B4X

Send DKIM Signed Email

See more DKIM / DomainKey Examples

Demonstrates how to send DKIM signed email. B4X

Dim success As Boolean = False

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

Dim mailman As ChilkatMailMan
mailman.Initialize("mailman")
Dim dkim As ChilkatDkim
dkim.Initialize("dkim")

'  SMTP server settings...
mailman.SmtpHost = "SMTP_DOMAIN"
mailman.SmtpUsername = "SMTP_LOGIN"
mailman.SmtpPassword = "SMTP_PASSWORD"
mailman.SmtpPort = 465
mailman.SmtpSsl = True

Dim email As ChilkatEmail
email.Initialize

email.Subject = "This is a test"
email.Body = "This is a test"
email.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...
Dim bdMime As ChilkatBinData
bdMime.Initialize
success = mailman.RenderToMimeBd(email, bdMime)
If success = False Then
    Log(mailman.LastErrorText)
    Return
End If


'  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.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
'  an empty password string argument, but it is ignored.
Dim password As String = "passwd"
Dim privKey As ChilkatPrivateKey
privKey.Initialize("privKey")
success = privKey.LoadAnyFormatFile("qa_data/pem/rsa_passwd.pem", password)
If success = False Then
    Log(privKey.LastErrorText)
    Return
End If


success = dkim.SetDkimPrivateKey(privKey)
If success = False Then
    Log(dkim.LastErrorText)
    Return
End If


'  Add the DKIM-Signature header to the MIME in bdMime
success = dkim.DkimSign(bdMime)
If success = False Then
    Log(dkim.LastErrorText)
    Return
End If


'  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")
Dim strRecipients As String = "chilkat_software@yahoo.com, admin@chilkatsoft.com, admin@chilkat.io, chilkat.support@gmail.com"
Dim strFrom As String = "support@chilkatsoft.com"

success = mailman.SendMimeBd(strFrom, strRecipients, bdMime)
If success = False Then
    Log(mailman.LastErrorText)
    Return
End If


success = mailman.CloseSmtpConnection
If success <> True Then
    Log("Connection to SMTP server not closed cleanly.")
End If


Log("DKIM Signed Mail Sent!")