Native error in .NET Core Blazor WebAssembly

Question

My task is to run a CLI command (in the client's system) and to show the output to the user on the Web app. [assume, a web-based cmd.exe]

Based on reading about WebAssembly's capabilities, I used the .NET CORE Blazor WebAssembly to do the task. But using the System.Diagnostics.ProcessStartInfo in Client throws runtime error Native error= Cannot find the specified file.

Please let me know if my understanding of WebAssembly is wrong. Also, suggest how I could accomplish the task?

Code used in Razor page:

protected override async Task OnInitializedAsync()
{
    quiz = await Http.GetJsonAsync<List<QuizItem>>("Quiz");

    // My actual code...
    string process = @"C:\Windows\System32\cmd.exe", arguments = "start", workingFolder = ".";
    System.Diagnostics.ProcessStartInfo startinfo = new System.Diagnostics.ProcessStartInfo {
        FileName = process, Arguments = arguments, WorkingDirectory = workingFolder,
        CreateNoWindow = false, UseShellExecute = false,
        RedirectStandardError = true, RedirectStandardOutput = true,
    };
    System.Diagnostics.Process proc = System.Diagnostics.Process.Start (startinfo);
    if (proc == null) throw new Exception ($"Unable to execute '{process}'");
}

Console log for reference:

Imagine what a security threat this would be. Open a website and suddenly someone accesses your filesystem without any interaction of you. — Joelius

Flores Flores · Accepted Answer · 2020-02-04T10:07:54

The permissions of blazor are limited by the browser javascript sandbox, so you cannot do anything you also cannot do in javascript. Starting processes is one of them.

Native error in .NET Core Blazor WebAssembly

2 Answers