Get password from input using node.js

Question

How to get password from input using node.js? Which means you should not output password entered in console.

Answer 1

Update 2015 Dec 13: readline has replaced process.stdin and node_stdio was removed from Node 0.5.10.

var BACKSPACE = String.fromCharCode(127);


// Probably should use readline
// https://nodejs.org/api/readline.html
function getPassword(prompt, callback) {
    if (prompt) {
      process.stdout.write(prompt);
    }

    var stdin = process.stdin;
    stdin.resume();
    stdin.setRawMode(true);
    stdin.resume();
    stdin.setEncoding('utf8');

    var password = '';
    stdin.on('data', function (ch) {
        ch = ch.toString('utf8');

        switch (ch) {
        case "\n":
        case "\r":
        case "\u0004":
            // They've finished typing their password
            process.stdout.write('\n');
            stdin.setRawMode(false);
            stdin.pause();
            callback(false, password);
            break;
        case "\u0003":
            // Ctrl-C
            callback(true);
            break;
        case BACKSPACE:
            password = password.slice(0, password.length - 1);
            process.stdout.clearLine();
            process.stdout.cursorTo(0);
            process.stdout.write(prompt);
            process.stdout.write(password.split('').map(function () {
              return '*';
            }).join(''));
            break;
        default:
            // More passsword characters
            process.stdout.write('*');
            password += ch;
            break;
        }
    });
}

getPassword('Password: ');

Answer 2

You can use the read module (disclosure: written by me) for this:

In your shell:

npm install read

Then in your JS:

var read = require('read')
read({ prompt: 'Password: ', silent: true }, function(er, password) {
  console.log('Your password is: %s', password)
})

Answer 3

To do this I found this excellent Google Group post

Which contains the following snippet:

var stdin = process.openStdin()
  , stdio = process.binding("stdio")
stdio.setRawMode()

var password = ""
stdin.on("data", function (c) {
  c = c + ""
  switch (c) {
    case "\n": case "\r": case "\u0004":
      stdio.setRawMode(false)
      console.log("you entered: "+password)
      stdin.pause()
      break
    case "\u0003":
      process.exit()
      break
    default:
      password += c
      break
  }
})

Answer 4

Here is my tweaked version of nailer's from above, updated to get a callback and for node 0.8 usage:

/**
 * Get a password from stdin.
 *
 * Adapted from <http://stackoverflow.com/a/10357818/122384>.
 *
 * @param prompt {String} Optional prompt. Default 'Password: '.
 * @param callback {Function} `function (cancelled, password)` where
 *      `cancelled` is true if the user aborted (Ctrl+C).
 *
 * Limitations: Not sure if backspace is handled properly.
 */
function getPassword(prompt, callback) {
    if (callback === undefined) {
        callback = prompt;
        prompt = undefined;
    }
    if (prompt === undefined) {
        prompt = 'Password: ';
    }
    if (prompt) {
        process.stdout.write(prompt);
    }

    var stdin = process.stdin;
    stdin.resume();
    stdin.setRawMode(true);
    stdin.resume();
    stdin.setEncoding('utf8');

    var password = '';
    stdin.on('data', function (ch) {
        ch = ch + "";

        switch (ch) {
        case "\n":
        case "\r":
        case "\u0004":
            // They've finished typing their password
            process.stdout.write('\n');
            stdin.setRawMode(false);
            stdin.pause();
            callback(false, password);
            break;
        case "\u0003":
            // Ctrl-C
            callback(true);
            break;
        default:
            // More passsword characters
            process.stdout.write('*');
            password += ch;
            break;
        }
    });
}