(Xojo Plugin) Multiple SendReqExec on Same Connection

Shows how to execute a series of commands on an SSH server and retrieve each command's output (using SendReqExec). Each call to SendReqExec requires its own logical channel. This is not a separate SSH connection -- it's simply a new session channel on the existing SSH connection.

Chilkat Xojo Plugin Download Xojo Plugin for Windows, Linux, Mac OS X, and ARM, ARM64

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Dim ssh As New Chilkat.Ssh

// Hostname may be an IP address or domain:
Dim hostname As String
hostname = "172.16.16.46"
Dim port As Int32
port = 22

Dim success As Boolean
success = ssh.Connect(hostname,port)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

// If receiving output from a command stalls for more than 5 seconds, then stop waiting.
ssh.IdleTimeoutMs = 5000

// Authenticate using login/password:
success = ssh.AuthenticatePw("myLogin","myPassword")
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

// Open a session channel.  (It is possible to have multiple
// session channels open simultaneously.)
Dim channelNum As Int32
channelNum = ssh.OpenSessionChannel()
If (channelNum < 0) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

// Request a directory listing on the remote server:
// If your server is Linux/UNIX, change the string from "dir" to "ls"
// Note: Some SSH servers require a CRLF instead of a bare-LF
Dim cmd As String
cmd = "ls -al" + EndOfLine.Unix
success = ssh.SendReqExec(channelNum,cmd)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
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 pollTimeoutMs As Int32
pollTimeoutMs = 2000
Dim n As Int32
n = ssh.ChannelReadAndPoll(channelNum,pollTimeoutMs)
If (n < 0) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

// Close the channel:
success = ssh.ChannelSendClose(channelNum)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
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 = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

// Get the accumulated output of the command:
Dim cmdOutput As String
cmdOutput = ssh.GetReceivedText(channelNum,"ansi")
If (ssh.LastMethodSuccess = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

// Display the remote shell's command output:
System.DebugLog(cmdOutput)
System.DebugLog("----")

// -----------------------------------------------------------------
// Now for the 2nd SendReqExe (on the same connection,
// but on a separate logical channel).
// -----------------------------------------------------------------

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

cmd = "nslookup chilkatsoft.com" + EndOfLine.Unix
success = ssh.SendReqExec(channelNum,cmd)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

pollTimeoutMs = 2000
n = ssh.ChannelReadAndPoll(channelNum,pollTimeoutMs)
If (n < 0) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

success = ssh.ChannelSendClose(channelNum)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

success = ssh.ChannelReceiveToClose(channelNum)
If (success = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

cmdOutput = ssh.GetReceivedText(channelNum,"ansi")
If (ssh.LastMethodSuccess = False) Then
    System.DebugLog(ssh.LastErrorText)
    Return
End If

System.DebugLog(cmdOutput)