Pascal (Lazarus/Delphi)

Open a Persistent SMTP Connection

Demonstrates the Chilkat MailMan.OpenSmtpConnection method, which explicitly opens a connection to the SMTP server and authenticates if a username and password, OAuth2 token, or other applicable settings have been provided. This example opens the connection, notes where sending would occur, and closes it.

Background: By default, sending a single email opens a connection, sends, and closes it. When sending many messages, that per-message overhead adds up. Explicitly calling OpenSmtpConnection once, sending in a loop, then CloseSmtpConnection keeps a single authenticated session open for the whole batch — substantially faster and gentler on the server than reconnecting each time.

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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.MailMan;

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

procedure RunDemo;
var
  success: Boolean;
  mailman: TMailMan;

begin
  success := False;

  //  Demonstrates the MailMan.OpenSmtpConnection method, which explicitly opens a connection
  //  to the SMTP server and authenticates if credentials (or an OAuth2 token) have been
  //  provided.

  mailman := TMailMan.Create;

  //  Configure the SMTP server connection.
  mailman.SmtpHost := 'smtp.example.com';
  mailman.SmtpPort := 465;
  mailman.SmtpSsl := True;
  mailman.SmtpUsername := 'user@example.com';
  mailman.SmtpPassword := 'myPassword';

  //  Explicitly open (and authenticate) the SMTP connection.

  success := mailman.OpenSmtpConnection();
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;

  WriteLn('SMTP connection opened.');

  //  ... send one or more emails here ...

  //  Close the connection when done.
  success := mailman.CloseSmtpConnection();
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;


  mailman.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.