Asp.net webApi 通过WebSocket推送消息给客户端，搭建一个即是服务端又是客户端的服务
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2022-03-13 08:20:30
https://blog.csdn.net/IT_ziliang/article/details/96478794 WebSocket是一种在单个TCP连接上进行全双工通信的协议。WebSocket通...
https://blog.csdn.net/IT_ziliang/article/details/96478794
WebSocket是一种在单个TCP连接上进行全双工通信的协议。WebSocket通信协议于2011年被IETF定为标准RFC 6455，并由RFC7936补充规范。WebSocket API也被W3C定为标准。
WebSocket使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据。在WebSocket API中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输。
废话不多说了，直接手把手教你如何通信
1、首先新建一个UserController继承自ApiController，然后写一个get方法供外部去调用。方法上一定加上 [HttpGet]，代码如下
[HttpGet]
public HttpResponseMessage GetConnect(string clientName)
{
HttpContext.Current.AcceptWebSocketRequest(ProcessRequest); //在服务器端接受Web Socket请求，传入的函数作为Web Socket的处理函数，待Web Socket建立后该函数会被调用，在该函数中可以对Web Socket进行消息收发
return Request.CreateResponse(HttpStatusCode.SwitchingProtocols); //构造同意切换至Web Socket的Response.
}
///记录客户端
private static List<WebSocket> _sockets = new List<WebSocket>();
///接受信息和发送信息
public async Task ProcessRequest(AspNetWebSocketContext context)
{
try
{
var socket = context.WebSocket;//传入的context中有当前的web socket对象
_sockets.Add(socket);//此处将web socket对象加入一个静态列表中
//进入一个无限循环，当web socket close是循环结束
while (true)
{
var buffer = new ArraySegment<byte>(new byte[1024]);
var receivedResult = await socket.ReceiveAsync(buffer, CancellationToken.None);//对web socket进行异步接收数据
if (receivedResult.MessageType == WebSocketMessageType.Close)
{
await socket.CloseAsync(WebSocketCloseStatus.Empty, string.Empty, CancellationToken.None);//如果client发起close请求，对client进行ack
_sockets.Remove(socket);
break;
}
if (socket.State == System.Net.WebSockets.WebSocketState.Open)
{
string recvMsg = Encoding.UTF8.GetString(buffer.Array, 0, receivedResult.Count);
var recvBytes = Encoding.UTF8.GetBytes(recvMsg);
var sendBuffer = new ArraySegment<byte>(recvBytes);
foreach (var innerSocket in _sockets)//当接收到文本消息时，对当前服务器上所有web socket连接进行广播
{
if (innerSocket != socket)
{
await innerSocket.SendAsync(sendBuffer, WebSocketMessageType.Text, true, CancellationToken.None);
}
}
}
}
}
catch (Exception ex)
{
logger.Error(ex.Message);//lognet4日志记录
}
}
}
2、如何做一个有信息就发送给所有客户端尼？就是再写个方法当作客户端发送信息给服务端就可以了，不用服务端去时时轮询。代码如下 这个方法就写在同一个类中，直接调用就行
private readonly ClientWebSocket webSocket = new ClientWebSocket();
private readonly CancellationToken _cancellation = new CancellationToken();
///客户端发送消息
private async void SendMsg(object data)
{
try
{
await webSocket.ConnectAsync(new Uri("ws://localhost:8080/api/User?clientName=" + 123), _cancellation);
var sendBytes = ObjectToBytes(data);//发送的数据
var bsend = new ArraySegment<byte>(sendBytes);
await webSocket.SendAsync(bsend, WebSocketMessageType.Binary, true, _cancellation);
await webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, "1", _cancellation);
webSocket.Dispose();//记得一定要释放不然服务端还产生很多连接
}
catch (Exception ex)
{
logger.Error(ex.Message);//lognet4日志记录
}
}
3、网页版的客户端代码如下
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0"/>
<title></title>
<script src="https://ajax.aspnetcdn.com/ajax/jquery/jquery-1.11.3.min.js"></script>
<script>
var ws;
$().ready(function () {
$('#conn').click(function () {
ws = new WebSocket('ws://localhost:8080' + '/api/user?clientName='+'456');
$('#msg').append('<p>正在连接</p>');
ws.onopen = function () {
$('#msg').append('<p>已经连接</p>');
}
ws.onmessage = function (evt) {
$('#msg').append('<p>' + evt.data + '</p>');
}
ws.onerror = function (evt) {
$('#msg').append('<p>' + JSON.stringify(evt) + '</p>');
}
ws.onclose = function () {
$('#msg').append('<p>已经关闭</p>');
}
});
$('#close').click(function () {
ws.close();
});
$('#send').click(function () {
if (ws.readyState == WebSocket.OPEN) {
ws.send($("#to").val() + "|" + $('#content').val());
}
else {
$('#tips').text('连接已经关闭');
}
});
});
</script>
</head>
<body>
<div>
<input id="user" type="text" />
<input id="conn" type="button" value="连接" />
<input id="close" type="button" value="关闭"/><br />
<span id="tips"></span>
<input id="content" type="text" />
<input id="send" type="button" value="发送"/><br />
<input id="to" type="text" />目的用户
<div id="msg">
</div>
</div>
</body>
</html>
4、C#控制台客户端的代码如下
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
namespace WebSocketClient
{
class Program
{
static ClientWebSocket _webSocket = new ClientWebSocket();
static CancellationToken _cancellation = new CancellationToken();
static void Main(string[] args)
{
WebSocket();
Console.Read();
}
public static async void WebSocket()
{
try
{
//建立连接
var url = "ws://localhost:8080/api/User?clientName=" + 456;
await _webSocket.ConnectAsync(new Uri(url), _cancellation);
while (true)
{
var result = new byte[1024];
await _webSocket.ReceiveAsync(new ArraySegment<byte>(result), new CancellationToken());//接受数据
var str = Encoding.UTF8.GetString(result, 0, result.Length);
Console.WriteLine(str);//打印到控制台
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
}