TIdTCPServer.OnExecute in a console application - delphi

Question

I need to write a Delphi 2009 application, which reads data from a socket. To do this, I need to write an event handler for the TIdTCPServer.OnExecute event.
I found lots of examples for implementing this in GUI applications, but I need to do it in a console application (without any windows).
How should I modify the code below in order to add an event handler (attach it to TCPServer), which prints every received message into the debug output?
unit ReceivingThreadUnit;
interface
uses
Classes,
IdTCPServer,
IdSocketHandle,
SysUtils,
Windows;
type
ReceivingThread = class(TThread)
private
TCPServer: TIdTCPServer;
public
procedure Run();
end;
implementation
procedure ReceivingThread.Run();
var
Bindings: TIdSocketHandles;
begin
TCPServer := TIdTCPServer.Create(nil);
//setup and start TCPServer
Bindings := TIdSocketHandles.Create(TCPServer);
try
with Bindings.Add do
begin
IP := '127.0.0.1';
Port := 9998;
end;
try
TCPServer.Bindings:=Bindings;
// Here I want to attach TCPServer to an OnExecute event handler
TCPServer.Active:=True;
except on E:Exception do
OutputDebugString(PChar(E.ToString));
end;
finally
Bindings.Free;
TCPServer.Free;
end;
TCPServer.Active := true;
end;
end.

Answer 1

As David said (but did not fully show), you need to declare a method in your thread class and then assign it to the OnExecute event.
On a side note, you should not be creating a TIdSocketHandles collection manually. Call Add() on the existing TIdTCPServer.Bindings collection instead.
Try this:
unit ReceivingThreadUnit;
interface
uses
Classes,
IdTCPServer,
IdSocketHandle,
IdContext,
SysUtils,
Windows;
type
ReceivingThread = class(TThread)
private
TCPServer: TIdTCPServer;
procedure ExecuteHandler(AContext: TIdContext);
public
procedure Run;
end;
implementation
procedure ReceivingThread.ExecuteHandler(AContext: TIdContext);
begin
//...
end;
procedure ReceivingThread.Run;
begin
//setup and start TCPServer
TCPServer := TIdTCPServer.Create(nil);
try
with TCPServer.Bindings.Add do
begin
IP := '127.0.0.1';
Port := 9998;
end;
TCPServer.OnExecute := ExecuteHandler;
try
TCPServer.Active := True;
except
on E: Exception do
OutputDebugString(PChar(E.ToString));
end;
while not Terminated do
Sleep(1000);
TCPServer.Active := False;
finally
TCPServer.Free;
end;
end;
end.
With that said, your receiveing thread is actually pretty redundant since TIdTCPServer is already multi-threaded, so you could alternatively just eliminate the thread class altogether:
program MyApp;
{$APPTYPE CONSOLE}
{$R *.res}
uses
Classes,
IdTCPServer,
IdSocketHandle,
IdContext,
SysUtils,
Windows;
type
TCPServerEvents = class
public
class procedure ExecuteHandler(AContext: TIdContext);
end;
class procedure TCPServerEvents.ExecuteHandler(AContext: TIdContext);
begin
//...
end;
var
TCPServer: TIdTCPServer;
begin
//setup and start TCPServer
TCPServer := TIdTCPServer.Create(nil);
try
with TCPServer.Bindings.Add do
begin
IP := '127.0.0.1';
Port := 9998;
end;
TCPServer.OnExecute := TCPServerEvents.ExecuteHandler;
try
TCPServer.Active := True;
except
on E: Exception do
OutputDebugString(PChar(E.ToString));
end;
while (not stop condition) do
Sleep(1000);
TCPServer.Active := False;
finally
TCPServer.Free;
end;
end.

Answer 2

You need to add an event handler to your class. And then connect it up:
TCPServer.OnExecute := Self.ExecuteHandler;