How to track number of clients with Indy TIdTCPServer

Question

I want to know the number of current client connections to an Indy 9 TIdTCPServer (on Delphi 2007)

I can\'t seem to find a property that gives this.

I\'ve tr

Answer 1

This should work on Indy 9, but it is pretty outdated nowadays, and maybe something is broken in your version, try to update to the latest Indy 9 available.

I made a simple test using Indy 10, which works very well with a simple interlocked Increment/Decrement in the OnConnect/OnDisconnect event handlers. This is my code:

//closes and opens the server, which listens at port 1025, default values for all properties
procedure TForm2.Button1Click(Sender: TObject);
begin
  IdTCPServer1.Active := not IdTCPServer1.Active;
  UpdateUI;
end;

procedure TForm2.FormCreate(Sender: TObject);
begin
  UpdateUI;
end;

//Just increment the count and update the UI
procedure TForm2.IdTCPServer1Connect(AContext: TIdContext);
begin
  InterlockedIncrement(FClientCount);
  TThread.Synchronize(nil, UpdateUI);
end;

//Just decrement the count and update the UI
procedure TForm2.IdTCPServer1Disconnect(AContext: TIdContext);
begin
  InterlockedDecrement(FClientCount);
  TThread.Synchronize(nil, UpdateUI);
end;

//Simple 'X' reply to any character, A is the "command" to exit
procedure TForm2.IdTCPServer1Execute(AContext: TIdContext);
begin
  AContext.Connection.IOHandler.Writeln('Write anything, but A to exit');
  while AContext.Connection.IOHandler.ReadByte <> 65 do
    AContext.Connection.IOHandler.Write('X');
  AContext.Connection.IOHandler.Writeln('');
  AContext.Connection.IOHandler.Writeln('Good Bye');
  AContext.Connection.Disconnect;
end;

//Label update with server status and count of connected clients 
procedure TForm2.UpdateUI;
begin
  Label1.Caption := Format('Server is %s, %d clients connected', [
    IfThen(IdTCPServer1.Active, 'Open', 'Closed'), FClientCount]);
end;

then, opening a couple of clients with telnet:

then, closing one client

That's it.

INDY 10 is available for Delphi 2007, my main advise is to upgrade anyway.