Read in output stream through ssh connection using Renci.SshNet - wpf

Question

I've looked at a lot of other stack overflow posts but none of them really were similar to what I am trying to accomplish. Basically, I am trying to connect to a device running Windows CE through an SSH connection and capture any output that is printed to the terminal. When I connect via ssh using Putty I can see many print statements in the terminal which are used for debugging. I am trying to capture these debugging statements and use them in my wpf application. These debugging statements are not a response to a command, they are just printed to the terminal.
So far I am able to send a command and receive a single response but what I am looking for is to be able to receive a response indefinitely, until the user closes the connection or the application.
I am using Renci.SshNet to send my commands and I was messing around with using a ShellStream but was not able to get it working. Here is what I have so far:
using System;
using System.Threading;
using System.Windows;
using Renci.SshNet;
namespace TestSshConsole
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
private SshClient _sshConnection;
private ShellStream _shellStream;
private delegate void UpdateTextCallback(string message);
public MainWindow()
{
InitializeComponent();
}
/// <summary>
/// When the user presses connect, connect to the device
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Button_Click(object sender, RoutedEventArgs e)
{
try
{
// Connect to device
_sshConnection = new SshClient(hostname.Text, int.Parse(port.Text), username.Text, password.Text);
_sshConnection.Connect();
// Create a shell stream
_shellStream = _sshConnection.CreateShellStream("test", 80, 60, 800, 600, 65536);
MessageBox.Show("Connected!");
}
catch (Exception exception)
{
MessageBox.Show($"Error {exception.Message}");
}
}
/// <summary>
/// Start a new thread used to receive SSH data when the window is loaded
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Window_Loaded(object sender, RoutedEventArgs e)
{
ThreadStart threadStart = new ThreadStart(RecvSshData);
Thread thread = new Thread(threadStart);
thread.IsBackground = true;
thread.Start();
}
/// <summary>
/// Receive SSH data and write it to the textbox
/// </summary>
private void RecvSshData()
{
while (true)
{
try
{
if (_shellStream != null && _shellStream.DataAvailable)
{
string data = _shellStream.Read();
textBox.Dispatcher.Invoke(new UpdateTextCallback(UpdateText), data);
}
}
catch (Exception e)
{
Console.WriteLine(e);
}
Thread.Sleep(200);
}
}
/// <summary>
/// Write message to the textbox
/// </summary>
/// <param name="message"></param>
private void UpdateText(string message)
{
textBox.AppendText(message + "\r\n");
}
}
}
From what I have read in other posts it seems like this should work and should capture all of the data but it does not. There could be something I am doing wrong in my implementation or they may even be a better way to do it.
Any input with help or recommendations is appreciated.

Answer 1

I got it working to a certain extent. "StartRecording" begins to record the stream on a separate thread which works and just writes it to the console for now. This is able to receive all of the data that is printed to the terminal on my device.
The only issue that I am having now is that the data stops coming through after about a minute. I'm not sure what is happening yet but I think the ShellStream is disconnecting at some point and I'm not sure why.
private SshClient _sshClient;
private ShellStream _shellStream;
private StreamReader _reader;
private StreamWriter _writer;
public Recorder()
{
try
{
_sshClient = new SshClient(_hostname, _port, _username, _password);
_sshClient.Connect();
_shellStream = _sshClient.CreateShellStream("Terminal", 80, 60, 800, 600, 65536);
_reader = new StreamReader(_shellStream, Encoding.UTF8, true, 1024, true);
_writer = new StreamWriter(_shellStream) { AutoFlush = true };
}
catch (Exception e)
{
// TODO
Console.WriteLine(e);
}
}
/// <summary>
/// Begin recording the output of "routediagnostic on" command
/// </summary>
public void StartRecording()
{
try
{
IsRecording = true;
WriteStream("routediagnostic on");
// Start a background thread that will read in the data from the Pyng terminal
ThreadStart threadStart = ReceiveData;
Thread thread = new Thread(threadStart) {IsBackground = true};
thread.Start();
}
catch (Exception e)
{
// TODO
Console.WriteLine(e);
}
finally
{
IsRecording = false;
}
}
private void ReceiveData()
{
while (true)
{
try
{
if (_reader != null)
{
StringBuilder result = new StringBuilder();
string line;
while ((line = _reader.ReadLine()) != null)
{
result.AppendLine(line);
}
if (!string.IsNullOrEmpty(result.ToString()))
{
// TODO - Parse data at this point
Console.WriteLine(result.ToString());
}
}
}
catch (Exception e)
{
// TODO
Console.WriteLine(e);
}
Thread.Sleep(200);
}
}
private void WriteStream(string cmd)
{
_writer.WriteLine(cmd);
while (_shellStream.Length == 0)
{
Thread.Sleep(500);
}
}