Delphi之TClientSocket和TServerSocket使用tcp keepalive心跳机制实现“断网”、"断电"检测...-白红宇

Delphi之TClientSocket和TServerSocket使用tcp keepalive心跳机制实现“断网”、"断电"检测...

阅读量：5173 次

发布时间：2019-06-13

本文共 1646 字，大约阅读时间需要 5 分钟。

开发环境：Delphi7

测试环境：WinXP，Win7 32bit，Win7 64bit

使用TClientSocket和TServerSocket实现TCP长连接通讯，经常因为断电断网等原因导致出现一些死连接。

解决方法是客户端和服务端都定时发送心跳包。

具体实现如下：

TClientSocket和TServerSocket均使用非阻塞模式

1、定义心跳常量和KeepAlive 数据结构

//定义心跳常量Const  IOC_IN = $80000000;  IOC_VENDOR = $18000000;  IOC_out = $40000000;  SIO_KEEPALIVE_VALS = IOC_IN or IOC_VENDOR or 4;  DATA_BUFSIZE = 8192;//定义 KeepAlive 数据结构Type  TTCP_KEEPALIVE = packed record    onoff: integer;    keepalivetime: integer;    keepaliveinterval: integer;  end;

2、引用WinSock,WinSock2

3、写一个方法来使用setsockopt，WSAIoctl设置心跳包参数

procedure TForm1.setKeepAlive(Socket: TCustomWinSocket);var  opt:Integer;  klive, outKlive: TTCP_KEEPALIVE;  i,j:integer;  OptVal: DWORD;begin  opt := 1;  //需引用WinSock.pas  if setsockopt(Socket.SocketHandle,SOL_SOCKET, SO_KEEPALIVE, PAnsiChar(@opt), SizeOf(opt)) = SOCKET_ERROR then  begin    showInfo(Format('WinSock Error %d', [WSAGetLastError()]));  end;  klive.onoff := 1;  klive.keepalivetime := 5000;  klive.keepaliveinterval := 1;  //需引用WinSock2.pas  if WSAIoctl(Socket.SocketHandle, SIO_KEEPALIVE_VALS, PAnsiChar(@klive),           SizeOf(TTCP_KEEPALIVE), PAnsiChar(@outKlive),           SizeOf(TTCP_KEEPALIVE), @opt,0,nil) = SOCKET_ERROR then  begin    showInfo(Format('WinSock Error %d', [WSAGetLastError()]));  end;end;

4、在TClientSocket和TServerSocket的连接事件中调用设置心跳

procedure TForm1.ServerSocket1ClientConnect(Sender: TObject;  Socket: TCustomWinSocket);begin  showInfo('ServerSocket1ClientConnect-' + Socket.RemoteAddress + ':' + IntToStr(Socket.RemotePort));  setKeepAlive(Socket); //设置socket心跳，以便清除死链接end;

经测试，采用以上方法，可以检测到把网线断网情况

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测试效果图：