DataFlex

Abort a Running SSH Tunnel Operation

Demonstrates the AbortCurrent property, which requests that the currently running foreground operation be aborted. It is intended to be set to true from another thread — for example, to interrupt a synchronous Connect that is waiting for an unresponsive server.

Background: A synchronous call like Connect blocks the calling thread until it finishes or times out, which is a problem when a user clicks "Cancel" or the app needs to shut down. Setting AbortCurrent from a different thread breaks the blocked operation out early, returning a failure the caller can handle. Note its scope is deliberately limited to the current foreground operation: it does not stop the background listener or terminate established tunnel clients — use StopAccepting or CloseTunnel for those.

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DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoTunnel
    Integer iSshPort
    Boolean iWaitForThreadExit
    String sTemp1

    Move False To iSuccess

    //  Demonstrates the SshTunnel.AbortCurrent property, which requests that the currently running
    //  foreground operation be aborted.

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

    //  AbortCurrent is intended to be set to True from ANOTHER thread to interrupt a synchronous
    //  operation in progress -- for example, a Connect that is waiting for an unresponsive server.
    //  It does not stop the background listener or terminate established background tunnel clients.
    //  
    //  The assignment below illustrates the property.  In a real application it would be set on a
    //  separate thread while Connect blocks; if it becomes True, the blocked Connect returns with a
    //  failure.
    Set ComAbortCurrent Of hoTunnel To False

    Set ComDestHostname Of hoTunnel To "db.internal.example.com"
    Set ComDestPort Of hoTunnel To 5432

    Move 22 To iSshPort
    Get ComConnect Of hoTunnel "ssh.example.com" iSshPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Connected."

    Move True To iWaitForThreadExit
    Get ComCloseTunnel Of hoTunnel iWaitForThreadExit To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoTunnel To sTemp1
        Showln sTemp1
        Procedure_Return
    End



End_Procedure