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C#: Calling a php script and beeing able to stop it

I am currently working on a C# Program which needs to call a local PHP script and write its output to a file. The problem is, that I need to be able to stop the execution of the script.
First, I tried to call cmd.exe and let cmd write the output to the file which worked fine. But I found out, that killing the cmd process does not stop the php cli.
So I tried to call php directly, redirect its output and write it from the C# code to a file. But here the problem seems to be, that the php cli does not terminate when the script is done. process.WaitForExit() does not return, even when I am sure that the script has been fully executed.
I cannot set a timeout to the WaitForExit(), because depending on the arguments, the script may take 3 minutes or eg. 10 hours.
I do not want to kill just a random php cli, there may be others currently running.
What is the best way to call a local php script from C#, writing its output to a file and beeing able to stop the execution?
Here is my current code:
// Create the process
var process = new System.Diagnostics.Process();
process.EnableRaisingEvents = true;
process.StartInfo.UseShellExecute = false;
process.StartInfo.FileName = "php.exe";
// CreateExportScriptArgument returns something like "file.php arg1 arg2 ..."
process.StartInfo.Arguments = CreateExportScriptArgument(code, this.content, this.options);
process.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
process.StartInfo.RedirectStandardOutput = true;
// Start the process or cancel, if the process should not run
if (!this.isRunning) { return; }
this.currentProcess = process;
process.Start();
// Get the output
var output = process.StandardOutput;
// Wait for the process to finish
process.WaitForExit();
this.currentProcess = null;
To kill the process I am using:
// Mark as not running to prevent starting new
this.isRunning = false;
// Kill the process
if (this.currentProcess != null)
{
this.currentProcess.Kill();
}
Thanks for reading!
EDIT
That the cli does not return seems to be not reproducible. When I test a different script (without arguments) it works, probably its the script or the passing of the arguments.
Running my script from cmd works just fine, so the script should not be the problem
EDIT 2
When disabling RedirectStandardOutput, the cli quits. could it be, that I need to read the output, before the process finishes? Or does the process wait, when some kind of buffer is full?
EDIT 3: Problem solved
Thanks to VolkerK, I / we found a solution. The problem was, that WaitForExit() did not get called, when the output is not read (probably due to a full buffer in the standard output). My script wrote much output.
What works for me:
process.Start();
// Get the output
var output = process.StandardOutput;
// Read the input and write to file, live to avoid reading / writing to much at once
using (var file = new StreamWriter("path\\file", false, new UTF8Encoding()))
{
// Read each line
while (!process.HasExited)
{
file.WriteLine(output.ReadLine());
}
// Read the rest
file.Write(output.ReadToEnd());
// flush to file
file.Flush();
}

Since the problem was that the output buffer was full and therefore the php process stalled while waiting to send its output, asynchronously reading the output in the c# program is the solution.
class Program {
protected static /* yeah, yeah, it's only an example */ StringBuilder output;
static void Main(string[] args)
{
// Create the process
var process = new System.Diagnostics.Process();
process.EnableRaisingEvents = true;
process.StartInfo.UseShellExecute = false;
process.StartInfo.FileName = "php.exe";
process.StartInfo.Arguments = "-f path\\test.php mu b 0 0 pgsql://user:pass#x.x.x.x:5432/nominatim";
process.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
process.StartInfo.RedirectStandardOutput = true;
output = new StringBuilder();
process.OutputDataReceived += process_OutputDataReceived;
// Start the process
process.Start();
process.BeginOutputReadLine();
// Wait for the process to finish
process.WaitForExit();
Console.WriteLine("test");
// <-- do something with Program.output here -->
Console.ReadKey();
}
static void process_OutputDataReceived(object sender, System.Diagnostics.DataReceivedEventArgs e)
{
if (!String.IsNullOrEmpty(e.Data)) {
// edit: oops the new-line/carriage-return characters are not "in" e.Data.....
// this _might_ be a problem depending on the actual output.
output.Append(e.Data);
output.Append(Environment.NewLine);
}
}
}
see also: https://msdn.microsoft.com/en-us/library/system.diagnostics.process.beginoutputreadline%28v=vs.110%29.aspx

How to redirect command prompt output to a file using asp.net C#?

I have tried to redirect the command prompt output to a file using Asp.Net C#.
System.Diagnostics.Process si = new System.Diagnostics.Process();
si.StartInfo.WorkingDirectory = "c:\\";
si.StartInfo.UseShellExecute = false;
si.StartInfo.FileName = "cmd.exe";
si.StartInfo.Arguments = #"/c dir" +">" + #"Myval.txt";
si.StartInfo.CreateNoWindow = true;
si.StartInfo.RedirectStandardInput = true;
si.StartInfo.RedirectStandardOutput = true;
si.StartInfo.RedirectStandardError = true;
si.Start();
string output = si.StandardOutput.ReadToEnd();
Response.Write(output);
si.Close();
The file is getting created successfully but no content present in it.
Even the variable Output returns nothing.
Help me to resolve this issue.

EDIT after being corrected:
I just tested on my machine and the code works perfectly. I apologize for not reading and testing carefully myself. Myval.txt is created and the DIR output is written into it.
The output variable is empty because you are rerouting any output by the DIR command into the txt file, so that's by design.
Please see if there are any locks on the txt file preventing it from being overwritten. Further than that, I can only guess that there is a security issue preventing the DIR command from running.

IIS7 - I tested this various ways including using a Batch file but the application isn't available on desktop. I can see the worker process and the exe running under my user name but with session id value of zero.

The following has worked for me through command prompt:
// Start the child process.
Process p = new Process();
// Redirect the output stream of the child process.
p.StartInfo.UseShellExecute = false;
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.FileName = "YOURBATCHFILE.bat";
p.Start();
// Do not wait for the child process to exit before
// reading to the end of its redirected stream.
// p.WaitForExit();
// Read the output stream first and then wait.
string output = p.StandardOutput.ReadToEnd();
p.WaitForExit();

command redirection issue

here is my code
//Create process
System.Diagnostics.Process pProcess = new System.Diagnostics.Process();
//strCommand is path and file name of command to run
pProcess.StartInfo.FileName = "ffmpeg.exe";
//strCommandParameters are parameters to pass to program
pProcess.StartInfo.Arguments = "-i " + videoName;
pProcess.StartInfo.UseShellExecute = false;
//Set output of program to be written to process output stream
pProcess.StartInfo.RedirectStandardOutput = true;
//Start the process
pProcess.Start();
//Get program output
string strOutput = pProcess.StandardOutput.ReadToEnd();
//Wait for process to finish
pProcess.WaitForExit();
The command works, but strOutput string is empty, results are shown within the console. Am I missing something here?

It's possible the program is writing its output to StandardError instead of StandardOutput. Try using .RedirectStandardError = true and then .pProcess.StandardError.ReadToEnd() to capture that output.
If you need the possibility of capturing both standard error and standard out in (roughly) the proper interleave, you will likely need to use the async versions with callbacks on OutputDataReceived and ErrorDataReceived and using BeginOutput/ErrorReadLine.

Try to capture Std Error too as on any event of error, it will be used instead.
//Set output of program to be written to process output stream
pProcess.StartInfo.RedirectStandardError = true;
pProcess.StartInfo.RedirectStandardOutput = true;
//Start the process
pProcess.Start();
//Wait for process to finish
pProcess.WaitForExit();
//Get program output
string strError = pProcess.StandardError.ReadToEnd();
string strOutput = pProcess.StandardOutput.ReadToEnd();
I just wonder why you wait for exit WaitForExit after reading the output, it should be in reversed order as your app may dump more until it finally completes the ops

C#: get external shell command result line by line

I am writing a C# winform application that starts a second process to execute shell commands like "dir" and "ping". I redirect the second process's output so my app can receive the command result. It roughly works fine.
The only problem is my winform app receives the command line output as a whole instead of line by line. For example, it has to wait for the external "ping" command to finish (which takes many seconds or longer) and then receives the whole output (many lines) at once.
What I want is the app receives the cmdline output in real-time, i.e. by lines not by block. Is this doable?
I am using this code to read the output:
while ((result = proc.StandardOutput.ReadLine()) != null)
But it does not work the way I expected.
Thanks in advance.
EDIT: here is the code I am using:
System.Diagnostics.ProcessStartInfo procStartInfo = new
System.Diagnostics.ProcessStartInfo("cmd", "/c " + command);
procStartInfo.WindowStyle = ProcessWindowStyle.Hidden;
// The following commands are needed to redirect the standard output.
procStartInfo.RedirectStandardOutput = true;
procStartInfo.UseShellExecute = false;
procStartInfo.CreateNoWindow = true;
// Now we create a process, assign its ProcessStartInfo and start it
System.Diagnostics.Process proc = new System.Diagnostics.Process();
proc.StartInfo = procStartInfo;
proc.Start();
// Get the output into a string
string result;
try {
while ((result = proc.StandardOutput.ReadLine()) != null)
{
AppendRtfText(result+"\n", Brushes.Black);
}
} // here I expect it to update the text box line by line in real time
// but it does not.

Have a look at the example in this msdn article on how to do the reading completly async.
Beyond that I expect your code does to read line by line now but the UI doesn't get any time to repaint (missing Application.DoEvents(); after updating the RTFTextBox

Instead of loop using while ((result = proc.StandardOutput.ReadLine()) != null) you should of using:
...
proc.OutputDataReceived += proc_DataReceived;
proc.Start();
proc.BeginOutputReadLine();
proc.WaitForExit();
This will start asynchronous reading the lines when they arrives, you then handle the lines read by e.Data in proc_DataReceived handler, since you are use BeginOutputReadline the e.Data will be a string lines.

This could be usefull:
http://social.msdn.microsoft.com/Forums/en-US/csharplanguage/thread/8d6cebfc-9b8b-4667-85b5-2b92105cd0b7/
http://www.dotnetperls.com/redirectstandardoutput

I had the same issue and got around it with the following. I found that if I had an error in the external app I was getting no output at all using the ReadToEnd() method, so switched to use the line by line streamreader. Will be switching over to use the answer provided by Saa'd though as that looks like the proper way to handle it.
Also found this solution: c# coding convention public/private contexts which provides for error handling at the same time and giving a fuller explanation to the use of externalApp.OutputDataReceived += (sender, args) => Console.WriteLine(args.Data);
Process externalApp = new Process();
externalApp.StartInfo.FileName = config.ExternalApps + #"\location\DeleteApp.exe";
externalApp.StartInfo.Arguments = Directory.GetCurrentDirectory() + #"\..\..\..\project\argumentsForDeleteApp.xml";
externalApp.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
externalApp.StartInfo.UseShellExecute = false;
externalApp.StartInfo.RedirectStandardOutput = true;
Console.Out.WriteLine(DateTime.UtcNow.ToLocalTime().ToString() +
":###### External app: " + externalApp.StartInfo.FileName + " - START");
externalApp.Start();
using (StreamReader reader = externalApp.StandardOutput)
{
while (!reader.EndOfStream)
{
string result = reader.ReadLine();
Console.Out.WriteLine(result);
}
}
externalApp.WaitForExit();

How to get the output of a System.Diagnostics.Process?

I run ffmpeg like this:
System.Diagnostics.Process p = new System.Diagnostics.Process();
p.StartInfo = new System.Diagnostics.ProcessStartInfo(ffmpegPath, myParams);
p.Start();
p.WaitForExit();
... but the problem is that the console with ffmpeg pops up and disappears right away, so I can't get any feedback. I don't even know if the process ran correctly.
So how can I either:
Tell the console to stay opened
Retrieve in the C# what the console
displayed

What you need to do is capture the Standard Output stream:
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.UseShellExecute = false;
// instead of p.WaitForExit(), do
string q = "";
while ( ! p.HasExited ) {
q += p.StandardOutput.ReadToEnd();
}
You may also need to do something similar with StandardError. You can then do what you wish with q.
It is a bit finicky, as I discovered in one of my questions
As Jon Skeet has pointed out, it is not smart performance-wise to use string concatenation like this; you should instead use a StringBuilder:
p.StartInfo.RedirectStandardOutput = true;
p.StartInfo.UseShellExecute = false;
// instead of p.WaitForExit(), do
StringBuilder q = new StringBuilder();
while ( ! p.HasExited ) {
q.Append(p.StandardOutput.ReadToEnd());
}
string r = q.ToString();

Lucas' answer has a race condition: If the process finishes quickly the while loop is left (or never entered) even if there is some output left, that is you might miss out on some data. To prevent that, another ReadToEnd should be done after the process exited.
(Note that in comparison to the old version of my answer, I can no longer see a need for WaitForExit once the process.HasExited flag is true, so this boils down to:)
using (var process = Process.Start(startInfo))
{
var standardOutput = new StringBuilder();
// read chunk-wise while process is running.
while (!process.HasExited)
{
standardOutput.Append(process.StandardOutput.ReadToEnd());
}
// make sure not to miss out on any remaindings.
standardOutput.Append(process.StandardOutput.ReadToEnd());
// ...
}

I know this question is old, but I'll add to it anyway.
If all you wish to do is display the output of a command line process, and you're spawning the process from a console window, you need only redirect the standard input (yes, I know it sounds wrong, but it works).
So:
System.Diagnostics.Process p = new System.Diagnostics.Process();
p.StartInfo = new System.Diagnostics.ProcessStartInfo(ffmpegPath, myParams);
p.UseShellExecute = false;
p.RedirectStandardInput = true;
p.Start();
p.WaitForExit();
Would do just fine.

For a more specific answer directly related to ffmpeg, passing the "-report" command into ffmpeg will make it dump a log into the current directory with what was said in the display of the process.
‘-report’
Dump full command line and console output to a file named
program-YYYYMMDD-HHMMSS.log in the current directory. This file can be
useful for bug reports. It also implies -loglevel verbose.
Note: setting the environment variable FFREPORT to any value has the
same effect.
From FFMpeg Documentation.