Try WebSocketServer csharp

syabuo — Wed, 15 Jan 2020 04:02:38 +0000

Introduction

Tried to implement a WebSocket server using C # and send push notifications to the browser.
Don't use IIS and use System.Net.WebSockets to implement.
Referred to MSDN Articles

Server Source

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace WebSocketServerSample02
{
    class Program
    {
        static void Main(string[] args)
        {
            Run();
            Console.ReadKey();
        }

        static async Task Run()
        {
            HttpListener s = new HttpListener();
            s.Prefixes.Add("http://IPアドレス:ポート番号/");
            s.Start();
            Console.WriteLine("サーバ起動");

            var hc = await s.GetContextAsync();
            if (!hc.Request.IsWebSocketRequest)
            {
                hc.Response.StatusCode = 400;
                hc.Response.Close();
                return;
            }
            var wsc = await hc.AcceptWebSocketAsync(null);
            var ws = wsc.WebSocket;
            for (int i = 0; i != 5; ++i)
            {
                await Task.Delay(2000);
                var response = "push_event " + DateTime.Now.ToLongTimeString();
                var buffer = Encoding.UTF8.GetBytes(response);
                var segment = new ArraySegment<byte>(buffer);
                await ws.SendAsync(segment, WebSocketMessageType.Text, true, CancellationToken.None);
            }
            await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "Done", CancellationToken.None);
        }
    }
}

Start HTTP server using HttpListener.
Wait for WebSocket connection receive request with GetContextAsync().
Refer to Request.IsWebSocketRequest and return status code 400 if not WebSocket connection.
Enable WebSocket connection with AcceptWebSocketAsync(null).

Send to client

            var ws = wsc.WebSocket;
            for (int i = 0; i != 5; ++i)
            {
                await Task.Delay(2000);
                var response = "push_event " + DateTime.Now.ToLongTimeString();
                var buffer = Encoding.UTF8.GetBytes(response);
                var segment = new ArraySegment<byte>(buffer);
                await ws.SendAsync(segment, WebSocketMessageType.Text, true, CancellationToken.None);
            }
            await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "Done", CancellationToken.None);

Store the value of "push_event current time" to the client in response.
Send to client with SendAsync.

Client Source

WebSocket.onmessage processing operates when data comes from the server.

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>WebSocketClient</title>
<script src="js/jquery-1.11.3.js"></script>
<script type="text/javascript">
    var webSocket;
    window.onload = function() {
        url = "http://IPアドレス:ポート番号/";
        webSocket = new WebSocket(url.replace("http://", "ws://").replace("https://", "wss://"));
        var messageArea = document.getElementById("messageArea");
        var appendMessage = function(value, color) {
            var messageElement = document.createElement("div");
            messageElement.style.color = color;
            messageElement.innerText = value;
            messageArea.insertBefore(messageElement, messageArea.firstChild);
        }
        webSocket.onopen = function() {
            appendMessage("Opened", "blue");
        }
        webSocket.onclose = function() {
            appendMessage("Closed", "red");
        }
        webSocket.onmessage = function(message) {
            var data = message.data;
            alert(data);
            appendMessage(data, "black");
        }
        webSocket.onerror = function(message) {
            appendMessage(message, "red");
        }
    }
</script>
</head>
<body>
    <div id="messageArea"></div>
</body>
</html

DEV Community: syabuo

Try WebSocketServer csharp

Introduction

Server Source

Send to client

Client Source