Question

我写了一个小型客户端 - 服务器应用程序，它运行在两台或多台不同的机器上，用于重启/关闭。由于我对客户端 - 服务器应用程序比较陌生，所以我选择了About Delphi approach here。简而言之，我的服务器应用程序等待端口7676上的连接，将客户端添加到客户端列表然后什么也不做（稍后将实现关闭和重新启动过程）。但是，即使它是被动的，只需连接两个客户端，它就会占用高达90％的CPU。这是客户端代码，由TidTCPServer和TidAntiFreeze组成：

type
  PClient   = ^TClient;
  TClient   = record
    PeerIP      : string[15];            { Client IP address }
    HostName    : String[40];            { Hostname }
    Connected,                           { Time of connect }
    LastAction  : TDateTime;             { Time of last transaction }
    AContext      : Pointer;             { Pointer to thread }
  end;

[...]

procedure TForm1.StartServerExecute(Sender: TObject);
var
  Bindings: TIdSocketHandles;
begin

  //setup and start TCPServer
  Bindings := TIdSocketHandles.Create(TCPServer);
  try
    with Bindings.Add do
    begin
      IP := DefaultServerIP;
      Port := DefaultServerPort;
    end;
    try
      TCPServer.Bindings:=Bindings;
      TCPServer.Active:=True;
    except on E:Exception do
      ShowMessage(E.Message);
    end;
  finally
    Bindings.Free;
  end;
  //setup TCPServer

  //other startup settings
  Clients := TThreadList.Create;
  Clients.Duplicates := dupAccept;

  RefreshListDisplay;

  if TCPServer.Active then
  begin
    Protocol.Items.Add(TimeToStr(Time)+' Shutdown server running on ' + TCPServer.Bindings[0].IP + ':' + IntToStr(TCPServer.Bindings[0].Port));
  end;
end;

procedure TForm1.TCPServerConnect(AContext: TIdContext);
var
  NewClient: PClient;
begin
  GetMem(NewClient, SizeOf(TClient));

  NewClient.PeerIP      := AContext.Connection.Socket.Binding.PeerIP;
  NewClient.HostName    := GStack.HostByAddress(NewClient.PeerIP);
  NewClient.Connected   := Now;
  NewClient.LastAction  := NewClient.Connected;
  NewClient.AContext    := AContext;

  AContext.Data := TObject(NewClient);

  try
    Clients.LockList.Add(NewClient);
  finally
    Clients.UnlockList;
  end;

  Protocol.Items.Add(TimeToStr(Time)+' Connection from "' + NewClient.HostName + '" from ' + NewClient.PeerIP);
  RefreshListDisplay;
end;

procedure TForm1.TCPServerDisconnect(AContext: TIdContext);
var
  Client: PClient;
begin
  Client := PClient(AContext.Data);
  Protocol.Items.Add (TimeToStr(Time)+' Client "' + Client.HostName+'"' + ' disconnected.');
  try
    Clients.LockList.Remove(Client);
  finally
    Clients.UnlockList;
  end;
  FreeMem(Client);
  AContext.Data := nil;

  RefreshListDisplay;

end;

procedure TForm1.TCPServerExecute(AContext: TIdContext);
var
  Client : PClient;
  Command : string;
  //PicturePathName : string;
  ftmpStream : TFileStream;
begin
  if not AContext.Connection.Connected then
  begin
    Client := PClient(AContext.Data);
    Client.LastAction := Now;

    //Command := AContext.Connection.ReadLn;
    if Command = 'CheckMe' then
    begin
      {do whatever necessary in here}
    end;
  end;
end;

idTCPServer组件设置如下：ListenQueue：= 15，MaxConnections：= 0，TerminateWaitTime：5000。

我在这里做错了吗？我是否应采取不同的方法，以便同时支持约30-40个客户？

谢谢，鲍勃。

Answer 1

你的CPU工具挂钩的原因是因为你的OnExecute事件处理程序实际上没有做任何事情，所以每个连接线程都在有效地运行一个紧凑的循环，不会给等待CPU的其他线程带来CPU时间片时间。您需要在该事件处理程序中进行一个让步操作。一旦你实现了你的实际命令，你就会ReadLn()处理这个让步，但在你实现之前，你可以使用对IndySleep()的调用，例如：

procedure TForm1.TCPServerExecute(AContext: TIdContext); 
var 
  Client : PClient; 
  Command : string; 
  //PicturePathName : string; 
  ftmpStream : TFileStream; 
begin 
  Client := PClient(AContext.Data); 
  Client.LastAction := Now; 

  //Command := AContext.Connection.ReadLn; 
  IndySleep(10);
  //...
end;

现在，话虽如此，您的代码中还存在其他一些问题，例如误用TIdSocketHandles，线程安全问题等。请尝试使用此代码：

uses
  ..., IdContext, IdSync;

//...

type 
  PClient   = ^TClient; 
  TClient   = record 
    PeerIP      : String;            { Client IP address } 
    HostName    : String;            { Hostname } 
    Connected   : TDateTime;         { Time of connect } 
    LastAction  : TDateTime;         { Time of last transaction } 
    AContext    : TIdContext;        { Pointer to thread } 
  end; 

//...

procedure TForm1.StartServerExecute(Sender: TObject); 
begin 
  //setup and start TCPServer 
  TCPServer.Bindings.Clear;
  with TCPServer.Bindings.Add do 
  begin 
    IP := DefaultServerIP; 
    Port := DefaultServerPort; 
  end; 
  TCPServer.Active := True; 
  //setup TCPServer 

  //other startup settings 
  Protocol.Items.Add(TimeToStr(Time) + ' Shutdown server running on ' + TCPServer.Bindings[0].IP + ':' + IntToStr(TCPServer.Bindings[0].Port)); 
  RefreshListDisplay; 
end; 

procedue TForm1.RefreshListDisplay;
var
  List: TList;
  I: Integer;
  Client: PClient;
begin
  // clear display list as needed...
  List := TCPServer.Contexts.LockList;
  try
    for I := 0 to List.Count-1 do
    begin
      Client := PClient(TIdContext(List[I]).Data);
      if Client <> nil then
      begin
        // add Client to display list as needed..
      end;
    end;
  finally
    TCPServer.Contexts.UnlockList;
  end;
end;

type
  TProtocolNotify = class(TIdNotify)
  protected
    FStr: String;
    procedure DoNotify; override;
  public
    class procedure Add(const AStr: String);
  end;

procedure TProtocolNotify.DoNotify;
begin
  Form1.Protocol.Items.Add(FStr);
end;

class procedure TProtocolNotify.Add(const AStr: String);
begin
  with Create do
  begin
    FStr := AStr;
    Notify;
  end;
end;

type
  TRefreshListNotify = class(TIdNotify)
  protected
    procedure DoNotify; override;
  public
    class procedure Refresh;
  end;

procedure TRefreshListNotify.DoNotify;
begin
  Form1.RefreshListDisplay;
end;

class procedure TRefreshListNotify.Refresh;
begin
  Create.Notify;
end;

procedure TForm1.TCPServerConnect(AContext: TIdContext); 
var 
  NewClient: PClient; 
begin 
  GetMem(NewClient, SizeOf(TClient)); 
  try
    NewClient.PeerIP      := AContext.Connection.Socket.Binding.PeerIP; 
    NewClient.HostName    := GStack.HostByAddress(NewClient.PeerIP); 
    NewClient.Connected   := Now; 
    NewClient.LastAction  := NewClient.Connected; 
    NewClient.AContext    := AContext; 
    AContext.Data         := TObject(NewClient); 
  except
    FreeMem(NewClient);
    raise;
  end;

  TProtocolNotify.Add(TimeToStr(Time) + ' Connection from "' + NewClient.HostName + '" from ' + NewClient.PeerIP); 
  TRefreshListNotify.Refresh;
end; 

procedure TForm1.TCPServerDisconnect(AContext: TIdContext); 
var 
  Client: PClient; 
begin 
  Client := PClient(AContext.Data); 
  TProtocolNotify.Add(TimeToStr(Time) + ' Client "' + Client.HostName+'"' + ' disconnected.'); 
  FreeMem(Client); 
  AContext.Data := nil; 
  TRefreshListNotify.Refresh; 
end; 

procedure TForm1.TCPServerExecute(AContext: TIdContext); 
var 
  Client : PClient; 
  Command : string; 
  //PicturePathName : string; 
  ftmpStream : TFileStream; 
begin 
  Client := PClient(AContext.Data); 
  Client.LastAction := Now; 

  //Command := AContext.Connection.ReadLn; 
  IndySleep(10);

  if Command = 'CheckMe' then 
  begin 
    {do whatever necessary in here} 
  end; 
end;

Answer 2

在TCPServerExecute()中，您没有初始化Command。

你不应该在Bindings中释放StartServerExecute()。而是尝试这样的事情：

var
  sh: TidSocketHandle;
begin
  sh := TCPServer.Bindings.Add;
  sh.IP := DefaultServerIP;
  sh.Port := DefaultServerPort;

什么是StartServerExecute()？

不幸的是，代码存在太多问题，并且缺少太多代码来猜测发生了什么。

Indy 10 + Delphi客户端 - 服务器应用程序占用所有CPU

2 个答案: