(Perl) Send DKIM Signed Email

Demonstrates how to send DKIM signed email.

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

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

$mailman = chilkat::CkMailMan->new();
$dkim = chilkat::CkDkim->new();

# 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(1);

$email = chilkat::CkEmail->new();

$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 = chilkat::CkBinData->new();
$success = $mailman->RenderToMimeBd($email,$bdMime);
if ($success != 1) {
    print $mailman->lastErrorText() . "\r\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 = chilkat::CkPrivateKey->new();
$success = $privKey->LoadAnyFormatFile("qa_data/pem/rsa_passwd.pem",$password);
if ($success != 1) {
    print $privKey->lastErrorText() . "\r\n";
    exit;
}

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

# Add the DKIM-Signature header to the MIME in bdMime
$success = $dkim->DkimSign($bdMime);
if ($success != 1) {
    print $dkim->lastErrorText() . "\r\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 != 1) {
    print $mailman->lastErrorText() . "\r\n";
    exit;
}

$success = $mailman->CloseSmtpConnection();
if ($success != 1) {
    print "Connection to SMTP server not closed cleanly." . "\r\n";
}

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