PowerShell

Get Received SSH Text into a StringBuilder

Demonstrates the Chilkat Ssh.GetReceivedSb method, which decodes a channel's receive buffer and appends the text to a StringBuilder. The arguments are the channel number, the charset, and the StringBuilder. The receive buffer is cleared afterward.

Background: Because this appends rather than replaces, it is the natural choice for accumulating output across repeated reads — call it in a loop and the StringBuilder grows into the complete transcript. It also avoids creating a new string on every retrieval, which matters when a command produces a large amount of text.

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Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

#  Demonstrates the Ssh.GetReceivedSb method, which decodes the channel's receive buffer and
#  appends the text to a StringBuilder.  The 1st argument is the channel number, the 2nd is the
#  charset, and the 3rd is the StringBuilder.  The receive buffer is cleared afterward.

$ssh = New-Object Chilkat.Ssh

$sshPort = 22
$success = $ssh.Connect("ssh.example.com",$sshPort)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  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.
$password = "mySshPassword"

$success = $ssh.AuthenticatePw("mySshLogin",$password)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$channelNum = $ssh.OpenSessionChannel()
if ($channelNum -lt 0) {
    $($ssh.LastErrorText)
    exit
}

$success = $ssh.SendReqExec($channelNum,"ls -l /tmp")
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  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 -eq $false) {
    $($ssh.LastErrorText)
    exit
}

#  Append the received text to a StringBuilder.  Existing content is preserved.
$sb = New-Object Chilkat.StringBuilder
$success = $ssh.GetReceivedSb($channelNum,"utf-8",$sb)
if ($success -eq $false) {
    $($ssh.LastErrorText)
    exit
}

$("Characters received: " + $sb.Length)
$output = $sb.GetAsString()
$($output)

$ssh.Disconnect()