Run npm init from the c# console app

问题

I have try to run "npm init" command from the c# console app, using this code:

private void Execute(string command, string arg)
    {
        Process p = new Process();
        p.StartInfo.FileName = command;
        p.StartInfo.Arguments = arg;
        p.StartInfo.UseShellExecute = false;
        p.StartInfo.RedirectStandardOutput = true;
        p.StartInfo.RedirectStandardInput = true;
        p.StartInfo.WorkingDirectory = @"E:\Work\";  
        p.Start();
        p.WaitForExit();
    }

    Execute(@"C:\Program Files\nodejs\npm.cmd", "init");

But nothing happening. I getting only 2 empty lines after the running my app. Please, help to resolve this problem.

回答1:

Take a look at my example of running the npm run dist command.

var psiNpmRunDist = new ProcessStartInfo
{
    FileName = "cmd",
    RedirectStandardInput = true,
    WorkingDirectory = guiProjectDirectory
};
var pNpmRunDist = Process.Start(psiNpmRunDist);
pNpmRunDist.StandardInput.WriteLine("npm run dist & exit");
pNpmRunDist.WaitForExit();

回答2:

You'll need to capture the Process.StandardOutput: ProcessStartInfo.RedirectStandardOutput

Like this:

p.Start();

// To avoid deadlocks, always read the output stream first and then wait.
string output = p.StandardOutput.ReadToEnd();
p.WaitForExit();

Although, since NPM can be a long running process, you may want to wire up an event handler like in these samples: Realtime Console Output Redirection using Process

回答3:

The following works for me:

private static string RunCommand(string commandToRun, string workingDirectory = null)
{
    if (string.IsNullOrEmpty(workingDirectory))
    {
        workingDirectory = Directory.GetDirectoryRoot(Directory.GetCurrentDirectory());
    }

    var processStartInfo = new ProcessStartInfo()
    {
        FileName = "cmd",
        RedirectStandardOutput = true,
        RedirectStandardInput = true,
        WorkingDirectory = workingDirectory
    };

    var process = Process.Start(processStartInfo);

    if (process == null)
    {
        throw new Exception("Process should not be null.");
    }

    process.StandardInput.WriteLine($"{commandToRun} & exit");
    process.WaitForExit();

    var output = process.StandardOutput.ReadToEnd();
    return output;
}

You would use this like so:

var initResult = RunCommand("npm run init", @"E:\Work\");

This works for dotnet core as well as the standard .net framework.

回答4:

I have resolved this problem like this:

foreach (string s in commands)
{
   proc = Process.Start("npm.cmd", s);
   proc.WaitForExit();
}

回答5:

npm init prompts for several user inputs on a new project. For example, the project name, version, author, etc. These values are expected on StandardInput. You are correctly redirecting StandardInput, but I do not see you providing these values here. NPM will block until it receives this input, which is likely why you are seeing the application freeze. You will need to use WriteLine to provide the answers to NPM's questions in order to move forward, or at a minimum a blank WriteLine for each question will suffice. You can do this by calling p.StandardInput.WriteLine.

On my version of NPM (3.8.6), the following questions are asked:

name: (foo) 
version: (1.0.0) 
description: 
entry point: (index.js) 
test command: 
git repository: 
keywords: 
author: 
license: (ISC)

In addition to this, NPM will prompt with an "Are you sure?" at the end.

来源：https://stackoverflow.com/questions/37194302/run-npm-init-from-the-c-sharp-console-app

标签

node.js

npm

console-application