DataFlex

Send Text on an SSH Channel

Demonstrates the Chilkat Ssh.ChannelSendString method, which encodes text using a charset and sends the resulting bytes on a channel. The arguments are the channel number, the text, and the charset. No line ending or terminator is added automatically.

Background: This is how you type into a remote shell programmatically. The most common mistake is forgetting the newline — the remote shell will not act on a command until it receives one, so the terminator must be part of the text you send. An empty string is valid and sends zero bytes. The charset governs how the text becomes bytes on the wire.

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DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSsh
    Integer iSshPort
    String sPassword
    Integer iChannelNum
    Integer iPollTimeoutMs
    Integer iResult
    String sOutput
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

    //  Demonstrates the Ssh.ChannelSendString method, which encodes text with a charset and sends
    //  the bytes on a channel.  The 1st argument is the channel number, the 2nd is the text, and the
    //  3rd is the charset.  No line ending is added automatically.

    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

    Get ComOpenSessionChannel Of hoSsh To iChannelNum
    If (iChannelNum < 0) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Start a shell WITHOUT requesting a PTY.  Without a PTY the shell sees it is connected to a
    //  raw data pipe and enters non-interactive mode: it suppresses the command prompt, does not
    //  echo typed commands back, and skips interactive login scripts.  The output is therefore
    //  clean and easily parseable -- but because no prompt is ever sent, code must not wait for
    //  one.  Instead, have each command print a predictable marker, or wait for EOF / channel close.
    Get ComSendReqShell Of hoSsh iChannelNum To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Send a command.  The trailing newline must be included because no terminator is added.
    Get ComChannelSendString Of hoSsh iChannelNum "ls -l /tmp" + (character(10)) "utf-8" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Read the shell's response.
    Move 2000 To iPollTimeoutMs
    Get ComChannelReadAndPoll Of hoSsh iChannelNum iPollTimeoutMs To iResult
    If (iResult = -1) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComGetReceivedText Of hoSsh iChannelNum "utf-8" To sOutput
    Get ComLastMethodSuccess Of hoSsh To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln sOutput

    Send ComDisconnect To hoSsh


End_Procedure