Xojo Plugin

Receive an SSH Channel Until Close

Demonstrates the Chilkat Ssh.ChannelReceiveToClose method, which receives data on a channel until the server sends and Chilkat processes channel CLOSE. The only argument is the channel number. EOF alone does not complete this method.

Important: Set the ReadTimeoutMs property before calling this method. It defaults to 0, meaning no limit, so without it the call waits forever if the server never sends channel close.

Background: This is the simplest and most reliable way to collect the complete output of a one-shot exec command, because the server closes the channel when the command finishes. It is not appropriate for an interactive shell, which never closes on its own — use the poll-based methods there instead. Both stdout and stderr are processed, merged or kept separate according to StderrToStdout.

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Dim success As Boolean
success = False

//  Demonstrates the Ssh.ChannelReceiveToClose method, which receives data on a channel until the
//  server sends channel CLOSE.  The only argument is the channel number.  EOF alone does not
//  complete this method.

Dim ssh As New Chilkat.Ssh

Dim sshPort As Int32
sshPort = 22
success = ssh.Connect("ssh.example.com",sshPort)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

//  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.
Dim password As String
password = "mySshPassword"

success = ssh.AuthenticatePw("mySshLogin",password)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

Dim channelNum As Int32
channelNum = ssh.OpenSessionChannel()
If (channelNum < 0) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

success = ssh.SendReqExec(channelNum,"ls -l /tmp")
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

//  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.
ssh.ReadTimeoutMs = 15000

//  Receive everything the command produces, up to and including channel close.
success = ssh.ChannelReceiveToClose(channelNum)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

Dim output As String
output = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

System.DebugLog(output)

ssh.Disconnect