SSH Remote Shell

Demonstrates how to start a shell on a remote SSH server, run a command, and retrieve the output.

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'  Important: It is helpful to send the contents of the
'  ssh.LastErrorText property when requesting support.

Dim ssh As New Chilkat.Ssh()

'  Any string automatically begins a fully-functional 30-day trial.
Dim success As Boolean
success = ssh.UnlockComponent("30-day trial")
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Connect to an SSH server:
Dim hostname As String
Dim port As Long

'  Hostname may be an IP address or hostname:
hostname = "www.some-ssh-server.com"
port = 22

success = ssh.Connect(hostname,port)
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Wait a max of 5 seconds when reading responses..
ssh.IdleTimeoutMs = 5000

'  Authenticate using login/password:
success = ssh.AuthenticatePw("myLogin","myPassword")
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Open a session channel.  (It is possible to have multiple
'  session channels open simultaneously.)
Dim channelNum As Long
channelNum = ssh.OpenSessionChannel()
If (channelNum < 0) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Some SSH servers require a pseudo-terminal
'  If so, include the call to SendReqPty.  If not, then
'  comment out the call to SendReqPty.
'  Note: The 2nd argument of SendReqPty is the terminal type,
'  which should be something like "xterm", "vt100", "dumb", etc.
'  A "dumb" terminal is one that cannot process escape sequences.
'  Smart terminals, such as "xterm", "vt100", etc. process
'  escape sequences.  If you select a type of smart terminal,
'  your application will receive these escape sequences
'  included in the command's output.  Use "dumb" if you do not
'  want to receive escape sequences.  (Assuming your SSH
'  server recognizes "dumb" as a standard dumb terminal.)
Dim termType As String
termType = "dumb"
Dim widthInChars As Long
widthInChars = 120
Dim heightInChars As Long
heightInChars = 40
'  Use 0 for pixWidth and pixHeight when the dimensions
'  are set in number-of-chars.
Dim pixWidth As Long
pixWidth = 0
Dim pixHeight As Long
pixHeight = 0
success = ssh.SendReqPty(channelNum,termType,widthInChars,heightInChars,pixWidth,pixHeight)
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Start a shell on the channel:
success = ssh.SendReqShell(channelNum)
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Start a command in the remote shell.  This example
'  will send a "dir" command to retrieve the directory listing.
success = ssh.ChannelSendString(channelNum,"dir" & vbCrLf,"ansi")
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Send an EOF.  This tells the server that no more data will
'  be sent on this channel.  The channel remains open, and
'  the SSH client may still receive output on this channel.
success = ssh.ChannelSendEof(channelNum)
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Read whatever output may already be available on the
'  SSH connection.  ChannelReadAndPoll returns the number of bytes
'  that are available in the channel's internal buffer that
'  are ready to be "picked up" by calling GetReceivedText
'  or GetReceivedData.
'  A return value of -1 indicates failure.
'  A return value of -2 indicates a failure via timeout.

'  The ChannelReadAndPoll method waits
'  for data to arrive on the connection usingi the IdleTimeoutMs
'  property setting.  Once the first data arrives, it continues
'  reading but instead uses the pollTimeoutMs passed in the 2nd argument:
'  A return value of -2 indicates a timeout where no data is received.
Dim n As Long
Dim pollTimeoutMs As Long
pollTimeoutMs = 2000
n = ssh.ChannelReadAndPoll(channelNum,pollTimeoutMs)
If (n < 0) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Close the channel:
success = ssh.ChannelSendClose(channelNum)
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Perhaps we did not receive all of the commands output.
'  To make sure,  call ChannelReceiveToClose to accumulate any remaining
'  output until the server's corresponding "channel close" is received.
success = ssh.ChannelReceiveToClose(channelNum)
If (success <> true) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Let's pickup the accumulated output of the command:
Dim cmdOutput As String
cmdOutput = ssh.GetReceivedText(channelNum,"ansi")
If (cmdOutput = vbNullString ) Then
    MsgBox(ssh.LastErrorText)
    Exit Sub
End If


'  Display the remote shell's command output:
TextBox1.Text = TextBox1.Text & cmdOutput & vbCrLf

'  Disconnect
ssh.Disconnect()