C
C
Send DKIM Signed Email
See more DKIM / DomainKey Examples
Demonstrates how to send DKIM signed email.Chilkat C Downloads
#include <C_CkMailMan.h>
#include <C_CkDkim.h>
#include <C_CkEmail.h>
#include <C_CkBinData.h>
#include <C_CkPrivateKey.h>
void ChilkatSample(void)
{
BOOL success;
HCkMailMan mailman;
HCkDkim dkim;
HCkEmail email;
HCkBinData bdMime;
const char *password;
HCkPrivateKey privKey;
const char *strRecipients;
const char *strFrom;
success = FALSE;
// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.
mailman = CkMailMan_Create();
dkim = CkDkim_Create();
// SMTP server settings...
CkMailMan_putSmtpHost(mailman,"SMTP_DOMAIN");
CkMailMan_putSmtpUsername(mailman,"SMTP_LOGIN");
CkMailMan_putSmtpPassword(mailman,"SMTP_PASSWORD");
CkMailMan_putSmtpPort(mailman,465);
CkMailMan_putSmtpSsl(mailman,TRUE);
email = CkEmail_Create();
CkEmail_putSubject(email,"This is a test");
CkEmail_putBody(email,"This is a test");
CkEmail_putFrom(email,"Chilkat Support <support@chilkatsoft.com>");
// Add some recipients (BCC recipients are added below)
CkEmail_AddTo(email,"Chilkat Software","chilkat_software@yahoo.com");
CkEmail_AddTo(email,"Chilkat Admin","admin@chilkatsoft.com");
CkEmail_AddCC(email,"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 = CkBinData_Create();
success = CkMailMan_RenderToMimeBd(mailman,email,bdMime);
if (success == FALSE) {
printf("%s\n",CkMailMan_lastErrorText(mailman));
CkMailMan_Dispose(mailman);
CkDkim_Dispose(dkim);
CkEmail_Dispose(email);
CkBinData_Dispose(bdMime);
return;
}
// 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..
CkDkim_putDkimDomain(dkim,"chilkatsoft.com");
CkDkim_putDkimSelector(dkim,"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 = CkPrivateKey_Create();
success = CkPrivateKey_LoadAnyFormatFile(privKey,"qa_data/pem/rsa_passwd.pem",password);
if (success == FALSE) {
printf("%s\n",CkPrivateKey_lastErrorText(privKey));
CkMailMan_Dispose(mailman);
CkDkim_Dispose(dkim);
CkEmail_Dispose(email);
CkBinData_Dispose(bdMime);
CkPrivateKey_Dispose(privKey);
return;
}
success = CkDkim_SetDkimPrivateKey(dkim,privKey);
if (success == FALSE) {
printf("%s\n",CkDkim_lastErrorText(dkim));
CkMailMan_Dispose(mailman);
CkDkim_Dispose(dkim);
CkEmail_Dispose(email);
CkBinData_Dispose(bdMime);
CkPrivateKey_Dispose(privKey);
return;
}
// Add the DKIM-Signature header to the MIME in bdMime
success = CkDkim_DkimSign(dkim,bdMime);
if (success == FALSE) {
printf("%s\n",CkDkim_lastErrorText(dkim));
CkMailMan_Dispose(mailman);
CkDkim_Dispose(dkim);
CkEmail_Dispose(email);
CkBinData_Dispose(bdMime);
CkPrivateKey_Dispose(privKey);
return;
}
// If desired, examine the MIME of the email being sent.
CkBinData_WriteFile(bdMime,"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 = CkMailMan_SendMimeBd(mailman,strFrom,strRecipients,bdMime);
if (success == FALSE) {
printf("%s\n",CkMailMan_lastErrorText(mailman));
CkMailMan_Dispose(mailman);
CkDkim_Dispose(dkim);
CkEmail_Dispose(email);
CkBinData_Dispose(bdMime);
CkPrivateKey_Dispose(privKey);
return;
}
success = CkMailMan_CloseSmtpConnection(mailman);
if (success != TRUE) {
printf("Connection to SMTP server not closed cleanly.\n");
}
printf("DKIM Signed Mail Sent!\n");
CkMailMan_Dispose(mailman);
CkDkim_Dispose(dkim);
CkEmail_Dispose(email);
CkBinData_Dispose(bdMime);
CkPrivateKey_Dispose(privKey);
}