using System;

using System.Net;

using System.Net.Sockets;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

​

namespace HTTPServer2

{

    public class HttpServer

    {

        private readonly IPAddress ipAddress;

        private readonly int port;

        private readonly TcpListener tcpListener;

​

        public HttpServer(string ipAddress, int port)

        {

            this.ipAddress = IPAddress.Parse(ipAddress);

            this.port = port;

            this.tcpListener = new TcpListener(this.ipAddress, port);

        }

​

        public async Task Start()

        {

            this.tcpListener.Start();

            Console.WriteLine($"Server started on port {this.port}");

​

            while (true)

            {

                var tcpClient = await this.tcpListener.AcceptTcpClientAsync();

                _ = ProcessClientAsync(tcpClient);

            }

        }

​

        private async Task ProcessClientAsync(TcpClient tcpClient)

        {

            var networkStream = tcpClient.GetStream();

            var request = await this.ReadRequest(networkStream);

​

            Console.WriteLine(request);

​

            await WriteResponse(networkStream);

​

            tcpClient.Close();

        }

​

        private async Task<string> ReadRequest(NetworkStream networkStream)

        {

            var bufferSize = 1024;

            var buffer = new byte[bufferSize];

​

            var requestText = new StringBuilder();

​

            while (true)

            {

                if (!networkStream.DataAvailable)

                {

                    break;

                }

                var bytesRead = networkStream.Read(buffer, 0, bufferSize);

                requestText.Append(Encoding.UTF8.GetString(buffer, 0, bytesRead));

            }

​

            return requestText.ToString();

        }

​

        private async Task WriteResponse(NetworkStream networkStream)

        {

            var content = "Hello World!";

            var contentLength = Encoding.UTF8.GetByteCount(content);

​

            var response = $"HTTP/1.1 200 OK\r\n";

            response += "Server: My Web Server\r\n";

            response += $"Date: {DateTime.UtcNow.ToString("r")}\r\n";

            response += $"Content-Length: {contentLength}\r\n";

            response += "Content-Type: text/plain; charset=UTF-8\r\n\r\n";

            response += content;

​

            var responseBytes = Encoding.UTF8.GetBytes(response);

            await networkStream.WriteAsync(responseBytes);

        }

​

    }

}