passport-local

What is passport-local?

The passport-local npm package is a Passport strategy for authenticating with a username and password. It is designed to be simple and unopinionated, allowing developers to implement their own authentication logic.

What are passport-local's main functionalities?

Local Strategy Setup

This code sets up the LocalStrategy for Passport, which will authenticate users based on a username and password. The `User.findOne` function is a placeholder for your user lookup logic.

const passport = require('passport');
const LocalStrategy = require('passport-local').Strategy;

passport.use(new LocalStrategy(
  function(username, password, done) {
    User.findOne({ username: username }, function (err, user) {
      if (err) { return done(err); }
      if (!user) { return done(null, false, { message: 'Incorrect username.' }); }
      if (!user.validPassword(password)) { return done(null, false, { message: 'Incorrect password.' }); }
      return done(null, user);
    });
  }
));

Serialize and Deserialize User

These functions are used to serialize the user information into the session and deserialize it back. This is necessary for maintaining login sessions.

passport.serializeUser(function(user, done) {
  done(null, user.id);
});

passport.deserializeUser(function(id, done) {
  User.findById(id, function (err, user) {
    done(err, user);
  });
});

Middleware for Authentication

This code demonstrates how to use the `passport.authenticate` middleware in an Express route to handle user login. It redirects users based on the success or failure of the authentication.

app.post('/login',
  passport.authenticate('local', { successRedirect: '/', failureRedirect: '/login', failureFlash: true })
);

Other packages similar to passport-local

passport-jwt

The passport-jwt package is a Passport strategy for authenticating with a JSON Web Token. It is used for stateless authentication, where the token is usually sent in the HTTP headers. Unlike passport-local, which uses sessions, passport-jwt is suitable for APIs and mobile applications.

passport-oauth2

The passport-oauth2 package is a Passport strategy for authenticating with OAuth 2.0. It is used for third-party authentication providers like Google, Facebook, and GitHub. This package is more complex than passport-local as it involves redirecting users to the provider's site for authentication.

passport-google-oauth20

The passport-google-oauth20 package is a Passport strategy for authenticating with Google using OAuth 2.0. It is specifically tailored for Google authentication and provides a streamlined way to integrate Google login into your application, unlike passport-local which is for username and password authentication.

README

passport-local

Passport strategy for authenticating with a username and password.

This module lets you authenticate using a username and password in your Node.js applications. By plugging into Passport, local authentication can be easily and unobtrusively integrated into any application or framework that supports Connect-style middleware, including Express.

Install

$ npm install passport-local

Usage

Configure Strategy

The local authentication strategy authenticates users using a username and password. The strategy requires a verify callback, which accepts these credentials and calls done providing a user.

passport.use(new LocalStrategy(
  function(username, password, done) {
    User.findOne({ username: username }, function (err, user) {
      if (err) { return done(err); }
      if (!user) { return done(null, false); }
      if (!user.verifyPassword(password)) { return done(null, false); }
      return done(null, user);
    });
  }
));

Authenticate Requests

Use passport.authenticate(), specifying the 'local' strategy, to authenticate requests.

For example, as route middleware in an Express application:

app.post('/login', 
  passport.authenticate('local', { failureRedirect: '/login' }),
  function(req, res) {
    res.redirect('/');
  });

Examples

For complete, working examples, refer to the multiple examples included.

Tests

$ npm install
$ npm test

Credits

• Jared Hanson

License

The MIT License

Copyright (c) 2011-2014 Jared Hanson <http://jaredhanson.net/>