Asp.Net Core WebSocket绑定

1.说明

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。

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);

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