passport

library0.1.1jsnpmunverified

Passport is an Express-compatible authentication middleware for Node.js. It provides a simple, unobtrusive way to authenticate requests through an extensible set of 'strategies' (plugins) for various authentication methods like username/password, OAuth, or OpenID. It focuses solely on authentication, allowing developers to make application-level decisions about database schemas and routing. The current stable version is 0.7.0, and it is actively maintained.

auth-security web-framework

npm install passport

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INSTALL

IMPORT

SIG · PASSPORT

passport

auth-securityjavascriptv0.1.1

Install

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Import

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Disk

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Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

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glibc

node 18–226 runs

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Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

passport

✓ import passport from 'passport'

Also supports CommonJS: const passport = require('passport')

This quickstart demonstrates how to set up Passport with Express and a 'local' authentication strategy. It includes user serialization/deserialization for session management, a mock user database, and basic login/profile routes to show authentication in action. Users can access a protected profile route after logging in.

import express from 'express'; import session from 'express-session'; import passport from 'passport'; import { Strategy as LocalStrategy } from 'passport-local'; const app = express(); // Mock User database (in-memory) const users = [{ id: '1', username: 'testuser', password: 'password123' }]; // Configure Passport local strategy passport.use(new LocalStrategy( (username, password, done) => { const user = users.find(u => u.username === username); if (!user || user.password !== password) { return done(null, false, { message: 'Incorrect username or password.' }); } return done(null, user); } )); // Configure Passport session serialization/deserialization passport.serializeUser((user, done) => { done(null, user.id); }); passport.deserializeUser((id, done) => { const user = users.find(u => u.id === id); done(null, user); }); // Setup Express middleware app.use(session({ secret: process.env.SESSION_SECRET ?? 'a-very-secret-key', // Use a strong secret in production resave: false, saveUninitialized: false })); app.use(passport.initialize()); app.use(passport.session()); app.use(express.urlencoded({ extended: false })); // For form parsing // Example routes app.get('/login', (req, res) => { res.send('<form action="/login" method="POST">Username: <input name="username"/><br/>Password: <input type="password" name="password"/><br/><button type="submit">Login</button></form>'); }); app.post('/login', passport.authenticate('local', { successRedirect: '/profile', failureRedirect: '/login', failureMessage: true }) ); app.get('/profile', (req, res) => { if (!req.isAuthenticated()) { return res.redirect('/login'); } res.send(`Welcome, ${req.user.username}! This is your profile.`); }); app.listen(3000, () => console.log('Server running on port 3000')); // To run this example: // npm install express express-session passport passport-local // Add "type": "module" to your package.json for ESM support.

Debug

Known issues

gotchaPassport itself does not include any authentication logic or strategies. You must install and configure specific strategy packages (e.g., `passport-local`, `passport-google-oauth2`) separately for each authentication method you wish to use.

fix

Install the appropriate `passport-strategy-name` package(s) and register them with `passport.use(new Strategy(...))`.

affects: >=0.1.0

gotchaFor persistent login sessions, Passport requires a session middleware (like `express-session`) to be set up and integrated via `app.use(passport.initialize())` and `app.use(passport.session())`.

fix

Install `express-session` and ensure `app.use(session(...))`, `app.use(passport.initialize())`, and `app.use(passport.session())` are called in your Express app middleware chain.

affects: >=0.1.0

gotchaYou must implement `passport.serializeUser` and `passport.deserializeUser` functions for session management to work correctly. Without them, users cannot be stored in or retrieved from the session.

fix

Define `passport.serializeUser((user, done) => { done(null, user.id); });` and `passport.deserializeUser((id, done) => { /* fetch user by id */ done(null, user); });`

affects: >=0.1.0

gotchaThe `passport.authenticate()` middleware requires a string argument specifying the name of the strategy to use (e.g., 'local'). This name must correspond to a strategy previously registered with `passport.use()`.

fix

Ensure `passport.use(new MyStrategy({ name: 'my-strategy' }, ...))` is called, and then use `passport.authenticate('my-strategy', ...)`.

affects: >=0.1.0

gotchaStrategy callback functions (e.g., `LocalStrategy`'s `verify` function) must call the `done()` callback correctly to indicate success (`done(null, user)`), failure (`done(null, false)`), or an error (`done(err)`). Incorrect calls can lead to authentication issues or unhandled errors.

fix

Always call `done()` with the appropriate arguments. `done(null, false)` indicates failed login (e.g., bad credentials), `done(err)` for system errors, and `done(null, user)` for successful authentication.

affects: >=0.1.0

Errors

Common errors & fixes

Error: Passport is not initialized. To use Passport middleware, you must first call passport.initialize().

The `passport.initialize()` middleware was not added to the Express application.

fix

Add `app.use(passport.initialize());` before any routes or other Passport middleware.

Error: Failed to serialize user into session

The `passport.serializeUser` function was not defined or returned an invalid value.

fix

Implement `passport.serializeUser((user, done) => { done(null, user.id); });` (replace `user.id` with a unique identifier for your user).

Error: Failed to deserialize user from session

The `passport.deserializeUser` function was not defined or failed to retrieve a user for the provided ID.

fix

Implement `passport.deserializeUser((id, done) => { /* find user by id from your database */ done(null, user); });`

Error: Unknown authentication strategy "local"

The 'local' strategy (or any specified strategy) has not been registered with Passport using `passport.use()`.

fix

Ensure `passport.use(new LocalStrategy(...))` (or the equivalent for your chosen strategy) is called after importing the strategy and before `passport.authenticate()` is used.

TypeError: Cannot read properties of undefined (reading 'username')

Attempting to access `req.user` when no user is authenticated or `deserializeUser` failed to populate `req.user`.

fix

Ensure the user is properly authenticated, `passport.deserializeUser` is correctly implemented and fetching a user, and check `req.isAuthenticated()` before accessing `req.user`.

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Version history

0.1.1latest on npm

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Resources

githubhttps://github.com/jaredhanson/passport ↗

packagehttps://www.npmjs.com/package/passport ↗

homepagehttps://www.passportjs.org ↗