使用SuperWebSocket實現Web消息推送

　　在大部分Web系統中，我們可能遇到需要向客戶端推送消息的需求。SuperWebSocket第三方庫能讓我們輕松的完成任務。SuperWebSocket第三方庫可以從網上下載，不過通過Visual Studio Nuget安裝更快。

引用SuperWebSocket相關組件后，在項目中添加WebSocketManager類

using SuperWebSocket;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

namespace WebSocketDemo
{
    public static class WebSocketManager
    {
        static Dictionary<string, WebSocketSession> sessionDics = new Dictionary<string, WebSocketSession>();
        static WebSocketServer webSocketServer;
        public static void Init()
        {
            var ip = GetLocalIP();
            webSocketServer = new WebSocketServer();

            var isSetup = webSocketServer.Setup(ip, 2019);
            Common.LogHelper.WriteError("WebSocketManager： 服務器端啟動" + (isSetup ? "成功" : "失敗"));
            if (!isSetup)
                return;

            webSocketServer.NewSessionConnected += WebSocketServer_NewSessionConnected;
            webSocketServer.SessionClosed += WebSocketServer_SessionClosed;
            webSocketServer.NewMessageReceived += WebSocketServer_NewMessageReceived;

            var isStart = webSocketServer.Start();
            Common.LogHelper.WriteError("WebSocketManager： 服務器端偵聽" + (isStart ? "成功" : "失敗"));
        }

        /// <summary>
        /// 接收消息
        /// </summary>
        /// <param name="session"></param>
        /// <param name="value"></param>
        private static void WebSocketServer_NewMessageReceived(WebSocketSession session, string value)
        {
            Common.LogHelper.WriteError("WebSocketManager： 接收消息 \r\n" + value);

            if (!string.IsNullOrWhiteSpace(value))
            {
                if (!sessionDics.ContainsKey(value))
                    sessionDics.Add(value, session);
                else
                    sessionDics[value] = session;

            }
        }

        /// <summary>
        /// 下線
        /// </summary>
        /// <param name="session"></param>
        /// <param name="value"></param>
        private static void WebSocketServer_SessionClosed(WebSocketSession session, SuperSocket.SocketBase.CloseReason value)
        {
            Common.LogHelper.WriteError(string.Format("WebSocketManager：{0} {1}下線", value, session.RemoteEndPoint));
        }

        /// <summary>
        /// 上線
        /// </summary>
        /// <param name="session"></param>
        private static void WebSocketServer_NewSessionConnected(WebSocketSession session)
        {
            Common.LogHelper.WriteError(string.Format("WebSocketManager：{0}上線",session.RemoteEndPoint));
        }

        /// <summary>
        /// 發送消息到客戶端
        /// </summary>
        /// <param name="value"></param>
        /// <param name="msg"></param>
        public static void SendMsgToRemotePoint(string value, string msg)
        {
            if (sessionDics.ContainsKey(value))
            {
                var webSocketSession = sessionDics[value];
                if (webSocketSession != null)
                {
                    webSocketSession.Send(msg);
                }
            }
        }


        /// <summary>
        /// 獲取本地IP等信息
        /// </summary>
        /// <returns></returns>
        public static string GetLocalIP()
        {
            //本機IP地址 
            string strLocalIP = "";
            //得到計算機名 
            string strPcName = Dns.GetHostName();
            //得到本機IP地址數組 
            IPHostEntry ipEntry = Dns.GetHostEntry(strPcName);
            //遍歷數組 
            foreach (var IPadd in ipEntry.AddressList)
            {
                //判斷當前字符串是否為正確IP地址 
                if (IsRightIP(IPadd.ToString()))
                {
                    //得到本地IP地址 
                    strLocalIP = IPadd.ToString();
                    //結束循環 
                    break;
                }
            }

            //返回本地IP地址 
            return strLocalIP;
        }
        /// <summary>
        /// 判斷是否為正確的IP地址
        /// </summary>
        /// <param name="strIPadd">需要判斷的字符串</param>
        /// <returns>true = 是 false = 否</returns>
        private static bool IsRightIP(string strIPadd)
        {
            //利用正則表達式判斷字符串是否符合IPv4格式
            if (Regex.IsMatch(strIPadd, "[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}"))
            {
                //根據小數點分拆字符串
                string[] ips = strIPadd.Split('.');
                if (ips.Length == 4 || ips.Length == 6)
                {
                    //如果符合IPv4規則
                    if (System.Int32.Parse(ips[0]) < 256 && System.Int32.Parse(ips[1]) < 256 & System.Int32.Parse(ips[2]) < 256 & System.Int32.Parse(ips[3]) < 256)
                        //正確
                        return true;
                    //如果不符合
                    else
                        //錯誤
                        return false;
                }
                else
                    //錯誤
                    return false;
            }
            else
                //錯誤
                return false;
        }
    }
}

在Global.asax.cs下初始化WebSocket，並啟動。

 public class WebApiApplication : System.Web.HttpApplication
 {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            GlobalConfiguration.Configure(WebApiConfig.Register);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);

            WebSocketManager.Init();
        }
  }

前端連接服務端WebSocket，打開網頁調用此js方法，就可以和服務端建立長連接通信。

WebSocketConnent(){
    var ip= localStorage.getItem("IP");//服務端的IP
    var openId= localStorage.getItem("kmWechatOpenId");//value
    var url="ws://"+ip+":2019";
    var ws;
    if ("WebSocket" in window) {
        ws = new WebSocket(url);
    }
    else if ("MozWebSocket" in window) {
        ws = new MozWebSocket(url);
    }
    else{
      console.log("WebSocketConnent","瀏覽器版本過低，請升級您的瀏覽器")
    }

    //注冊各類回調
    ws.onopen = function () {
        ws.send(openId);//服務端WebSocketServer_NewMessageReceived 接收到消息
      console.log("WebSocketConnent","連接服務器成功");
    }

    ws.onclose = function () {
      console.log("WebSocketConnent","與服務器斷開連接");
    }
    ws.onerror = function () {
      console.log("WebSocketConnent","數據傳輸發生錯誤");
    }
    ws.onmessage = function (receiveMsg) {
      localStorage.removeItem("token");//服務端SendMsgToRemotePoint 發送消息后接收

      console.log("WebSocketConnent","服務器推送過來的消息："+receiveMsg.data);
    }
  },