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C# Process.StandardOutput.Peek not working

I need to use standard input/output on process, so I created simple app "test":
var line = String.Empty;
do
{
Console.Write($"previous input ==> {line}, type next input> ");
line = Console.ReadLine();
}
while (!String.IsNullOrWhiteSpace(line) && line != "quit");
Console.WriteLine("End");
which receives something on standard input and writes on output. Then I created new app which needs to start that app "test" and use standard iput/output like:
var process = new Process
{
EnableRaisingEvents = false,
StartInfo = new ProcessStartInfo
{
UseShellExecute = false,
RedirectStandardOutput = true,
RedirectStandardError = true,
RedirectStandardInput = true,
Arguments = Arguments,
CreateNoWindow = true,
FileName = Name,
WindowStyle = ProcessWindowStyle.Hidden,
WorkingDirectory = WorkingDirectory
},
};
process.Start();
String? input;
do
{
Thread.Sleep(10000); // Sleep to be sure that "test" app generated output
var line = String.Empty;
while (process.StandardOutput.Peek() > -1)
line += (char)process.StandardOutput.Read();
Console.Write($"[Standard Output]{line}\t[New Input]");
input = Console.ReadLine();
process.StandardInput.WriteLine(input);
}
while (input != "quit");
The problem is that I get this as output:
[Standard Output]previous input ==> , type next input> [New Input]test
[Standard Output] [New Input]
The "process.StandardOutput.Peek()" second time is returning -1 and there exist output of "test" app. Is it possible to get next what is generated on standard output by "test" app from app that started that process.
I need to get second output generated from "test" app, so I expect to see line:
[Standard Output]previous input ==> test, type next input> [New Input]

If your platform is Windows, try PeekNamedPipe.
static string ReadAvailableString(StreamReader reader)
{
[DllImport("kernel32.dll")]
static extern bool PeekNamedPipe(
SafeFileHandle hNamedPipe,
IntPtr lpBuffer,
int nBufferSize,
IntPtr lpBytesRead,
out int lpTotalBytesAvail,
IntPtr lpBytesLeftThisMessage
);
var stream = (FileStream)reader.BaseStream;
if( !PeekNamedPipe(stream.SafeFileHandle, IntPtr.Zero, 0, IntPtr.Zero, out var totalbytesAvail, IntPtr.Zero) || totalbytesAvail<=0 )
return String.Empty;
Span<byte> buf = stackalloc byte[totalbytesAvail];
stream.Read(buf);
return reader.CurrentEncoding.GetString(buf);
}
Here is an example of getting StandardOutput.
var output = ReadAvailableString(process.StandardOutput);

Problem is Peek is non-blocking call which does not wait for data to become available. You start new process and then immediately proceed checking its standard output with Peek, but it might be nothing there yet. This is what you observe. Instead - you should read until some stopping point, but in this case there is no such point, so you can introduce it - use Console.WriteLine instead of Console.Write here:
Console.WriteLine($"previous input ==> {line}, type next input> ");
Now on receiving end you can read until you meet newline character:
line = process.StandardOutput.ReadLine();
Note that this is blocking read. It will read until newline, and if data is not available yet - it will wait until it's there. Now "messages" in your communication have clear boundaries.
I would even say that you should forget that Peek() exist and never use it. I've never used it in my practice and all usages I ever saw lead to bugs like this.

After trying a lot of things it seams that Process.StandardOutput.Peek is not working. You can use the "PeekNamedPipe" (answer from radian) for Windows OS.
I managed to work it on Windows and Linux using CliWrap (https://github.com/Tyrrrz/CliWrap). The problem here is that for input stream you need Stream that has blocking read() method, so I creted/implemented one for me. I will not put here the implementation of that stream, you can use any stream that satisfy that condition. So, here is the final version of above example using CliWrap library
var stdOutBuffer = new StringBuilder();
var stdErrBuffer = new StringBuilder();
// The CliStream is my own implementation of Stream class.
// The CliWrap library is calling method: int Read(byte[] buffer, int offset, int count)
// with parameters offset = 0 and count = 131072
// it is important that this method is blocking if nothing is in stream (it done it using Semaphores)
// if it is not blocking then you will have some unexpected behaviour
var stream = new CliStream();
var cmd = CliWrap.Cli.Wrap(ExecName)
.WithArguments(Arguments)
.WithStandardErrorPipe(CliWrap.PipeTarget.ToStringBuilder(stdErrBuffer))
.WithStandardOutputPipe(CliWrap.PipeTarget.ToStringBuilder(stdOutBuffer))
.WithStandardInputPipe(CliWrap.PipeSource.FromStream(stream))
.WithWorkingDirectory(WorkingDirectory);
cmd.ExecuteAsync();
String? input;
do
{
Thread.Sleep(10000); // Sleep to be sure that "test" app generated output
Console.Write($"[Standard Output]{stdOutBuffer}\t[New Input]");
stdOutBuffer.Clear();
input = Console.ReadLine();
var buffer = Encoding.UTF8.GetBytes(input + Environment.NewLine);
stream.Write(buffer);
}
while (input != "quit");
Thanks to everyone for contributing.

-ERR Exceeded the login limit for a 15 minute period. Reduce the frequency of requests to the POP3 server

using following code i have reading msg from my hotmail account . But sometimes the following error coming . -ERR Exceeded the login limit for a 15 minute period. Reduce the frequency of requests to the POP3 server . can anyone tell me whats the reason for this ? Is that server problem or anything else ? other than pop3 anyother protocol can we use for hotmail?
public string hotmail(string username, string password)
{
string result = "";
string str = string.Empty;
string strTemp = string.Empty;
try
{
TcpClient tcpclient = new TcpClient();
tcpclient.Connect("pop3.live.com", 995);
System.Net.Security.SslStream sslstream = new SslStream(tcpclient.GetStream());
sslstream.AuthenticateAsClient("pop3.live.com");
System.IO.StreamWriter sw = new StreamWriter(sslstream);
System.IO.StreamReader reader = new StreamReader(sslstream);
strTemp = reader.ReadLine();
sw.WriteLine("USER" + " " + username);
sw.Flush();
strTemp = reader.ReadLine();
sw.WriteLine("PASS" + " " + password);
sw.Flush();
strTemp = reader.ReadLine();
string[] numbers = Regex.Split(strTemp, #"\D+");
int a = 0;
foreach (string value in numbers)
{
if (!string.IsNullOrEmpty(value))
{
int i = int.Parse(value);
numbers[a] = i.ToString();
a++;
}
}
sw.WriteLine("RETR" + " " + numbers[0]);
sw.Flush();
strTemp = reader.ReadLine();
while ((strTemp = reader.ReadLine()) != null)
{
if (strTemp == ".")
{
break;
}
if (strTemp.IndexOf("-ERR") != -1)
{
break;
}
str += strTemp;
}
sw.WriteLine("Quit ");
sw.Flush();
result = str;
return result;
}
Catch ( Exception ex)
{}
return result;
}
thanks in advance ..

Any other protocol you can use? Yes, hotmail/outlook.com now supports IMAP.
But the issue with the code here seems to be that you're creating a new TcpClient every time you run this. If you're running it many times in in a row, Outlook.com/Hotmail will eventually complain. It's as if you've got tons of clients from a single source connecting to their server, which is, when it's not testing code, often a sign of email abuse.
TcpClient tcpclient = new TcpClient(); // Hello, new.
tcpclient.Connect("pop3.live.com", 995);
If you've got a lot to do on the server, keep a single connection active longer, and close it up when you're done.
Every time you run the code in your question, you're creating (and not tcpclient.Close()-ing) a connection to pop3.live.com. I usually only get this error when I've had a lot of connections that don't close properly due to errors when I'm messing with my code.
MSDN actually has a decent example for TcpClient, but you might be more interested in another example from SO here. Check out how it uses using, and nests a loop inside.
using (TcpClient client = new TcpClient())
{
client.Connect("pop3.live.com", 995);
while(variableThatRepresentsRunning)
{
// talk to POP server
}
}
By the way, the best advice I can give here is to tell you not to reinvent the wheel (unless you're just having fun playing with the POP server. Throwing commands via TCP can be lots of fun, especially with IMAP).
OpenPop.NET is a great library to handle POP requests in C#, includes a good MIME parser, and, if you're still working on this, should speed you along quite a bit. Its examples page is excellent.

Go to the mail inbox , you may get mail regarding this and accept it. Otherwise Try to give the request after some time. Because google having some restriction to read mail using pop settings.

How can I capture, log and display the console output of any arbitrary process with my own c# app?

I want to run on a C# program a specific running file and during it display the output on the screen and also saving it in the file.
I don't want to save the output in the file and later display it on screen.
I want them both to happen together.
I know a way to do it by "tee" but I failed each time I tried doing so.
Can anyone give me an example (that works) by using "tee"?

The main question is, do you have control over the source code of the program whose output you want logged and displayed?
If so, then you have a couple options. Probably the easiest would be to "hijack" the Console's output stream with a compound TextWriter:
public class CompoundWriter:TextWriter
{
public readonly List<TextWriter> Writers = new List<TextWriter>();
public override void WriteLine(string line)
{
if(Writers.Any())
foreach(var writer in Writers)
writer.WriteLine(line);
}
//override other TextWriter methods as necessary
}
...
//When the program starts, get the default Console output stream
var consoleOut = Console.Out;
//Then replace it with a Compound writer set up with a file writer and the normal Console out.
var compoundWriter = new CompoundWriter();
compoundWriter.Writers.Add(consoleOut);
compoundWriter.Writers.Add(new TextWriter("c:\temp\myLogFile.txt");
Console.SetOut(compoundWriter);
//From now on, any calls to Console's Write methods will go to your CompoundWriter,
//which will send them to the console and the file.
You can also use the Trace listeners to handle any output you want to go to both places:
Trace.Listeners.Clear();
Trace.Listeners.Add(new TextWriterTraceListener(Console.Out));
Trace.Listeners.Add(new TextWriterTraceListener(File.Open("C:\temp\myLogFile.txt");
//replace any call to Console.WriteLine() with Trace.WriteLine()
if you do NOT have control over the source code of the console app you want to "tee", and the console app does not require any input in the middle of its execution, then you can use a named pipe to get the output of the app and redirect it.
var appLocation = #"C:\temp\myApp.exe";
var pipeName = "ConsoleNamedPipe";
using(var namedPipe = new NamedPipeServerStream(pipeName, PipeDirection.In))
{
var info = new ProcessStartInfo
{
FileName = "cmd.exe",
Arguments = String.Format(#"/C {1} >>\\.\pipe\{0}",
pipeName, appLocation),
WindowStyle = ProcessWindowStyle.Hidden
};
ConsoleProcess = Process.Start(info);
pipe.WaitForConnection();
using (var reader = new StreamReader(pipe))
{
while (!reader.EndOfStream)
{
var line = reader.ReadLine();
Console.WriteLine(line);
myFileWriter.WriteLine(line);
}
}
}
This is a very simple example; you can provide more interaction by using a two-way pipe but it will require quite a bit more code on your end.

You can try the following:
C:\you_csharp_program.exe arg1 arg2 arg3 |tee filename

I'm not going to write out specific code examples but I will tell you that you can look at logging frameworks like log4net which has console and file appenders which will do what you want. You cant wrong log statements in your code Log.Debug("some message") setup the log4net config to use any number of appenders you want and have it write the message to all of the sources at once, so for example screen, file, db, and email you all at the same time.
I seem to have missed the last sentence of the question about making it work with Tee so my answer may not be valid.

Elaborating on KeithS's answer, this is a working implementation. It should work for all Write/WriteLine calls without having to override every overload because the current (4.0, and I assume earlier) implementation of TextWriter directs all writes through Write(char).
public class TeeTextWriter : TextWriter
{
readonly TextWriter[] _redirectTo;
public override Encoding Encoding { get { return Encoding.UTF8; } }
public TeeTextWriter(params TextWriter[] redirectTo)
{
_redirectTo = redirectTo ?? new TextWriter[0];
}
public override void Write(char value)
{
foreach (var textWriter in _redirectTo)
{
textWriter.Write(value);
}
}
}
Usage:
var realConsoleStream = Console.Out;
using (var fileOut = new StreamWriter(outFileName, false))
{
Console.SetOut(new TeeTextWriter(fileOut, realConsoleStream));
try
{
Console.WriteLine("Test");
}
finally
{
Console.SetOut(realConsoleStream);
}
}

Execute a command line utility in ASP.NET

I need some advice regarding the use of a command line utility from a C#/ASP.NET web application.
I found a 3rd party utility for converting files to CSV format. The utility works perfectly and it can be used from the command line.
I have been looking on the web for examples on how to execute the command line utility and found this example.
The problem is this is not very good. When I try to us the example code with my utility, I get a prompt asking me to install the utility on the client machine. This is not what I want. I do not want the user to see what is going on in the background.
Is it possible to execute the command server side and processing the file from there?
Any help would be greatly appreciated.

I've done something like this several times in the past, and here's what's worked for me:
Create an IHttpHandler implementation (easiest to do as an .ashx file) to handle a convert. Within the handler, use System.Diagnostics.Process and ProcessStartInfo to run your command line utility. You should be able to redirect the standard output to the output stream of your HTTP response. Here's some code:
public class ConvertHandler : IHttpHandler
{
#region IHttpHandler Members
bool IHttpHandler.IsReusable
{
get { return false; }
}
void IHttpHandler.ProcessRequest(HttpContext context)
{
var jobID = Guid.NewGuid();
// retrieve the posted csv file
var csvFile = context.Request.Files["csv"];
// save the file to disk so the CMD line util can access it
var filePath = Path.Combine("csv", String.Format("{0:n}.csv", jobID));
csvFile.SaveAs(filePath);
var psi = new ProcessStartInfo("mycsvutil.exe", String.Format("-file {0}", filePath))
{
WorkingDirectory = Environment.CurrentDirectory,
UseShellExecute = false,
RedirectStandardOutput = true,
RedirectStandardError = true,
CreateNoWindow = true
};
using (var process = new Process { StartInfo = psi })
{
// delegate for writing the process output to the response output
Action<Object, DataReceivedEventArgs> dataReceived = ((sender, e) =>
{
if (e.Data != null) // sometimes a random event is received with null data, not sure why - I prefer to leave it out
{
context.Response.Write(e.Data);
context.Response.Write(Environment.NewLine);
context.Response.Flush();
}
});
process.OutputDataReceived += new DataReceivedEventHandler(dataReceived);
process.ErrorDataReceived += new DataReceivedEventHandler(dataReceived);
// use text/plain so line breaks and any other whitespace formatting is preserved
context.Response.ContentType = "text/plain";
// start the process and start reading the standard and error outputs
process.Start();
process.BeginErrorReadLine();
process.BeginOutputReadLine();
// wait for the process to exit
process.WaitForExit();
// an exit code other than 0 generally means an error
if (process.ExitCode != 0)
{
context.Response.StatusCode = 500;
}
}
}
#endregion
}

The command is running server side. Any code is running on the server. The code in the example that you give works. You just need to make sure that the utility is set up properly on the server and that you have permissions to the directory/file.

Multiple Download/Upload parallely in FTP using C#

I want to do Multiple Download/Upload parallely in FTP using C# without using FTPWebRequest.
I have written my custom code and when i try to download two files simultaneously first one get download properly while second one shows size as 0 KB(it also downloads).
public void sendCommand(String command, params string[] strfilename)
{
if (command == "RETR ") //Downloading file from Server
{
FileStream output = null;
if (!File.Exists(strfilename[0]))
output = File.Create(strfilename[0]);
else
output = new FileStream(strfilename[0] , FileMode.Open);
command = "RETR " + strfilename[0];
Byte[] cmdBytes = Encoding.ASCII.GetBytes((command + "\r\n").ToCharArray());
clientSocket.Send(cmdBytes, cmdBytes.Length, 0);
Socket csocket = createDataSocket();
DateTime timeout = DateTime.Now.AddSeconds(this.timeoutSeconds);
while (timeout > DateTime.Now)
{
this.bytes = csocket.Receive(buffer, buffer.Length, 0);
output.Write(this.buffer, 0, this.bytes);
if (this.bytes <= 0)
{
break;
}
}
// this.BinaryMode = true;
output.Close();
if (csocket.Connected) csocket.Close();
this.readResponse();
MessageBox.Show("File Downloaded successfully");
else if....so on
}
}
In my main method i do like this:
ftpcommand.sendCommand("RETR ","RMSViewer.xml"); //Downloading from Server
ftpcommand.sendCommand("RETR ","cms.xml");//Downloading from Server
Any code snippet....

As Dave said, you'd need separate instances of your ftpCommand class. Look into use the BackgroundWorker to run the commands in the background (asynchronously).

How are you issuing your requests simultaneously?
Threaded?
If so - you may want to ensure you're creating separate instances of your "ftpcommand" class.
I think we'll need more information to be able to help you :)