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. C++

#include <CkSocket.h>
#include <CkImap.h>
#include <CkEmail.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    CkSocket tunnel;

    const char *sshHostname = "sftp.example.com";
    int sshPort = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    success = tunnel.SshOpenTunnel(sshHostname,sshPort);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        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 = tunnel.SshAuthenticatePw("mySshLogin","mySshPassword");
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        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.

    CkImap imap;

    // Let the IMAP object also use the SSH tunnel
    success = imap.UseSshTunnel(tunnel);
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        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.
    imap.put_Ssl(true);
    imap.put_Port(993);
    success = imap.Connect("imap.my-imap-server.com");
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // Authenticate with the IMAP server via the SSH tunnel.
    success = imap.Login("myLogin","myPassword");
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // Select an IMAP mailbox
    success = imap.SelectMailbox("Inbox");
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // How many messages in Inbox?
    int msgCount = imap.get_NumMessages();
    if (msgCount == 0) {
        std::cout << "No messages found." << "\r\n";
        return;
    }

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

    // Download up to the 1st 10 messages.
    CkEmail email;
    int i;
    bool bUid = false;
    for (i = 1; i <= upperBound; i++) {

        success = imap.FetchEmail(false,i,bUid,email);
        if (success == false) {
            std::cout << imap.lastErrorText() << "\r\n";
            return;
        }

        std::cout << email.ck_from() << "\r\n";
        std::cout << email.subject() << "\r\n";

    }

    // Disconnect from the IMAP server.
    // The SSH tunnel remains open.
    success = imap.Disconnect();
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // It is possible to re-use the existing SSH tunnel for the next connection:
    success = imap.Connect("imap.my-imap-server2.com");
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // Review the LastErrorText to see that the connection was made via the SSH tunnel:
    std::cout << imap.lastErrorText() << "\r\n";

    // This closes the SSH channel, which is the connection with the IMAP server.
    // It does not close the SSH tunnel
    success = imap.Disconnect();
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        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 = imap.SshCloseTunnel();
    if (success == false) {
        std::cout << imap.lastErrorText() << "\r\n";
        return;
    }

    // This actually closes the SSH tunnel because it's the last object using it.
    success = tunnel.SshCloseTunnel();
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "IMAP pre-existing SSH tunnel example completed." << "\r\n";
    }