(C) POP3 SSH Tunneling (Port Forwarding)

Demonstrates how to connect to a POP3 server through an SSH tunnel. Reads a POP3 mailbox and display the FROM and SUBJECT header fields of each 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;
    int numToDownload;
    int i;
    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 receiving (POP3) 
    // and sending (SMTP) email.
    mailman = CkMailMan_Create();

    // 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 = "www.my-ssh-server.com";
    sshPort = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    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 POP3 server, it is
    // for authenticating with the SSH server, which is separate.
    success = CkMailMan_SshAuthenticatePw(mailman,"ssh_login","ssh_password");
    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.

    // The SSH tunnel may be kept open for any number of 
    // POP3 connections.  

    // Set the POP3 server's hostname
    CkMailMan_putMailHost(mailman,"mail.my-pop3-server.com");

    // Set the POP3 settings for your POP3 server:
    CkMailMan_putPopUsername(mailman,"pop3_login");
    CkMailMan_putPopPassword(mailman,"pop3_password");
    CkMailMan_putMailPort(mailman,995);
    CkMailMan_putPopSsl(mailman,TRUE);

    // Connect to the POP3 server through the already-established SSH tunnel:
    success = CkMailMan_Pop3BeginSession(mailman);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        return;
    }

    // A visual inspection of the LastErrorText after
    // a successful POP3 connection will confirm the SSH tunneling.
    // Note: If the POP3 connection uses SSL/TLS, then the SSL/TLS 
    // secure channel will be wrapped within the SSH tunnel.
    printf("%s\n",CkMailMan_lastErrorText(mailman));

    // How many messages are in the POP3 inbox?
    numToDownload = CkMailMan_GetMailboxCount(mailman);
    if (numToDownload > 5) {
        numToDownload = 5;
    }

    if (numToDownload == 0) {
        CkMailMan_Dispose(mailman);
        return;
    }

    // Download a max of 5 messages

    for (i = 1; i <= numToDownload; i++) {
        email = CkMailMan_FetchByMsgnum(mailman,i);
        if (CkMailMan_getLastMethodSuccess(mailman) == FALSE) {
            printf("%s\n",CkMailMan_lastErrorText(mailman));
            CkMailMan_Dispose(mailman);
            return;
        }

        printf("%s\n",CkEmail_ck_from(email));
        printf("%s\n",CkEmail_subject(email));
        printf("----\n");
        CkEmail_Dispose(email);
    }

    // Close the connection with the POP3 server, leaving the SSH tunnel open for subsequent POP3 connections.
    success = CkMailMan_Pop3EndSession(mailman);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        return;
    }

    // Try connecting to a different POP3 server through the same aleady setup SSH tunnel:
    // Set the POP3 server's hostname
    CkMailMan_putMailHost(mailman,"mail.my-pop3-server2.com");

    // Set the POP3 settings for your POP3 server:
    CkMailMan_putPopUsername(mailman,"pop3_login2");
    CkMailMan_putPopPassword(mailman,"pop3_password2");
    CkMailMan_putMailPort(mailman,110);
    CkMailMan_putPopSsl(mailman,FALSE);

    success = CkMailMan_Pop3BeginSession(mailman);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        return;
    }

    // Review the LastErrorText to see that the connection was made via the SSH tunnel:
    printf("%s\n",CkMailMan_lastErrorText(mailman));

    success = CkMailMan_Pop3EndSession(mailman);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        return;
    }

    // Close the SSH tunnel.
    success = CkMailMan_SshCloseTunnel(mailman);
    if (success != TRUE) {
        printf("%s\n",CkMailMan_lastErrorText(mailman));
        CkMailMan_Dispose(mailman);
        return;
    }



    CkMailMan_Dispose(mailman);

    }