eap (event-based asynchronous pattern)

EAP/Server/Server.cs

@@ -0,0 +1,77 @@
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+
+namespace Server;
+
+internal class Server
+{
+	private static readonly int BUFFER_SIZE = 256;
+
+	static void Main(string[] args)
+	{
+		Socket serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
+		IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 20000);
+		serverSocket.Bind(endPoint);
+		serverSocket.Listen(100);
+
+		SocketAsyncEventArgs arg = new SocketAsyncEventArgs();
+		arg.Completed += AcceptCompleted;
+		bool pending = serverSocket.AcceptAsync(arg);
+		if (!pending)
+			AcceptCompleted(serverSocket, arg);
+
+		while (true)
+		{
+			Thread.Sleep(1000);
+		}
+	}
+
+	private static void AcceptCompleted(object? sender, SocketAsyncEventArgs e)
+	{
+		if (sender == null || e == null || e.AcceptSocket == null)
+			return;
+
+		Socket serverSocket = (Socket)sender;
+		Socket clientSocket = e.AcceptSocket;
+		Console.WriteLine(clientSocket.RemoteEndPoint);
+
+		e.AcceptSocket = null;
+		bool pending = serverSocket.AcceptAsync(e);
+		if (!pending)
+			AcceptCompleted(serverSocket, e);
+
+		SocketAsyncEventArgs arg = new SocketAsyncEventArgs();
+		arg.Completed += ReceiveCompleted;
+		byte[] buffer = new byte[BUFFER_SIZE];
+		arg.SetBuffer(buffer, 0, buffer.Length);
+
+		bool pending2 = clientSocket.ReceiveAsync(arg);
+		if (!pending2)
+			ReceiveCompleted(clientSocket, arg);
+	}
+
+	private static void ReceiveCompleted(object? sender, SocketAsyncEventArgs e)
+	{
+		if (sender == null || e == null)
+			return;
+
+		Socket clientSocket = (Socket)sender;
+		if (e.BytesTransferred < 1)
+		{
+			Console.WriteLine("Client is disconnected...");
+			clientSocket.Dispose();
+			e.Dispose();
+			return;
+		}
+
+		Console.WriteLine(Encoding.UTF8.GetString(e.Buffer));
+
+		byte[] buffer = new byte[BUFFER_SIZE];
+		e.SetBuffer(buffer, 0, buffer.Length);
+
+		bool pending = clientSocket.ReceiveAsync(e);
+		if (!pending)
+			ReceiveCompleted(clientSocket, e);
+	}
+}