(Lianja) Send DKIM Signed Email

Demonstrates how to send DKIM signed email.

Chilkat Lianja Extension Download Chilkat Lianja Extension

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

loMailman = createobject("CkMailMan")
loDkim = createobject("CkDkim")

// SMTP server settings...
loMailman.SmtpHost = "SMTP_DOMAIN"
loMailman.SmtpUsername = "SMTP_LOGIN"
loMailman.SmtpPassword = "SMTP_PASSWORD"
loMailman.SmtpPort = 465
loMailman.SmtpSsl = .T.

loEmail = createobject("CkEmail")

loEmail.Subject = "This is a test"
loEmail.Body = "This is a test"
loEmail.From = "Chilkat Support <support@chilkatsoft.com>"

// Add some recipients (BCC recipients are added below)
loEmail.AddTo("Chilkat Software","chilkat_software@yahoo.com")
loEmail.AddTo("Chilkat Admin","admin@chilkatsoft.com")
loEmail.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...
loBdMime = createobject("CkBinData")
llSuccess = loMailman.RenderToMimeBd(loEmail,loBdMime)
if (llSuccess <> .T.) then
    ? loMailman.LastErrorText
    release loMailman
    release loDkim
    release loEmail
    release loBdMime
    return
endif

// 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..
loDkim.DkimDomain = "chilkatsoft.com"
loDkim.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.
lcPassword = "passwd"
loPrivKey = createobject("CkPrivateKey")
llSuccess = loPrivKey.LoadAnyFormatFile("qa_data/pem/rsa_passwd.pem",lcPassword)
if (llSuccess <> .T.) then
    ? loPrivKey.LastErrorText
    release loMailman
    release loDkim
    release loEmail
    release loBdMime
    release loPrivKey
    return
endif

llSuccess = loDkim.SetDkimPrivateKey(loPrivKey)
if (llSuccess <> .T.) then
    ? loDkim.LastErrorText
    release loMailman
    release loDkim
    release loEmail
    release loBdMime
    release loPrivKey
    return
endif

// Add the DKIM-Signature header to the MIME in bdMime
llSuccess = loDkim.DkimSign(loBdMime)
if (llSuccess <> .T.) then
    ? loDkim.LastErrorText
    release loMailman
    release loDkim
    release loEmail
    release loBdMime
    release loPrivKey
    return
endif

// If desired, examine the MIME of the email being sent.
loBdMime.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")
lcStrRecipients = "chilkat_software@yahoo.com, admin@chilkatsoft.com, admin@chilkat.io, chilkat.support@gmail.com"
lcStrFrom = "support@chilkatsoft.com"

llSuccess = loMailman.SendMimeBd(lcStrFrom,lcStrRecipients,loBdMime)
if (llSuccess <> .T.) then
    ? loMailman.LastErrorText
    release loMailman
    release loDkim
    release loEmail
    release loBdMime
    release loPrivKey
    return
endif

llSuccess = loMailman.CloseSmtpConnection()
if (llSuccess <> .T.) then
    ? "Connection to SMTP server not closed cleanly."
endif

? "DKIM Signed Mail Sent!"


release loMailman
release loDkim
release loEmail
release loBdMime
release loPrivKey