Capturing Intermediate Output in C# PowerShell CmdLet using yt-dlp

Question

How can intermediate status messages be displayed to the user and logged while executing the yt-dlp command in a C# CmdLet? I've created a System.Diagnostics.Process to execute yt-dlp, but I need to provide it access to the console for real-time output, similar to running it directly from the command line. Using Host.UI.WriteLine may strip colors, and I need to ensure that yt-dlp's dynamic updates to the console are visible. Additionally, I need to capture any JSON output that yt-dlp generates before it completes, which I believe will be in Standard Output. How can this be achieved?

Answer 1

You redirect standard output and error to streams to capture them. See

https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.process.standardoutput?view=net-9.0

Answer 2

Hi @Will Pittenger ,Welcome to Microsoft Q&A,

Have you seen the sample code in the related links? Try the code below and give me feedback.

using System;
using System.Diagnostics;
using System.Text;

public void RunYtDlp()
{
    // Set up the process start info
    var startInfo = new ProcessStartInfo
    {
        FileName = "yt-dlp",                     // Path to yt-dlp executable
        Arguments = "--your-arguments-here",     // Your arguments, e.g. URL, --dump-json, etc.
        UseShellExecute = false,                 // Must be false to redirect output
        CreateNoWindow = false,                  // Show a window if needed
        RedirectStandardOutput = true,           // Capture stdout (for JSON)
        // Leave StandardError not redirected so it goes directly to the console
    };

    var process = new Process { StartInfo = startInfo };

    // StringBuilder to accumulate JSON output (if needed)
    var jsonOutput = new StringBuilder();

    // Attach an asynchronous handler for stdout
    process.OutputDataReceived += (sender, e) =>
    {
        if (e.Data != null)
        {
            // Log or process the JSON output here
            jsonOutput.AppendLine(e.Data);
            // You can also write to a log file or update your UI here.
        }
    };

    // Start the process
    process.Start();

    // Begin reading stdout asynchronously
    process.BeginOutputReadLine();

    // Wait for yt-dlp to exit
    process.WaitForExit();

    // Now jsonOutput.ToString() contains the captured JSON output.
    // You can process it as needed.
    Console.WriteLine("Captured JSON output:");
    Console.WriteLine(jsonOutput.ToString());
}