Visual Basic 6.0

Send CLOSE on an SSH Channel

Demonstrates the Chilkat Ssh.ChannelSendClose method, which sends an SSH CLOSE message for a channel and immediately marks it locally closed. The only argument is the channel number. It does not wait for remote EOF, remote CLOSE, or an exit status.

Background: CLOSE shuts down both directions of the channel, unlike EOF which closes only your side. Because the call returns without waiting for the remote side to acknowledge, it does not guarantee the remote process has terminated — so retrieve any output and exit status you care about before calling it. Afterward ChannelIsOpen reports false, though NumOpenChannels may still count the channel until final remote-close processing.

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Visual Basic 6.0

Dim success As Long
success = 0

'  Demonstrates the Ssh.ChannelSendClose method, which sends an SSH CLOSE message for a channel
'  and immediately marks it locally closed.  The only argument is the channel number.  It does
'  not wait for remote EOF, remote CLOSE, or an exit status.

Dim ssh As New ChilkatSsh

Dim sshPort As Long
sshPort = 22
success = ssh.Connect("ssh.example.com",sshPort)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
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 = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Dim channelNum As Long
channelNum = ssh.OpenSessionChannel()
If (channelNum < 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

success = ssh.SendReqExec(channelNum,"uptime")
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
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

success = ssh.ChannelReceiveToClose(channelNum)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Dim output As String
output = ssh.GetReceivedText(channelNum,"utf-8")
If (ssh.LastMethodSuccess = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Debug.Print output

'  Send CLOSE for the channel.
success = ssh.ChannelSendClose(channelNum)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

'  After a successful call, the channel is no longer reported as open.
If (ssh.ChannelIsOpen(channelNum)) Then
    Debug.Print "Still open."
Else
    Debug.Print "The channel is closed."
End If

ssh.Disconnect