(Unicode C) IMAP Use Existing SSH Tunnel

Demonstrates how to connect to an IMAP server using an existing SSH tunnel. This creates a new channel within the SSH tunnel, which can be a TCP or TLS connection, and is connected to a remote IMAP server through port forwarding.

Note: This example requires Chilkat v11.0.0 or greater.

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#include <C_CkSocketW.h>
#include <C_CkImapW.h>
#include <C_CkEmailW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSocketW tunnel;
    const wchar_t *sshHostname;
    int sshPort;
    HCkImapW imap;
    int msgCount;
    int upperBound;
    HCkEmailW email;
    int i;
    BOOL bUid;

    success = FALSE;

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

    tunnel = CkSocketW_Create();

    sshHostname = L"sftp.example.com";
    sshPort = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    success = CkSocketW_SshOpenTunnel(tunnel,sshHostname,sshPort);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(tunnel));
        CkSocketW_Dispose(tunnel);
        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 IMAP server, it is
    // for authenticating with the SSH server, which is separate.
    success = CkSocketW_SshAuthenticatePw(tunnel,L"mySshLogin",L"mySshPassword");
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(tunnel));
        CkSocketW_Dispose(tunnel);
        return;
    }

    // OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
    // Once the channel is obtained, the Socket API may
    // be used exactly the same as usual, except all communications
    // are sent through the channel in the SSH tunnel.
    // Any number of channels may be created from the same SSH tunnel.
    // Multiple channels may coexist at the same time.

    imap = CkImapW_Create();

    // Let the IMAP object also use the SSH tunnel
    success = CkImapW_UseSshTunnel(imap,tunnel);
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        return;
    }

    // Connect to an IMAP server via the already established SSH tunnel.
    // Because the SSH tunnel has been previously setup,
    // this does not establish a direct connection with the IMAP
    // server.  It directs the SSH server to establish the connection.

    // In this example, the IMAP server requires SSL/TLS.  The TLS connection
    // will be enclosed within the SSH tunnel.
    CkImapW_putSsl(imap,TRUE);
    CkImapW_putPort(imap,993);
    success = CkImapW_Connect(imap,L"imap.my-imap-server.com");
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        return;
    }

    // Authenticate with the IMAP server via the SSH tunnel.
    success = CkImapW_Login(imap,L"myLogin",L"myPassword");
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        return;
    }

    // Select an IMAP mailbox
    success = CkImapW_SelectMailbox(imap,L"Inbox");
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        return;
    }

    // How many messages in Inbox?
    msgCount = CkImapW_getNumMessages(imap);
    if (msgCount == 0) {
        wprintf(L"No messages found.\n");
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        return;
    }

    upperBound = 10;
    if (msgCount < upperBound) {
        upperBound = msgCount;
    }

    // Download up to the 1st 10 messages.
    email = CkEmailW_Create();

    bUid = FALSE;
    for (i = 1; i <= upperBound; i++) {

        success = CkImapW_FetchEmail(imap,FALSE,i,bUid,email);
        if (success == FALSE) {
            wprintf(L"%s\n",CkImapW_lastErrorText(imap));
            CkSocketW_Dispose(tunnel);
            CkImapW_Dispose(imap);
            CkEmailW_Dispose(email);
            return;
        }

        wprintf(L"%s\n",CkEmailW_ck_from(email));
        wprintf(L"%s\n",CkEmailW_subject(email));

    }

    // Disconnect from the IMAP server.
    // The SSH tunnel remains open.
    success = CkImapW_Disconnect(imap);
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        CkEmailW_Dispose(email);
        return;
    }

    // It is possible to re-use the existing SSH tunnel for the next connection:
    success = CkImapW_Connect(imap,L"imap.my-imap-server2.com");
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        CkEmailW_Dispose(email);
        return;
    }

    // Review the LastErrorText to see that the connection was made via the SSH tunnel:
    wprintf(L"%s\n",CkImapW_lastErrorText(imap));

    // This closes the SSH channel, which is the connection with the IMAP server.
    // It does not close the SSH tunnel
    success = CkImapW_Disconnect(imap);
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        CkEmailW_Dispose(email);
        return;
    }

    // Finally, close the SSH tunnel.

    // Note: If other objects are using the same SSH tunnel, the tunnel is not 
    // actually closed.  It is only closed when the last object using the tunnel closes it.

    // At this point, both the imap and tunnel objects have references to the internal
    // SSH tunnel.  We need to close each.

    // This call doesn't actually close the tunnel yet, because the tunnel object still
    // holds an internal reference.
    success = CkImapW_SshCloseTunnel(imap);
    if (success == FALSE) {
        wprintf(L"%s\n",CkImapW_lastErrorText(imap));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        CkEmailW_Dispose(email);
        return;
    }

    // This actually closes the SSH tunnel because it's the last object using it.
    success = CkSocketW_SshCloseTunnel(tunnel);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(tunnel));
        CkSocketW_Dispose(tunnel);
        CkImapW_Dispose(imap);
        CkEmailW_Dispose(email);
        return;
    }

    wprintf(L"IMAP pre-existing SSH tunnel example completed.\n");


    CkSocketW_Dispose(tunnel);
    CkImapW_Dispose(imap);
    CkEmailW_Dispose(email);

    }