Basic HTTP authentication with Node and Express 4

It looks like implementing basic HTTP authentication with Express v3 was trivial:

app.use(express.basicAuth('username', 'password'));

Version 4 (I'm using 4.2) removed the basicAuth middleware, though, so I'm a little stuck. I have the following code, but it doesn't cause the browser to prompt the user for credentials, which is what I'd like (and what I imagine the old method did):

app.use(function(req, res, next) {
    var user = auth(req);

    if (user === undefined || user['name'] !== 'username' || user['pass'] !== 'password') {
        res.writeHead(401, 'Access invalid for user', {'Content-Type' : 'text/plain'});
        res.end('Invalid credentials');
    } else {
        next();
    }
});

Solution 1:

Simple Basic Auth with vanilla JavaScript (ES6)

app.use((req, res, next) => {

  // -----------------------------------------------------------------------
  // authentication middleware

  const auth = {login: 'yourlogin', password: 'yourpassword'} // change this

  // parse login and password from headers
  const b64auth = (req.headers.authorization || '').split(' ')[1] || ''
  const [login, password] = Buffer.from(b64auth, 'base64').toString().split(':')

  // Verify login and password are set and correct
  if (login && password && login === auth.login && password === auth.password) {
    // Access granted...
    return next()
  }

  // Access denied...
  res.set('WWW-Authenticate', 'Basic realm="401"') // change this
  res.status(401).send('Authentication required.') // custom message

  // -----------------------------------------------------------------------

})

_{note: This "middleware" can be used in any handler. Just remove next() and reverse the logic. See the 1-statement example below, or the edit history of this answer.}

Why?

• req.headers.authorization contains the value "Basic <base64 string>", but it can also be empty and we don't want it to fail, hence the weird combo of || ''
• Node doesn't know atob() and btoa(), hence the Buffer

ES6 -> ES5

const is just var .. sort of
(x, y) => {...} is just function(x, y) {...}
const [login, password] = ...split() is just two var assignments in one

source of inspiration (uses packages)

  // parse login and password from headers
  const b64auth = (req.headers.authorization || '').split(' ')[1] || ''
  const strauth = Buffer.from(b64auth, 'base64').toString()
  const splitIndex = strauth.indexOf(':')
  const login = strauth.substring(0, splitIndex)
  const password = strauth.substring(splitIndex + 1)

  // using shorter regex by @adabru
  // const [_, login, password] = strauth.match(/(.*?):(.*)/) || []

Basic auth in one statement

...on the other hand, if you only ever use one or very few logins, this is the bare minimum you need: (you don't even need to parse the credentials at all)

function (req, res) {
//btoa('yourlogin:yourpassword') -> "eW91cmxvZ2luOnlvdXJwYXNzd29yZA=="
//btoa('otherlogin:otherpassword') -> "b3RoZXJsb2dpbjpvdGhlcnBhc3N3b3Jk"

  // Verify credentials
  if (  req.headers.authorization !== 'Basic eW91cmxvZ2luOnlvdXJwYXNzd29yZA=='
     && req.headers.authorization !== 'Basic b3RoZXJsb2dpbjpvdGhlcnBhc3N3b3Jk')        
    return res.status(401).send('Authentication required.') // Access denied.   

  // Access granted...
  res.send('hello world')
  // or call next() if you use it as middleware (as snippet #1)
}

PS: do you need to have both "secure" and "public" paths? Consider using express.router instead.

var securedRoutes = require('express').Router()

securedRoutes.use(/* auth-middleware from above */)
securedRoutes.get('path1', /* ... */) 

app.use('/secure', securedRoutes)
app.get('public', /* ... */)

// example.com/public       // no-auth
// example.com/secure/path1 // requires auth

Solution 2:

TL;DR:

☒ express.basicAuth is gone
☒ basic-auth-connect is deprecated
☒ basic-auth doesn't have any logic
☒ http-auth is an overkill
☑ express-basic-auth is what you want

More info:

Since you're using Express then you can use the express-basic-auth middleware.

See the docs:

• https://www.npmjs.com/package/express-basic-auth

Example:

const app = require('express')();
const basicAuth = require('express-basic-auth');
 
app.use(basicAuth({
    users: { admin: 'supersecret123' },
    challenge: true // <--- needed to actually show the login dialog!
}));

Solution 3:

A lot of the middleware was pulled out of the Express core in v4, and put into separate modules. The basic auth module is here: https://github.com/expressjs/basic-auth-connect

Your example would just need to change to this:

var basicAuth = require('basic-auth-connect');
app.use(basicAuth('username', 'password'));