughput: 33.876 MiB/s
Message latency: 901 ns
Message throughput: 1109393 msg/s
```

### UDP multicast server

* [UdpMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpMulticastServer/Program.cs)
* [UdpMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpMulticastClient/Program.cs) --clients 1

```
Server address: 239.255.0.1
Server port: 3333
Working clients: 1
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.026 s
Total data: 13.225 MiB
Total messages: 433202
Data throughput: 1.326 MiB/s
Message latency: 23.145 mcs
Message throughput: 43205 msg/s
```

* [UdpMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpMulticastServer/Program.cs)
* [UdpMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdpMulticastClient/Program.cs) --clients 100

```
Server address: 239.255.0.1
Server port: 3333
Working clients: 100
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.035 s
Total data: 28.684 MiB
Total messages: 939408
Data throughput: 2.877 MiB/s
Message latency: 10.682 mcs
Message throughput: 93606 msg/s
```

### Unix Domain Socket multicast server

* [UdsMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsMulticastServer/Program.cs)
* [UdsMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsMulticastClient/Program.cs) --clients 1

```
Server Unix Domain Socket path: C:\Users\chronoxor\AppData\Local\Temp\multicast.sock
Working clients: 1
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.015 s
Total data: 204.127 MiB
Total messages: 6688763
Data throughput: 20.390 MiB/s
Message latency: 1.497 mcs
Message throughput: 667869 msg/s
```

* [UdsMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsMulticastServer/Program.cs)
* [UdsMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/UdsMulticastClient/Program.cs) --clients 100

```
Server Unix Domain Socket path: C:\Users\chronoxor\AppData\Local\Temp\multicast.sock
Working clients: 100
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.033 s
Total data: 124.463 MiB
Total messages: 4078051
Data throughput: 12.413 MiB/s
Message latency: 2.460 mcs
Message throughput: 406451 msg/s
```

### WebSocket multicast server

* [WsMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsMulticastServer/Program.cs)
* [WsMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsMulticastClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 8080
Working clients: 1
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.048 s
Total data: 183.108 MiB
Total messages: 6000000
Data throughput: 18.228 MiB/s
Message latency: 1.674 mcs
Message throughput: 597121 msg/s
```

* [WsMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsMulticastServer/Program.cs)
* [WsMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WsMulticastClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 8080
Working clients: 100
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.227 s
Total data: 125.957 MiB
Total messages: 4126627
Data throughput: 12.320 MiB/s
Message latency: 2.478 mcs
Message throughput: 403466 msg/s
```

### WebSocket secure multicast server

* [WssMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssMulticastServer/Program.cs)
* [WssMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssMulticastClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 8443
Working clients: 1
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.034 s
Total data: 184.159 MiB
Total messages: 6034421
Data throughput: 18.359 MiB/s
Message latency: 1.662 mcs
Message throughput: 601338 msg/s
```

* [WssMulticastServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssMulticastServer/Program.cs)
* [WssMulticastClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/WssMulticastClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 8443
Working clients: 100
Message size: 32
Seconds to benchmarking: 10

Errors: 0

Total time: 10.171 s
Total data: 315.306 MiB
Total messages: 10331721
Data throughput: 30.1022 MiB/s
Message latency: 984 ns
Message throughput: 1015763 msg/s
```

## Benchmark: Web Server

### HTTP Trace server

* [HttpTraceServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpTraceServer/Program.cs)
* [HttpTraceClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpTraceClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 8080
Working clients: 1
Working messages: 1
Seconds to benchmarking: 10

Errors: 0

Total time: 10.023 s
Total data: 10.987 MiB
Total messages: 108465
Data throughput: 1.096 MiB/s
Message latency: 92.414 mcs
Message throughput: 10820 msg/s
```

* [HttpTraceServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpTraceServer/Program.cs)
* [HttpTraceClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpTraceClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 8080
Working clients: 100
Working messages: 1
Seconds to benchmarking: 10

Errors: 0

Total time: 10.085 s
Total data: 40.382 MiB
Total messages: 401472
Data throughput: 4.003 MiB/s
Message latency: 25.120 mcs
Message throughput: 39807 msg/s
```

### HTTPS Trace server

* [HttpsTraceServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpsTraceServer/Program.cs)
* [HttpsTraceClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpsTraceClient/Program.cs) --clients 1

```
Server address: 127.0.0.1
Server port: 8443
Working clients: 1
Working messages: 1
Seconds to benchmarking: 10

Errors: 0

Total time: 595.214 ms
Total data: 627.842 KiB
Total messages: 6065
Data throughput: 1.030 MiB/s
Message latency: 98.139 mcs
Message throughput: 10189 msg/s
```

* [HttpsTraceServer](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpsTraceServer/Program.cs)
* [HttpsTraceClient](https://github.com/chronoxor/NetCoreServer/blob/master/performance/HttpsTraceClient/Program.cs) --clients 100

```
Server address: 127.0.0.1
Server port: 8443
Working clients: 100
Working messages: 1
Seconds to benchmarking: 10

Errors: 0

Total time: 3.548 s
Total data: 17.948 MiB
Total messages: 179111
Data throughput: 5.052 MiB/s
Message latency: 19.813 mcs
Message throughput: 50471 msg/s
```

# OpenSSL certificates
In order to create OpenSSL based server and client you should prepare a set of
SSL certificates.

## Production
Depending on your project, you may need to purchase a traditional SSL
certificate signed by a Certificate Authority. If you, for instance,
want some else's web browser to talk to your WebSocket project, you'll
need a traditional SSL certificate.

## Development
The commands below entered in the order they are listed will generate a
self-signed certificate for development or testing purposes.

## Certificate Authority

* Create CA private key
```shell
openssl genrsa -passout pass:qwerty -out ca-secret.key 4096
```

* Remove passphrase
```shell
openssl rsa -passin pass:qwerty -in ca-secret.key -out ca.key
```

* Create CA self-signed certificate
```shell
openssl req -new -x509 -days 3650 -subj '/C=BY/ST=Belarus/L=Minsk/O=Example root CA/OU=Example CA unit/CN=example.com' -key ca.key -out ca.crt
```

* Convert CA self-signed certificate to PFX
```shell
openssl pkcs12 -export -passout pass:qwerty -inkey ca.key -in ca.crt -out ca.pfx
```

* Convert CA self-signed certificate to PEM
```shell
openssl pkcs12 -passin pass:qwerty -passout pass:qwerty -in ca.pfx -out ca.pem
```

## SSL Server certificate

* Create private key for the server
```shell
openssl genrsa -passout pass:qwerty -out server-secret.key 4096
```

* Remove passphrase
```shell
openssl rsa -passin pass:qwerty -in server-secret.key -out server.key
```

* Create CSR for the server
```shell
openssl req -new -subj '/C=BY/ST=Belarus/L=Minsk/O=Example server/OU=Example server unit/CN=server.example.com' -key server.key -out server.csr
```

* Create certificate for the server
```shell
openssl x509 -req -days 3650 -in server.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out server.crt
```

* Convert the server certificate to PFX
```shell
openssl pkcs12 -export -passout pass:qwerty -inkey server.key -in server.crt -out server.pfx
```

* Convert the server certificate to PEM
```shell
openssl pkcs12 -passin pass:qwerty -passout pass:qwerty -in server.pfx -out server.pem
```

## SSL Client certificate

* Create private key for the client
```shell
openssl genrsa -passout pass:qwerty -out client-secret.key 4096
```

* Remove passphrase
```shell
openssl rsa -passin pass:qwerty -in client-secret.key -out client.key
```

* Create CSR for the client
```shell
openssl req -new -subj '/C=BY/ST=Belarus/L=Minsk/O=Example client/OU=Example client unit/CN=client.example.com' -key client.key -out client.csr
```

* Create the client certificate
```shell
openssl x509 -req -days 3650 -in client.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out client.crt
```

* Convert the client certificate to PFX
```shell
openssl pkcs12 -export -passout pass:qwerty -inkey client.key -in client.crt -out client.pfx
```

* Convert the client certificate to PEM
```shell
openssl pkcs12 -passin pass:qwerty -passout pass:qwerty -in client.pfx -out client.pem
```

## Diffie-Hellman key exchange

* Create DH parameters
```shell
openssl dhparam -out dh4096.pem 4096
```