(PHP Extension) Send DKIM Signed Email

Demonstrates how to send DKIM signed email.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

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

$mailman = new CkMailMan();
$dkim = new CkDkim();

// SMTP server settings...
$mailman->put_SmtpHost('SMTP_DOMAIN');
$mailman->put_SmtpUsername('SMTP_LOGIN');
$mailman->put_SmtpPassword('SMTP_PASSWORD');
$mailman->put_SmtpPort(465);
$mailman->put_SmtpSsl(true);

$email = new CkEmail();

$email->put_Subject('This is a test');
$email->put_Body('This is a test');
$email->put_From('Chilkat Support <support@chilkatsoft.com>');

// Add some recipients (BCC recipients are added below)
$email->AddTo('Chilkat Software','chilkat_software@yahoo.com');
$email->AddTo('Chilkat Admin','admin@chilkatsoft.com');
$email->AddCC('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 = new CkBinData();
$success = $mailman->RenderToMimeBd($email,$bdMime);
if ($success != true) {
    print $mailman->lastErrorText() . "\n";
    exit;
}

// 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..
$dkim->put_DkimDomain('chilkatsoft.com');
$dkim->put_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
// an empty password string argument, but it is ignored.
$password = 'passwd';
$privKey = new CkPrivateKey();
$success = $privKey->LoadAnyFormatFile('qa_data/pem/rsa_passwd.pem',$password);
if ($success != true) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

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

// Add the DKIM-Signature header to the MIME in bdMime
$success = $dkim->DkimSign($bdMime);
if ($success != true) {
    print $dkim->lastErrorText() . "\n";
    exit;
}

// If desired, examine the MIME of the email being sent.
$bdMime->WriteFile('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 = $mailman->SendMimeBd($strFrom,$strRecipients,$bdMime);
if ($success != true) {
    print $mailman->lastErrorText() . "\n";
    exit;
}

$success = $mailman->CloseSmtpConnection();
if ($success != true) {
    print 'Connection to SMTP server not closed cleanly.' . "\n";
}

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

?>