(C) SMTP SSH Tunneling (Port Forwarding)

Demonstrates how to setup an SSH tunnel for SMTP. This example connects to an SMTP sever via an SSH tunnel and sends an email.

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#include <C_CkMailMan.h>
#include <C_CkEmail.h>

void ChilkatSample(void)
    {
    HCkMailMan mailman;
    const char *sshHostname;
    int sshPort;
    BOOL success;
    HCkEmail email;

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

    // The mailman object is used for sending (SMTP) and receiving (POP3) email.
    mailman = CkMailMan_Create();

    // Connect to an SSH server and establish the SSH tunnel:

    // The SSH hostname may be a hostname or an 
    // IP address, such as "192.168.1.108".
    // The port is typically 22 (the standard port for SSH).
    sshHostname = "sftp.example.com";
    sshPort = 22;

    success = CkMailMan_SshOpenTunnel(mailman,sshHostname,sshPort);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        return;
    }

    // Authenticate with the SSH server via a login/password
    // or with a public key.
    // This example demonstrates SSH password authentication.
    // Note: This is not authenticating with the SMTP server, it is
    // for authenticating with the SSH server, which is separate.
    success = CkMailMan_SshAuthenticatePw(mailman,"sshLogin","sshPassword");
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        return;
    }

    // OK, the SSH tunnel is setup.  The mailman may
    // be used exactly the same as usual, except all communications
    // are now sent through the SSH tunnel.

    // Set the SMTP server.
    CkMailMan_putSmtpHost(mailman,"smtp.my-smtp-server.com");

    // Set the SMTP login/password (if required)
    CkMailMan_putSmtpUsername(mailman,"smtpLogin");
    CkMailMan_putSmtpPassword(mailman,"smtpPassword");

    // Create a new email object
    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>");
    success = CkEmail_AddTo(email,"Chilkat Admin","admin@chilkatsoft.com");

    // The call to SendEmail automatically connects to the SMTP
    // server via the SSH tunnel (if not already connected).
    // Because the SSH tunnel has been previously setup,
    // this does not establish a direct connection with the SMTP
    // server.  It directs the SSH server to establish the connection.

    // After SendEmail completes, the connection (i.e. session) remains
    // open so that subsequent SendEmail calls may use the
    // same SSH tunnel.  
    success = CkMailMan_SendEmail(mailman,email);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        CkEmail_Dispose(email);
        return;
    }

    // If you're curious, have a look at LastErrorText after
    // a successful send.  You'll see detailed information that 
    // confirms the SSH tunneling.
    printf("%s\n",CkMailMan_lastErrorText(mailman));

    // Note: Some SMTP servers do not actually send the email until 
    // the connection is closed.  In these cases, it is necessary to
    // call CloseSmtpConnection for the mail to be  sent.  
    // Most SMTP servers send the email immediately, and it is 
    // not required to close the connection.  

    printf("Mail Sent!\n");


    CkMailMan_Dispose(mailman);
    CkEmail_Dispose(email);

    }