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Get the Number of Bytes Buffered on an SSH Channel

Demonstrates the Chilkat Ssh.GetReceivedNumBytes method, which returns how many bytes are currently available in a channel's normal receive buffer. The only argument is the channel number. It returns -1 when the channel number is invalid or its retained resources have been released.

Background: This is a non-consuming look at how much is waiting, useful for deciding whether to retrieve now or keep reading, and for reporting progress on a large transfer. It counts only the normal receive buffer — bytes in the separate stderr buffer are excluded when StderrToStdout is false. Note that data received earlier can remain available even after a disconnect, so a positive count does not imply the connection is still up.

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Local $bSuccess = False

;  Demonstrates the Ssh.GetReceivedNumBytes method, which returns the number of bytes currently
;  available in a channel's normal receive buffer.  The only argument is the channel number.
;  It returns -1 for an invalid channel or one whose resources have been released.

$oSsh = ObjCreate("Chilkat.Ssh")

Local $iSshPort = 22
$bSuccess = $oSsh.Connect("ssh.example.com",$iSshPort)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  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.
Local $sPassword = "mySshPassword"

$bSuccess = $oSsh.AuthenticatePw("mySshLogin",$sPassword)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

Local $iChannelNum = $oSsh.OpenSessionChannel()
If ($iChannelNum < 0) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

$bSuccess = $oSsh.SendReqExec($iChannelNum,"ls -l /tmp")
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  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.
$oSsh.ReadTimeoutMs = 15000

$bSuccess = $oSsh.ChannelReceiveToClose($iChannelNum)
If ($bSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

;  Find out how much is waiting before retrieving it.
Local $iNumBytes = $oSsh.GetReceivedNumBytes($iChannelNum)
If ($iNumBytes < 0) Then
    ConsoleWrite("Invalid channel, or its resources were already released." & @CRLF)
    Exit
EndIf

ConsoleWrite("Bytes available: " & $iNumBytes & @CRLF)

Local $sOutput = $oSsh.GetReceivedText($iChannelNum,"utf-8")
If ($oSsh.LastMethodSuccess = False) Then
    ConsoleWrite($oSsh.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite($sOutput & @CRLF)

$oSsh.Disconnect