[C#] 利用Keep-alive來保持Socket長連接,並偵測網路異常

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;     private Socket ListenSocket;     private IPEndPoint ServerIPEndPoint;     public ManualResetEvent BeginAccpetControl=new ManualResetEvent(false);     //==========================     private Boolean IsBeginAccept = true ;     public List<byte> Reply_Message = new List<byte>();     public ServerSocketObject()     {         string LocalIP = Dns.GetHostByName(Dns.GetHostName()).AddressList[0].ToString();         ServerIPEndPoint = new IPEndPoint(IPAddress.Parse(LocalIP), 2266);         ListenSocket = new Socket(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)     }     private byte[] KeepAlive(int onOff, 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;     }     public void BeginAccept()     {         while (IsBeginAccept)         {             BeginAccpetControl.Reset();             ListenSocket.BeginAccept(new AsyncCallback(BeginAcceptCallBack), ListenSocket);             BeginAccpetControl.WaitOne(); //等待Clinet...         }         //===================     }     private void 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();     }     private void 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 (int num = 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();         }     } }