Websocket in .net core

You can try with below:

1. Install the required package:

dotnet add package System.Net.WebSockets

2. Update your code to use WebSockets:

using System;
using System.Net;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

class Program
{
    private static async Task StartListener()
    {
        HttpListener httpListener = new HttpListener();
        httpListener.Prefixes.Add("http://localhost:11000/");
        httpListener.Start();

        Console.WriteLine("Waiting for a connection...");

        while (true)
        {
            HttpListenerContext context = await httpListener.GetContextAsync();
            if (context.Request.IsWebSocketRequest)
            {
                HttpListenerWebSocketContext webSocketContext = await context.AcceptWebSocketAsync(null);
                Task.Run(() => HandleConnection(webSocketContext.WebSocket));
            }
            else
            {
                context.Response.StatusCode = 400;
                context.Response.Close();
            }
        }
    }

    private static async Task HandleConnection(WebSocket webSocket)
    {
        byte[] buffer = new byte[1024];
        WebSocketReceiveResult result = null;

        try
        {
            while (webSocket.State == WebSocketState.Open)
            {
                result = await webSocket.ReceiveAsync(new ArraySegment(buffer), CancellationToken.None);

                if (result.MessageType == WebSocketMessageType.Close)
                {
                    await webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closing", CancellationToken.None);
                }
                else
                {
                    string receivedMessage = Encoding.UTF8.GetString(buffer, 0, result.Count);
                    Console.WriteLine("Text received : {0}", receivedMessage);

                    string responseMessage = receivedMessage; // Echo back the same message
                    byte[] responseBuffer = Encoding.UTF8.GetBytes(responseMessage);
                    await webSocket.SendAsync(new ArraySegment(responseBuffer), WebSocketMessageType.Text, true, CancellationToken.None);
                }
            }
        }
        catch (Exception e)
        {
            Console.WriteLine(e.ToString());
        }
        finally
        {
            if (webSocket != null)
                webSocket.Dispose();
        }
    }

    public static void Main(string[] args)
    {
        Task listenerTask = StartListener();

        Console.WriteLine("Press ENTER to exit...");
        Console.ReadLine();
    }
}
 

Using a WebSocket client:

const socket = new WebSocket('ws://localhost:11000/');
socket.onopen = function (event) {
    socket.send('Hello Server! ');
};
socket.onmessage = function (event) {
    console.log('Message from server: ', event.data);
};
 

This setup allows you to listen to WebSocket connections and handle incoming messages. The messages are echoed back to the client, and the connection remains open until explicitly closed by the client or server.

@Sunny, Ok let me explore if i got something then will post here.

@Vikas Singh I want to listen to this by socket URL. 

The socket that has been created is in PHP using socket.io, and I need to listen to this socket in C#. Currently, there is no library like socket.io available in C#.

@Sunny, You can check below article to setup simple socket listener in .Net Core : 

https://www.c-sharpcorner.com/article/building-a-simple-socket-listener-in-net-core/

Here are a couple more C# Corner articles that might help.

Using WebSocket To Build Real-Time Application Via ASP.NET Core
https://www.c-sharpcorner.com/article/using-websocket-to-build-real-time-application-via-asp-net-core

How To Use WebSockets In ASP.NET Core - Day Nine
https://www.c-sharpcorner.com/article/how-to-use-websockets-in-asp-net-core-day-nine2

The following is a Microsoft sample.

WebSocket sample - Code Samples | Microsoft Learn
https://learn.microsoft.com/en-us/samples/microsoft/windows-universal-samples/websocket

And the following is in GitHub; it appears to be quite useful.

WebSocket-Samples/HttpListenerWebSocketEcho/Client/Client.cs at master · paulbatum/WebSocket-Samples
https://github.com/paulbatum/WebSocket-Samples/blob/master/HttpListenerWebSocketEcho/Client/Client.cs

Hi Sunny,

You using .net core in signalR concepts

Refer this Article 

https://www.c-sharpcorner.com/article/signalr-introduction-and-implementation-using-the-net-core-6-web-api-and-angula/