[C#] 利用Keep-alive來保持Socket長連接,並偵測網路異常

来源：互联网发布：js上传文件编辑：程序博客网时间：2024/06/05 10:57

今天工作時發現當Clinet端不正常斷線時, Server端竟然不知道!!!!

不知道Client端已經不存在了, 笨笨的繼續傳遞資料給Client(是我笨吧…Orz)

當然會導致程式發生Exception……….

Server真的會不知道嗎~~會他當然會知道但是預設為兩小時後[1]~這早就發生Exception…

經過[1]中發現, 原來可以設定 Keep-Alive來保持Socket長連接, 並且偵測網路異常拋出Exception

當Client端發生不正常斷線時, Server端將會立刻知道~~~

Keep-Alive使用方法寫在Comment裡嚕~ 這裡紀錄一下

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using System.Net.Sockets;
using System.Net;
public class ServerSocketObject
{
    public Socket ClientToServerSocket;
    privateSocket ListenSocket;
    privateIPEndPoint ServerIPEndPoint;
    publicManualResetEvent BeginAccpetControl=newManualResetEvent(false);
    //==========================
    privateBoolean IsBeginAccept = true;
    publicList<byte> Reply_Message =new List<byte>();
    publicServerSocketObject()
    {
        string LocalIP = Dns.GetHostByName(Dns.GetHostName()).AddressList[0].ToString();
        ServerIPEndPoint = newIPEndPoint(IPAddress.Parse(LocalIP), 2266); 
        ListenSocket = newSocket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        ListenSocket.Bind(ServerIPEndPoint);
        ListenSocket.Listen(1);  //ip pool 設為 1
        ListenSocket.IOControl(IOControlCode.KeepAliveValues, KeepAlive(1, 1000, 1000),null);  
        //將這個Socket使用<b style="background: rgb(255, 102, 255); color: rgb(0, 0, 0);">keep</b>-alive來保持長連線
        //KeepAlive函數參數說明: onOff:是否開啟<b style="background: rgb(255, 102, 255); color: rgb(0, 0, 0);">Keep</b>-Alive(開 1/ 關 0) ,
        //keepAliveTime:當開啟<b style="background: rgb(255, 102, 255); color: rgb(0, 0, 0);">keep</b>-Alive後經過多久時間(ms)開啟偵測
        //keepAliveInterval: 多久偵測一次(ms)
    }
    privatebyte[] KeepAlive(intonOff, int keepAliveTime, int keepAliveInterval)
    {
        byte[] buffer = new byte[12];
        BitConverter.GetBytes(onOff).CopyTo(buffer, 0);
        BitConverter.GetBytes(keepAliveTime).CopyTo(buffer, 4);
        BitConverter.GetBytes(keepAliveInterval).CopyTo(buffer, 8);
        return buffer;
    }
    publicvoid BeginAccept()
    {
        while (IsBeginAccept)
        {
            BeginAccpetControl.Reset();
            ListenSocket.BeginAccept(newAsyncCallback(BeginAcceptCallBack), ListenSocket);
            BeginAccpetControl.WaitOne(); //等待Clinet...
        }
        //===================
    }
    privatevoid BeginAcceptCallBack(IAsyncResult state)
    {
        Socket Listener = (Socket)state.AsyncState;
        ClientToServerSocket = Listener.EndAccept(state); //Client連線成功
        ClientToServerSocket.BeginReceive(buffer, 0, BufferSize, 0,new AsyncCallback(ReceivedCallBack), ClientToServerSocket); 
        //連線成功後 開始接收Server所傳遞的資料
        BeginAccpetControl.Set();
    }
    privatevoid ReceivedCallBack(IAsyncResult ar)
    {
        Socket state = (Socket)ar.AsyncState;
        if (state.Connected ==true)
        {
            try
            {
               int bytesRead = state.EndReceive(ar);
               if (bytesRead > 0)//當 bytesRead大於0時表示Server傳遞資料過來 等於0時代表Client"正常"斷線
               {
                   for (intnum = 0; num < bytesRead; num++)
                   {
                       Reply_Message.Add(buffer[num]); //收集資料
                   }
                   state.BeginReceive(buffer, 0, BufferSize, 0, new AsyncCallback(ReceivedCallBack), ClientToServerSocket);
               }
               else
               {
                   //處理Client端"正常"斷線的事件
               }
            }
            catch (Exception ee)
            {
               //這裡就是當設定好<b style="background: rgb(255, 102, 255); color: rgb(0, 0, 0);">Keep</b>-alive後, 假設Clinet端發生"不正常斷線(網路異常)"時, 將會
               //跑進來這個Exception裡,再加以處理
               state.Shutdown(SocketShutdown.Both);
               state.Close();
            }
        }
        else
        {
            IsConntect = false;
            state.Close();
        }
    }
}