Asp.Net Core中WebSocket绑定的方法详解

说明

Websocket是html5后的产物，对于asp.net core中也得到了支持，Asp.Net Core中WebScoket的操作使用基本上和Asp.net中相同，不同的是，绑定监听。
Asp.Net Core2.0默认已经支持WebSocket，不需要另外安装Nuget包。
通过对HttpContext中的WebSockets.AcceptWebSocketAsync方法，接受WebSocket请求；并返回WebScoket对象。
下面话不多说了，来一起看看详细的介绍吧。

一、示例1,

1.后台启动文件Startup的configure中绑定WebSocket的路由监听

public void Configure(IApplicationBuilder app, IHostingEnvironment env, IServiceProvider svp) 
{
    
     
...... 
 //绑定WebSocket 
 app.Map("/wsone/Connect", (con) => 
 {
    
     
  con.UseWebSockets(); 
  WSHanleTwo _two = new WSHanleTwo(); 
  con.Use(_two.Connect); 
 }); 
}

2.定义请求处理类

using System.Net.WebSockets; 
using System.Threading; 
using System.Threading.Tasks; 
namespace Core_Razor_2 
{
    
     
 public class WSHanleTwo 
 {
    
     
  private WebSocket socket = null; 
  //创建链接 
  public async Task Connect(HttpContext context, Func<Task> n) 
  {
    
     
   try
   {
    
     
    //执行接收 
    WebSocket socket = await context.WebSockets.AcceptWebSocketAsync(); 
    this.socket = socket; 
    //执行监听 
    await EchoLoop(); 
   } 
   catch (Exception ex) 
   {
    
     
    throw ex; 
   } 
  } 
  /// <summary> 
  /// 响应处理 
  /// </summary> 
  /// <returns></returns> 
  async Task EchoLoop() 
  {
    
     
   var buffer = new byte[1024]; 
   var seg = new ArraySegment<byte>(buffer); 
   while (this.socket.State == WebSocketState.Open) 
   {
    
     
    var incoming = await this.socket.ReceiveAsync(seg, CancellationToken.None); 
    byte[] backInfo = System.Text.UTF8Encoding.Default.GetBytes("服务端相应内容"); 
    var outgoing = new ArraySegment<byte>(backInfo, 0, incoming.Count); 
    await this.socket.SendAsync(outgoing, WebSocketMessageType.Text, true, CancellationToken.None); 
   } 
  } 
 } 
}

3.前台请求代码

var socket; 
//var uri = "ws://" + window.location.host + "/ws"; 
var uri = "ws://" + window.location.host + "@Url.Action("Connect")"; 
var output; 
var text = "test echo"; 
function write(s) {
    
     
 var p = document.createElement("p"); 
 p.innerHTML = s; 
 output.appendChild(p); 
} 
function doConnect() {
    
     
 socket = new WebSocket(uri); 
 socket.onopen = function (e) {
    
     write("opened " + uri); doSend(); }; 
 socket.onclose = function (e) {
    
     write("closed"); }; 
 socket.onmessage = function (e) {
    
     write("Received: " + e.data); socket.close(); }; 
 socket.onerror = function (e) {
    
     write("Error: " + e.data); }; 
} 
function doSend() {
    
     
 write("Sending: " + text); 
 socket.send(text); 
} 
function onInit() {
    
     
 output = document.getElementById("output"); 
 doConnect(); 
} 
window.onload = onInit;

二、为了简单绑定，可以这样封装

public class SocketHandler 
{
    
     
 public const int BufferSize = 4096; 
 WebSocket socket; 
 SocketHandler(WebSocket socket) 
 {
    
     
  this.socket = socket; 
 } 
 
 async Task EchoLoop() 
 {
    
     
  var buffer = new byte[BufferSize]; 
  var seg = new ArraySegment<byte>(buffer); 
  while (this.socket.State == WebSocketState.Open) 
  {
    
     
   var incoming = await this.socket.ReceiveAsync(seg, CancellationToken.None); 
   var outgoing = new ArraySegment<byte>(buffer, 0, incoming.Count); 
   await this.socket.SendAsync(outgoing, WebSocketMessageType.Text, true, CancellationToken.None); 
  } 
 } 
 
 static async Task Acceptor(HttpContext hc, Func<Task> n) 
 {
    
     
  if (!hc.WebSockets.IsWebSocketRequest) 
   return; 
  var socket = await hc.WebSockets.AcceptWebSocketAsync(); 
  var h = new SocketHandler(socket); 
  await h.EchoLoop(); 
 } 
 
 /// <summary> 
 /// 路由绑定处理 
 /// </summary> 
 /// <param name="app"></param> 
 public static void Map(IApplicationBuilder app) 
 {
    
     
  app.UseWebSockets(); 
  app.Use(SocketHandler.Acceptor); 
 } 
}

路由绑定：

//绑定websocket 
app.Map("/ws", SocketHandler.Map);