C#高性能大容量SOCKET并发（六）：超时Socket断开（守护线程）和心跳包

守护线程

在服务端版Socket编程需要处理长时间没有发送数据的Socket，需要在超时多长时间后断开连接，我们需要独立一个线程（DaemonThread）来轮询，在执行断开时，需要把Socket对象锁定，并调用CloseClientSocket来断开连接，具体处理代码如下：

namespace SocketAsyncSvr
{
    class DaemonThread : Object
    {
        private Thread m_thread;
        private AsyncSocketServer m_asyncSocketServer;

        public DaemonThread(AsyncSocketServer asyncSocketServer)
        {
            m_asyncSocketServer = asyncSocketServer;
            m_thread = new Thread(DaemonThreadStart);
            m_thread.Start();
        }

        public void DaemonThreadStart()
        {
            while (m_thread.IsAlive)
            {
                AsyncSocketUserToken[] userTokenArray = null;
                m_asyncSocketServer.AsyncSocketUserTokenList.CopyList(ref userTokenArray);
                for (int i = 0; i < userTokenArray.Length; i++)
                {
                    if (!m_thread.IsAlive)
                        break;
                    try
                    {
                        if ((DateTime.Now - userTokenArray[i].ActiveDateTime).Milliseconds > m_asyncSocketServer.SocketTimeOutMS) //超时Socket断开
                        {
                            lock (userTokenArray[i])
                            {
                                m_asyncSocketServer.CloseClientSocket(userTokenArray[i]);
                            }
                        }
                    }                    
                    catch (Exception E)
                    {
                        Program.Logger.ErrorFormat("Daemon thread check timeout socket error, message: {0}", E.Message);
                        Program.Logger.Error(E.StackTrace);
                    }
                }

                for (int i = 0; i < 60 * 1000 / 10; i++) //每分钟检测一次
                {
                    if (!m_thread.IsAlive)
                        break;
                    Thread.Sleep(10);
                }
            }
        }

        public void Close()
        {
            m_thread.Abort();
            m_thread.Join();
        }
    }
}

心跳包

有超时连接，相对应的需要设计心跳包，心跳包用来检测连接和维护连接状态，心跳包的原理是客户端发送一个包给服务器，服务器收到后发一个响应包给客户端，通过检测是否有返回来判断连接是否正常，心跳包实现放在BaseSocketProtocol.DoActive方法中。

        public bool DoActive()
        {
            m_outgoingDataAssembler.AddSuccess();
            return DoSendResult();
        }

具体由各个协议是否决定调用，如控制协议ControlSocketProtocol实现心跳协议如下：

        public override bool ProcessCommand(byte[] buffer, int offset, int count) //处理分完包的数据，子类从这个方法继承
        {
            ControlSocketCommand command = StrToCommand(m_incomingDataParser.Command);
            m_outgoingDataAssembler.Clear();
            m_outgoingDataAssembler.AddResponse();
            m_outgoingDataAssembler.AddCommand(m_incomingDataParser.Command);
            if (!CheckLogined(command)) //检测登录
            {
                m_outgoingDataAssembler.AddFailure(ProtocolCode.UserHasLogined, "");
                return DoSendResult();
            }
            if (command == ControlSocketCommand.Login)
                return DoLogin();
            else if (command == ControlSocketCommand.Active)
                return DoActive();
            else if (command == ControlSocketCommand.GetClients)
                return DoGetClients();
            else
            {
                Program.Logger.Error("Unknow command: " + m_incomingDataParser.Command);
                return false;
            }
        }

DEMO下载地址： http://download.youkuaiyun.com/detail/sqldebug_fan/7467745
免责声明：此代码只是为了演示C#完成端口编程，仅用于学习和研究，切勿用于商业用途。水平有限，C#也属于初学，错误在所难免，欢迎指正和指导。邮箱地址：fansheng_hx@163.com。