1

I am trying to execute command prompt lines after connecting to remote unix server from a C# code. I have used the below code and which is working. However, I want the commands to execute completely before the next command line is taken. currently the execution of lines is faster and due to this, the result which I am getting is wrong.

Each command should complete the processing and then move to next command. In my C# web application, I have the below code on a button click event

SshClient sshclient = new SshClient(hostname, username, pwd);
  sshclient.Connect();
  ShellStream stream = sshclient.CreateShellStream("cmsd", 80, 24, 800, 600, 1024);
objclass.sendCommand("command1", stream).ToString();
 objclass.sendCommand("command2", stream).ToString();

The class file contains the methods as below:

public StringBuilder  sendCommand(string customCMD, ShellStream stream)
        {
            StringBuilder answer = new StringBuilder();
            answer.Clear();
            var reader = new StreamReader(stream);
            var writer = new StreamWriter(stream);
            writer.AutoFlush = true;
            WriteStream(customCMD, writer, stream);
            answer = ReadStream(reader);
            return answer;           
        }    

        private void WriteStream(string cmd, StreamWriter writer, ShellStream stream)
        {
            writer.WriteLine(cmd);
            while (stream.Length == 0)
            {
                Thread.Sleep(500);
            }
        }

        private StringBuilder ReadStream(StreamReader reader)
        {
            StringBuilder result = new StringBuilder();
            string line;
            while ((line = reader.ReadLine()) != null)
            {
                result.AppendLine(line);
            }
            return result;
        }

//Tried new code

public StringBuilder sendCommand(string customCMD, ShellStream stream)
        {
            StringBuilder answer = new StringBuilder();
            answer.Clear();
            answer.Length = 0;            

            var reader = new StreamReader(stream);
            var writer = new StreamWriter(stream);
            writer.AutoFlush = true;

            while (!stream.DataAvailable)
            {
                WriteStream(customCMD, writer, stream);
                Thread.Sleep(5000);
            }

            answer = ReadStream(reader);

            return answer;

        }
venkat14
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1 Answers1

3

You can try something similar to following code : 

using (var client = new SshClient(hostname, username, pwd))
{
    client.Connect();
    var cmd = client.CreateCommand("sleep 15s;echo 123");
    var asynch = cmd.BeginExecute();
    while (!asynch.IsCompleted)
    {
         //  Waiting for command to complete...
         Thread.Sleep(2000);
    }
    result = cmd.EndExecute(asynch);
    client.Disconnect();
}
jo_Veera
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  • I am not able to see a parameter as BeginExecute. I can see Begin.Expect – venkat14 Mar 13 '19 at 08:55
  • Which namespace are you using for SshClient ? I have tried through Renci.SshNet namespace and it gives the BeginExecute method. – jo_Veera Mar 13 '19 at 10:18
  • i am using the Renci. But I am not getting this – venkat14 Mar 13 '19 at 10:33
  • Now I remember, I had installed Renci.SshNet.Async package from nuget which added Renci.SshNet and Renci.SshNet.Async namespaces in the references. May be you can try installing Renci.SshNet.Async – jo_Veera Mar 13 '19 at 11:05
  • Not yet. I have added a new code in my original post. could you please review, if that can help to solve this issue. Issue is I need to wait for the prompt to move to next empty prompt and then read the data and show in browser UI and then write the next command – venkat14 Mar 13 '19 at 14:03
  • Look into following link : https://stackoverflow.com/questions/34204693/getting-full-command-output-from-shellstream-of-c-sharp-ssh-net The link says to use sshclient.CreateCommand instead of sshclient.CreateShellStream – jo_Veera Mar 13 '19 at 17:10
  • Additionally, `Task.Delay(2000);`is better option than `Thread.Sleep(2000)` in terms of performance. – Onurkan Bakırcı May 07 '23 at 06:09