DataFlex

Request a Pseudo-Terminal (PTY) over SSH

Demonstrates the Chilkat Ssh.SendReqPty method, which requests a pseudo-terminal for a session channel. The arguments are the channel number, the terminal type, the character width and height, and the pixel width and height. It must be sent before the primary exec or shell request.

Background: A PTY makes the remote side behave as though a real terminal is attached, which matters for programs that draw screens, prompt for passwords, or colorize output — many refuse to run interactively without one. The terminal type (such as xterm) tells the remote program what escape sequences it may use. Pixel dimensions are commonly 0, meaning unspecified.

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DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSsh
    Integer iSshPort
    String sPassword
    Integer iChannelNum
    String sTermType
    Integer iWidthInChars
    Integer iHeightInChars
    Integer iWidthInPixels
    Integer iHeightInPixels
    String sTemp1

    Move False To iSuccess

    //  Demonstrates the Ssh.SendReqPty method, which requests a pseudo-terminal for a session
    //  channel.  The 1st argument is the channel number, the 2nd is the terminal type, the 3rd and
    //  4th are the character width and height, and the 5th and 6th are the pixel width and height.
    //  It must be sent before the primary exec or shell request.

    Get Create (RefClass(cComChilkatSsh)) To hoSsh
    If (Not(IsComObjectCreated(hoSsh))) Begin
        Send CreateComObject of hoSsh
    End

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

    //  Normally you would not hard-code the password in source.  You should instead obtain it
    //  from an interactive prompt, environment variable, or a secrets vault.
    Move "mySshPassword" To sPassword

    Get ComAuthenticatePw Of hoSsh "mySshLogin" sPassword To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Open a session channel.  A negative return value indicates failure.
    Get ComOpenSessionChannel Of hoSsh To iChannelNum
    If (iChannelNum < 0) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Request an 80x24 xterm.  Pixel dimensions of 0 mean unspecified.
    Move "xterm" To sTermType
    Move 80 To iWidthInChars
    Move 24 To iHeightInChars
    Move 0 To iWidthInPixels
    Move 0 To iHeightInPixels
    Get ComSendReqPty Of hoSsh iChannelNum sTermType iWidthInChars iHeightInChars iWidthInPixels iHeightInPixels To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Start the shell now that the PTY is allocated.
    Get ComSendReqShell Of hoSsh iChannelNum To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Send ComDisconnect To hoSsh


End_Procedure