(PHP ActiveX) Send DKIM Signed Email

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

// 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.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.MailMan')
$mailman = new COM("Chilkat.MailMan");

// The dkim object is used for creating the DKIM signature.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Dkim')
$dkim = new COM("Chilkat.Dkim");

// 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
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Email')
$email = new COM("Chilkat.Email");

$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);
if ($mailman->LastMethodSuccess != 1) {
    print $mailman->LastErrorText . "\n";
    exit;
}

// 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';
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.PrivateKey')
$privKey = new COM("Chilkat.PrivateKey");
$success = $privKey->LoadAnyFormatFile('myPrivateKey.pem',$password);
if ($success != 1) {
    print $privKey->LastErrorText . "\n";
    exit;
}

$success = $dkim->SetDkimPrivateKey($privKey);
if ($success != 1) {
    print $dkim->LastErrorText . "\n";
    exit;
}

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

$dkimSignedMime = $dkim->AddDkimSignature($mimeData);
if ($dkim->LastMethodSuccess != 1) {
    print $dkim->LastErrorText . "\n";
    exit;
}

// 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) {
    print $mailman->LastErrorText . "\n";
    exit;
}

// 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) {
    print 'Connection to SMTP server not closed cleanly.' . "\n";
}

print 'DKIM Signed Mail Sent!' . "\n";

?>