(Delphi DLL) Send DKIM Signed Email

Demonstrates how to send DKIM signed email.

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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, MailMan, BinData, PrivateKey, Email, Dkim;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
mailman: HCkMailMan;
dkim: HCkDkim;
email: HCkEmail;
bdMime: HCkBinData;
password: PWideChar;
privKey: HCkPrivateKey;
strRecipients: PWideChar;
strFrom: PWideChar;

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

mailman := CkMailMan_Create();
dkim := CkDkim_Create();

// SMTP server settings...
CkMailMan_putSmtpHost(mailman,'SMTP_DOMAIN');
CkMailMan_putSmtpUsername(mailman,'SMTP_LOGIN');
CkMailMan_putSmtpPassword(mailman,'SMTP_PASSWORD');
CkMailMan_putSmtpPort(mailman,465);
CkMailMan_putSmtpSsl(mailman,True);

email := CkEmail_Create();

CkEmail_putSubject(email,'This is a test');
CkEmail_putBody(email,'This is a test');
CkEmail_putFrom(email,'Chilkat Support <support@chilkatsoft.com>');

// Add some recipients (BCC recipients are added below)
CkEmail_AddTo(email,'Chilkat Software','chilkat_software@yahoo.com');
CkEmail_AddTo(email,'Chilkat Admin','admin@chilkatsoft.com');
CkEmail_AddCC(email,'Chilkat Admin','admin@chilkat.io');

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

// First get the MIME of the email.  Calling RenderToMimeBd 
// causes the email to be signed and/or encrypted if those options
// have been selected.  The MIME returned by RenderToMimeBd
// 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...
bdMime := CkBinData_Create();
success := CkMailMan_RenderToMimeBd(mailman,email,bdMime);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkMailMan__lastErrorText(mailman));
    Exit;
  end;

// To create a DKIM signature,
// 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..
CkDkim_putDkimDomain(dkim,'chilkatsoft.com');
CkDkim_putDkimSelector(dkim,'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
// an empty password string argument, but it is ignored.
password := 'passwd';
privKey := CkPrivateKey_Create();
success := CkPrivateKey_LoadAnyFormatFile(privKey,'qa_data/pem/rsa_passwd.pem',password);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey));
    Exit;
  end;

success := CkDkim_SetDkimPrivateKey(dkim,privKey);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkDkim__lastErrorText(dkim));
    Exit;
  end;

// Add the DKIM-Signature header to the MIME in bdMime
success := CkDkim_DkimSign(dkim,bdMime);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkDkim__lastErrorText(dkim));
    Exit;
  end;

// If desired, examine the MIME of the email being sent.
CkBinData_WriteFile(bdMime,'qa_output/dkimSigned.eml');

// ---- Prepare to send the email contained in bdMime ---

// To send to multiple email addresses, the strRecipients should be set to a comma-separated
// list of email addresses.

// Note: This is where we can add additional BCC addreses.
// Here we are adding "chilkat.support@gmail.com" as an additional BCC address.
// Notice that the 1st three email addresses are NOT BCC because these email addresses
// appear in the MIME header of the email (in the "To" and "CC" header fields).
// A BCC email address does not appear in the MIME, and thus the non-BCC recipients cannot see
// that the email was also sent to the BCC address.  (BCC means "blind carbon copy")
strRecipients := 'chilkat_software@yahoo.com, admin@chilkatsoft.com, admin@chilkat.io, chilkat.support@gmail.com';
strFrom := 'support@chilkatsoft.com';

success := CkMailMan_SendMimeBd(mailman,strFrom,strRecipients,bdMime);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkMailMan__lastErrorText(mailman));
    Exit;
  end;

success := CkMailMan_CloseSmtpConnection(mailman);
if (success <> True) then
  begin
    Memo1.Lines.Add('Connection to SMTP server not closed cleanly.');
  end;

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

CkMailMan_Dispose(mailman);
CkDkim_Dispose(dkim);
CkEmail_Dispose(email);
CkBinData_Dispose(bdMime);
CkPrivateKey_Dispose(privKey);

end;