学步园

Delphi6中的TServerSocket在线程阻塞模式(TThreadBlocking)下，OnRead/OnWrite事件的是在主线程中执行的，虽为多线程，实际效率不高。
故我们若需要利用TServerSocket来开发真正多线程的服务器，则需要写TServerClientThread的子类，在这个子类中，自行处理数据的接收与发送，而重写的的重点在ClientExecute方法。下面为代码描述了这种编程思路。

type
  TServerForm=class(TForm)
  ...
  private
    procedure  GetThread(Sender: TObject; ClientSocket: TServerClientWinSocket; var SocketThread: TServerClientThread);
  end;

type
  TMyServerClientThread=class(TServerClientThread)
  private
    function WaitForData(TimeOut:Integer):Boolean;
  protected
    procedure ClientExecute;override;
  end;

implementation

{ TMyServerClientThread }

function TMyServerClientThread.WaitForData(TimeOut: Integer): Boolean;
var
  FDSet:TFDSet;
  TimeVal:TTimeVal;
begin
  FD_ZERO(FDSet);
  FD_SET(ClientSocket.SocketHandle,FDSet);
  TimeVal.tv_sec:=TimeOut div 1000;
  TimeVal.tv_usec:=TimeOut mod 1000;
  Result:=select(0,@FDSet,nil,nil,@TimeVal)>0
end;

procedure TMyServerClientThread.ClientExecute;
var
  InputBuffer:TSockBuffer;
  iLen,iPos:Integer;
  sCmd:string;
  tmpBuf:string;
begin
  InputBuffer:=TSockBuffer.Create;
  try
    while not Terminated and ClientSocket.Connected do
    begin
      if WaitForData(500) and not Terminated then
      begin
        iLen:=ClientSocket.ReceiveLength;
        if iLen=0 then
        begin
          Break
        end else
        begin
          SetLength(tmpBuf,iLen);
          ClientSocket.ReceiveBuf(tmpBuf[1],iLen);
          InputBuffer.WriteBuffer(tmpBuf[1],iLen);
          iPos:=InputBuffer.Pos(EOL);
          if iPos>0 then
          begin
            sCmd:=InputBuffer.Extract(iPos+1);
            Delete(sCmd,Length(sCmd)-1,2);
            if CmdList.IndexOf(sCmd)>-1 then
              ClientSocket.SendText('+OK');
            if SameText(sCmd,'EXIT') then
              Break;
          end;
        end;
      end;
    end;
  finally
    InputBuffer.Free;
  end;
end;

{ TServerForm }

procedure TServerForm.FormCreate(Sender: TObject);
begin
  with TServerSocket.Create(Self) do
  begin
    Port:=4001;
    ServerType:=stThreadBlocking;
    OnGetThread:=GetThread; //这一步是关键，OnGetThread事件产生时，创建自己的线程。
    Active:=True;
  end;
end;

procedure TServerForm.GetThread(Sender: TObject;
  ClientSocket: TServerClientWinSocket;
  var SocketThread: TServerClientThread);
begin
  SocketThread:=TMyServerClientThread.Create(False,ClientSocket);
end;