DataFlex

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. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Variant vTunnel
    Handle hoTunnel
    String sSshHostname
    Integer iSshPort
    Handle hoImap
    Integer iMsgCount
    Integer iUpperBound
    Variant vEmail
    Handle hoEmail
    Integer i
    Boolean iBUid
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatSocket)) To hoTunnel
    If (Not(IsComObjectCreated(hoTunnel))) Begin
        Send CreateComObject of hoTunnel
    End

    Move "sftp.example.com" To sSshHostname
    Move 22 To iSshPort

    // Connect to an SSH server and establish the SSH tunnel:
    Get ComSshOpenTunnel Of hoTunnel sSshHostname iSshPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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.
    Get ComSshAuthenticatePw Of hoTunnel "mySshLogin" "mySshPassword" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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.

    Get Create (RefClass(cComChilkatImap)) To hoImap
    If (Not(IsComObjectCreated(hoImap))) Begin
        Send CreateComObject of hoImap
    End

    // Let the IMAP object also use the SSH tunnel
    Get pvComObject of hoTunnel to vTunnel
    Get ComUseSshTunnel Of hoImap vTunnel To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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.
    Set ComSsl Of hoImap To True
    Set ComPort Of hoImap To 993
    Get ComConnect Of hoImap "imap.my-imap-server.com" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Authenticate with the IMAP server via the SSH tunnel.
    Get ComLogin Of hoImap "myLogin" "myPassword" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Select an IMAP mailbox
    Get ComSelectMailbox Of hoImap "Inbox" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // How many messages in Inbox?
    Get ComNumMessages Of hoImap To iMsgCount
    If (iMsgCount = 0) Begin
        Showln "No messages found."
        Procedure_Return
    End

    Move 10 To iUpperBound
    If (iMsgCount < iUpperBound) Begin
        Move iMsgCount To iUpperBound
    End

    // Download up to the 1st 10 messages.
    Get Create (RefClass(cComChilkatEmail)) To hoEmail
    If (Not(IsComObjectCreated(hoEmail))) Begin
        Send CreateComObject of hoEmail
    End

    Move False To iBUid
    For i From 1 To iUpperBound

        Get pvComObject of hoEmail to vEmail
        Get ComFetchEmail Of hoImap False i iBUid vEmail To iSuccess
        If (iSuccess = False) Begin
            Get ComLastErrorText Of hoImap To sTemp1
            Showln sTemp1
            Procedure_Return
        End

        Get ComFrom Of hoEmail To sTemp1
        Showln sTemp1
        Get ComSubject Of hoEmail To sTemp1
        Showln sTemp1

    Loop

    // Disconnect from the IMAP server.
    // The SSH tunnel remains open.
    Get ComDisconnect Of hoImap To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // It is possible to re-use the existing SSH tunnel for the next connection:
    Get ComConnect Of hoImap "imap.my-imap-server2.com" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Review the LastErrorText to see that the connection was made via the SSH tunnel:
    Get ComLastErrorText Of hoImap To sTemp1
    Showln sTemp1

    // This closes the SSH channel, which is the connection with the IMAP server.
    // It does not close the SSH tunnel
    Get ComDisconnect Of hoImap To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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.
    Get ComSshCloseTunnel Of hoImap To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoImap To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // This actually closes the SSH tunnel because it's the last object using it.
    Get ComSshCloseTunnel Of hoTunnel To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "IMAP pre-existing SSH tunnel example completed."


End_Procedure