CODEWITHSUNDEEP
node.js
J.D. Lowe
J.D. Lowe

Reputation: 133

node.js STDIN works with process.stdin, not when piped

I'm using require("child_process").spawn and calling an executable, which at the beginning is pausing for a password to be input; if I use it like below:

var spawn = require("child_process").spawn;
var exe = spawn("NameOfExe.exe", [/*arguments*/], {stdio: [process.stdin, process.stdout, process.stderr]});

It works perfectly (Yes, I know I can do inherit, shush :p ). I can type inside my console and it'll accept it with no issues.

However, if I do it like this:

var spawn = require("child_process").spawn;
var exe = spawn("NameOfExe.exe", [/*arguments*/], {stdio: ["pipe", process.stdout, process.stderr]});
exe.stdin.write("Password\n");

then the executable doesn't even receive the stdin; it immediately goes to Execution Failed.

I'm completely at a loss for this. Any suggestions?

EDIT:

I think I may be onto something!

So I'm 99.99% certain that the executable is using C# and Console.ReadKey to get the password. However, according to Microsoft, an exception gets thrown whenever the In property is redirected somewhere else.

So this explains it, but is there a way around this using Node, or am I at the mercy of the people who made this executable?

Upvotes: 1

Views: 265

Answers (1)

Dorn
Dorn

Reputation: 185

The ReadKey method reads from the keyboard even if the standard input is redirected to a file with the SetIn method.

You figured it out. It uses native bindings to the hardware controller/HAL, and not the shell, to handle stdio.

Upvotes: 1

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