客户端断开连接时如何检测关闭的TCP连接？ [英] How to detect closed TCP connection when client disconnected disgracfully ?

问题描述

How to detect closed TCP connection when Client disconnected disgracfully i.e sudden power off ?

以下方法当客户断断续续地断开连接时工作。



我尝试过：

Following method don't work when client disconnects disgracefully.

What I have tried:

<pre>if (socket != null)
                    {
                        bool part1 = socket.Poll(1000, SelectMode.SelectRead);
                        bool part2 = (socket.Available == 0);
                        if (part1 && part2)
                        {
                            return false;
                        }
                        else
                        {
                            return true;
                        }
                    }
                    else
                        return false;

推荐答案

TCP keepalive

这些看起来很有希望，在 .net中回答3 - 即时检测客户端断开服务器套接字 - 堆栈溢出 [ ^ ]



以及此处： http://tldp.org/HOWTO/TCP-Keepalive-HOWTO/overview.html [ ^ ]



我希望它有所帮助。

TCP keepalive
These looks promising, answer 3 in .net - Instantly detect client disconnection from server socket - Stack Overflow[^]

and also here: http://tldp.org/HOWTO/TCP-Keepalive-HOWTO/overview.html[^]

I hope it helps.

我使用过这样的东西：

I used something like this:

bool connectedLocal = true;

using (var socketTemp = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
 {
     socketTemp.Connect(ip, port);

     // Loop until prg finished or connection is lost.
     while (Running && connectedLocal)
     {
         Thread.CurrentThread.Join(100);
         connectedLocal = !(socketTemp.Poll(0, SelectMode.SelectRead) && socketTemp.Available == 0);
     }

     socketTemp.Close();
}

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