(Delphi ActiveX) Send DKIM Signed Email

Demonstrates how to create a simple email, add a DKIM signature, and send it.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
mailman: TChilkatMailMan;
dkim: TChilkatDkim;
email: TChilkatEmail;
success: Integer;
mimeData: Array of Byte;
password: WideString;
privKey: TPrivateKey;
dkimSignedMime: Array of Byte;
strFrom: WideString;
strTo: WideString;

begin
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// The mailman object is used for sending and receiving email.
mailman := TChilkatMailMan.Create(Self);

// The dkim object is used for creating the DKIM signature.
dkim := TChilkatDkim.Create(Self);

// Set the SMTP server.
mailman.SmtpHost := 'smtp.chilkatsoft.com';

// Set the SMTP login/password (if required)
mailman.SmtpUsername := 'myUsername';
mailman.SmtpPassword := 'myPassword';
// Set the SmtpPort if your SMTP server uses an alternative port (default = 25)
mailman.SmtpPort := 587;

// Create a new email object
email := TChilkatEmail.Create(Self);

email.Subject := 'This is a test';
email.Body := 'This is a test';
email.From := 'Chilkat Support <support@chilkatsoft.com>';
// We'll send the email to a Yahoo email account.  It is then
// possible to view the full headers within the Yahoo email
// interface to see if the DKIM signature was accepted.
success := email.AddTo('Chilkat Software','chilkat_software@yahoo.com');
success := email.AddTo('Chilkat Admin','admin@chilkatsoft.com');

// When sending an email with a DKIM signature, the MIME
// of the email must not be modified (in significant ways) prior to
// or during the sending process.  Therefore, the MIME of the
// email is assembled, the DKIM signature is added, and then
// SendMimeBytes is called to send the email.

// Get the MIME of the email.  Calling RenderToMimeBytes 
// causes the email to be signed and/or encrypted if those options
// have been selected.  The MIME returned by RenderToMimeBytes
// is the exact MIME that would've been sent if SendEmail was
// called.  We'll add a DKIM signature header to this MIME and then send...

mimeData := mailman.RenderToMimeBytes(email.ControlInterface);
if (mailman.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(mailman.LastErrorText);
    Exit;
  end;

// To create a DKIM signature for email (i.e. MIME),
// you'll need to provide the following:
// (1) An RSA private key in any common file format.
// (2) The domain name (typically the same domain
// as the sender of an email).
// (3) A selector for the domain name -- an arbitrary string
// to identify the matching public key in DNS.

// To allow an email recipient to verify the DKIM signature via an
// external email client supporting DKIM or using other software,
// you will need to create a DNS record with the selector
// and matching public key.  This example does not provide
// information about DKIM DNS record creation.  
// (Chilkat does not provide an API for creating DNS records.  
// Creating the DKIM DNS record is something you would do
// manually.)

// Set the domain and selector:
// You'll need to provide your own values here..
dkim.DkimDomain := 'chilkatsoft.com';
dkim.DkimSelector := 'brisbane';

// Load a private key from any common RSA private key
// format, such as DER, PKCS8, PEM, XML, etc.
// The LoadDkimPkFile method automatically detects
// the file format and reads it appropriately.
// If a password is not required, you'll still need to provide
// a password string argument, but it is ignored.
password := 'optionalPassword';
privKey := TPrivateKey.Create(Self);
success := privKey.LoadAnyFormatFile('myPrivateKey.pem',password);
if (success <> 1) then
  begin
    Memo1.Lines.Add(privKey.LastErrorText);
    Exit;
  end;

success := dkim.SetDkimPrivateKey(privKey.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(dkim.LastErrorText);
    Exit;
  end;

// Add the DKIM-Signature header and
// returns the new MIME with DKIM-Signature added.

dkimSignedMime := dkim.AddDkimSignature(mimeData);
if (dkim.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(dkim.LastErrorText);
    Exit;
  end;

// Call SendMimeBytes to connect to the SMTP server and send.
// The connection (i.e. session) to the SMTP server remains
// open so that subsequent Send* calls may use the
// same connection.  
strFrom := 'support@chilkatsoft.com';
// To send to multiple email addresses, the strTo should be set to a comma-separated
// list of email addresses.
strTo := 'chilkat_software@yahoo.com, admin@chilkatsoft.com';
success := mailman.SendMimeBytes(strFrom,strTo,dkimSignedMime);
if (success <> 1) then
  begin
    Memo1.Lines.Add(mailman.LastErrorText);
    Exit;
  end;

// Some SMTP servers do not actually send the email until 
// the connection is closed.  In these cases, it is necessary to
// call CloseSmtpConnection for the mail to be  sent.  
// Most SMTP servers send the email immediately, and it is 
// not required to close the connection.  We'll close it here
// for the example:
success := mailman.CloseSmtpConnection();
if (success <> 1) then
  begin
    Memo1.Lines.Add('Connection to SMTP server not closed cleanly.');
  end;

Memo1.Lines.Add('DKIM Signed Mail Sent!');
end;