Pascal (Lazarus/Delphi)

Async Accept Socket Connection

See more Socket/SSL/TLS Examples

Demonstrates how to get the connected client socket after accepting a connection asynchronously. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Task,
  Chilkat.Socket;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  listenSocket: TSocket;
  maxWaitMs: Integer;
  acceptTask: TTask;
  connectedClient: TSocket;

begin
  success := False;

  //  This example assumes the Chilkat Socket API to have been previously unlocked.
  //  See Socket Unlock Sample for sample code.

  listenSocket := TSocket.Create;

  //  Bind to a port and listen.
  //  This example will listen at port 5555 and allows for a backlog
  //  of 25 pending connection requests.
  success := listenSocket.BindAndListen(5555,25);
  if (success <> True) then
    begin
      WriteLn(listenSocket.LastErrorText);
      Exit;
    end;

  //  Start a background task to accept an incoming connection ...
  maxWaitMs := 20000;
  acceptTask := listenSocket.AcceptNextConnectionAsync(maxWaitMs);
  acceptTask.Run();

  //  ...
  //  ...
  //  ...

  //  Imagine at this point the task has completed successfully,
  //  and a connection was accepted.  Here's how to get the connected socket...
  connectedClient := TSocket.Create;
  success := connectedClient.LoadTaskResult(acceptTask);

  //  Here's how it works:  The AcceptNextConnection method would normally
  //  return a socket object when called synchronously.  When called asynchronously,
  //  it cannot do so because it returns the task object.  When the async method
  //  (running in a background thread) completes, the socket object that is the client
  //  connection is contained within the task object.
  //  
  //  This can be generalized for any case where a Chilkat method returns an object.
  //  The async version of that method is such that the object returned in the background
  //  thread is contained within the task object.

  //  To get the result object, we create a new object instance of that type.
  //  In this case, we create a socket object (connectedClient).  There is a LoadTaskResult
  //  method in all Chilkat classes that can be a return value of an async method call.
  //  The LoadTaskResult method transfers the returned object from the task to the caller.


  listenSocket.Free;
  connectedClient.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.