DataFlex

SSH Exec (Execute Command Line)

Demonstrates running a single command on an SSH server with an exec request and retrieving its output. The example connects, authenticates, opens a session channel, sends the command, reads until the server closes the channel, and then checks the exit status.

Background: exec is the workhorse of SSH automation: it runs one command and the server closes the channel when the command exits, which is a definitive end-of-output signal. No PTY is involved, so the shell runs non-interactively — no prompt, no echoed input, no ANSI escape codes — giving clean, parseable output. Remember that an accepted exec request only means the request was accepted; the command's own success is reported through the channel exit status. Command syntax depends on the remote shell, which is the user's default shell on Linux/UNIX and usually CMD.EXE on Windows SSH servers.

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Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSsh
    String sHostname
    Integer iPort
    String sPassword
    Integer iChannelNum
    String sCmdOutput
    String sTemp1
    Integer iTemp1
    Boolean bTemp1

    Move False To iSuccess

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

    //  Demonstrates running a single command on an SSH server with an exec request and retrieving
    //  its output.  An exec request runs one command and the server closes the channel when it
    //  finishes -- no PTY and no shell prompt are involved, so the output is clean and parseable.

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

    //  The hostname may be a hostname or an IP address.
    Move "ssh.example.com" To sHostname
    Move 22 To iPort
    Get ComConnect Of hoSsh sHostname iPort 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.  Several session channels may be open at once on one connection.
    Get ComOpenSessionChannel Of hoSsh To iChannelNum
    If (iChannelNum < 0) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  The command syntax depends on the remote system's shell.  On Linux/UNIX it is typically the
    //  user's default shell; on Windows SSH servers it is usually CMD.EXE.
    //    Linux/UNIX:  "ls -l /tmp"        or  "cd /etc; ls -la"
    //    Windows:     "dir"               or  "\"cd \\temp&&dir\""
    Get ComSendReqExec Of hoSsh iChannelNum "ls -l /tmp" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  IMPORTANT: Set a read timeout.  ReadTimeoutMs defaults to 0, which means no limit -- without
    //  it, this call waits forever if the server never sends channel close.
    Set ComReadTimeoutMs Of hoSsh To 15000

    //  Read the output until the server sends channel close, which happens when the command exits.
    Get ComChannelReceiveToClose Of hoSsh iChannelNum To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

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

    Showln sCmdOutput

    //  An accepted exec request does not mean the command succeeded.  Check the exit status.
    Get ComChannelReceivedExitStatus Of hoSsh iChannelNum To bTemp1
    If (bTemp1) Begin
        Get ComGetChannelExitStatus Of hoSsh iChannelNum To iTemp1
        Showln "Exit status: " iTemp1
    End

    Send ComDisconnect To hoSsh


End_Procedure