Visual Basic 6.0

Get Received SSH Bytes into a BinData

Demonstrates the Chilkat Ssh.GetReceivedBd method, which appends the bytes currently in a channel's normal receive buffer to a BinData. The first argument is the channel number and the second is the BinData. The channel receive buffer is cleared afterward; existing bytes in the BinData are preserved.

Background: When the remote command emits binary — a tarball, an image, a compressed stream — decoding it as text through a charset would corrupt it. BinData keeps the bytes exactly as received, so you can write them to a file, hash them, or hand them to another API. Like the StringBuilder form it appends, making it easy to accumulate across successive reads. On failure the BinData is left unchanged.

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Visual Basic 6.0

Dim success As Long
success = 0

'  Demonstrates the Ssh.GetReceivedBd method, which appends the bytes currently in a channel's
'  receive buffer to a BinData.  The 1st argument is the channel number and the 2nd is the
'  BinData.  The channel receive buffer is cleared afterward.

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

'  Run a command whose output may be binary.
success = ssh.SendReqExec(channelNum,"cat /usr/bin/hostname")
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

'  Append the raw received bytes to a BinData.  Existing bytes in the BinData are preserved.
Dim bd As New ChilkatBinData
success = ssh.GetReceivedBd(channelNum,bd)
If (success = 0) Then
    Debug.Print ssh.LastErrorText
    Exit Sub
End If

Debug.Print "Bytes received: " & bd.NumBytes

ssh.Disconnect