Delphi ActiveX

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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var
success: Integer;
mailman: TChilkatMailMan;

begin
success := 0;

//  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 := TChilkatMailMan.Create(Self);

//  Configure the SMTP server connection.
mailman.SmtpHost := 'smtp.example.com';
mailman.SmtpPort := 465;
mailman.SmtpSsl := 1;
mailman.SmtpUsername := 'user@example.com';
mailman.SmtpPassword := 'myPassword';

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

success := mailman.OpenSmtpConnection();
if (success = 0) then
  begin
    Memo1.Lines.Add(mailman.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('SMTP connection opened.');

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

//  Close the connection when done.
success := mailman.CloseSmtpConnection();
if (success = 0) then
  begin
    Memo1.Lines.Add(mailman.LastErrorText);
    Exit;
  end;