CORS issues with Passport.js for Spotify authentication despite correct settings

[mikezhang]

I’m experiencing problems with my setup for Spotify authentication using Passport.js. Every time I attempt to send an authentication request from my frontend, I encounter CORS issues, even though I think my CORS settings are configured correctly. I’ve also made sure that the redirect URLs in the Spotify application dashboard are accurate.

What’s perplexing is that none of the console.log outputs from my backend appear in the terminal, despite seeing the requests being made from the browser’s network section. The only workaround I’ve found is using a Chrome plugin to bypass CORS, but that’s not a viable solution.

Here’s a simplified version of my setup:

const express = require('express');
const passport = require('passport');
const SpotifyStrategy = require('passport-spotify').Strategy;
const cors = require('cors');

const app = express();

app.use(cors({
  origin: 'http://localhost:3000',
  credentials: true
}));

passport.use(new SpotifyStrategy({
  clientID: process.env.SPOTIFY_CLIENT_ID,
  clientSecret: process.env.SPOTIFY_CLIENT_SECRET,
  callbackURL: '/auth/spotify/callback'
}, (accessToken, refreshToken, expires_in, profile, done) => {
  console.log('This never shows up');
  return done(null, profile);
}));

app.get('/auth/spotify', passport.authenticate('spotify', {
  scope: ['user-read-email']
}));

Does anyone have suggestions on what might be going wrong?

[Nate_91Surf]

I’ve hit this same CORS nightmare with OAuth flows. If your console.log statements aren’t showing up, it’s probably not just a CORS issue - something’s blocking your requests before they even reach your backend. I spent hours debugging this exact thing and found my frontend was bypassing my server completely, hitting Spotify’s auth endpoints directly instead of going through my /auth/spotify route first. Double-check that your frontend is actually calling your own server routes, not trying to handle OAuth client-side. Also, verify your backend is running and reachable at the right port. I know it sounds basic, but those simple issues are easy to miss. Since your CORS plugin works, your server setup is probably fine - I’d bet it’s a routing problem.

[jess_brown]

hey, looks like you’re missing session middleware and passport.init. try adding app.use(require('express-session')({...})) and app.use(passport.initialize()) before your routes. without em, passport won’t work, and dat’s why you’re not seeing logs in console.

[Dave_17Sketch]

The Problem:

You’re experiencing CORS issues with your Spotify authentication setup using Passport.js. Your backend console.log statements aren’t appearing, even though browser network requests show attempts to reach your server. A Chrome CORS plugin works, suggesting the problem lies within your server-side configuration or routing, not strictly with CORS headers themselves.

Step-by-Step Guide:

1. Correct the callbackURL and Add the Callback Route Handler: The most likely issue is your callbackURL configuration and the missing callback route handler. Your callbackURL must be absolute and precisely match the URL you’ve registered in your Spotify application dashboard. Additionally, you need a route handler to process the callback from Spotify.

   Incorrect (from original code):

   callbackURL: '/auth/spotify/callback'
   

   Correct (replace YOUR_PORT with your actual port number):

   callbackURL: 'http://localhost:YOUR_PORT/auth/spotify/callback'
   

   Now, add the missing callback route handler:

   app.get('/auth/spotify/callback', passport.authenticate('spotify', { failureRedirect: '/' }), (req, res) => {
       res.redirect('http://localhost:3000');
   });
   

   Explanation: The passport.authenticate('spotify', { failureRedirect: '/' }) middleware handles the authentication process. If authentication fails, it redirects to the root path (/). The subsequent function handles successful authentication and redirects the user back to your frontend application. Make absolutely sure that http://localhost:YOUR_PORT/auth/spotify/callback is precisely added to your Spotify app’s Allowed Redirect URIs.

2. Verify your Server is Running and Reachable: Double-check that your backend server is running on the correct port (YOUR_PORT) and that it’s accessible from your frontend. Try accessing a simple route on your backend to verify network connectivity.

3. Ensure Session and Passport Middleware are Included: Add express-session middleware and initialize Passport before your authentication routes. Without these, Passport won’t function correctly.

   const session = require('express-session');
   
   app.use(session({
       secret: 'your-secret-key', // Replace with a strong secret key
       resave: false,
       saveUninitialized: true
   }));
   
   app.use(passport.initialize());
   app.use(passport.session());
   

4. Check Frontend Routing: Verify your frontend application is correctly sending requests to your backend’s /auth/spotify route. If your frontend is directly contacting Spotify’s API endpoints, this will bypass your server entirely.

Common Pitfalls & What to Check Next:

• Incorrect Port Numbers: Ensure consistency between your frontend’s requests, backend’s listen port, and your callbackURL.
• Firewall/Proxy Issues: A firewall or proxy server on your local machine or network might be blocking requests to your backend or Spotify’s servers.
• Typographical Errors: Carefully review all URLs and variable names for any typos.
• Environment Variables: Ensure your SPOTIFY_CLIENT_ID and SPOTIFY_CLIENT_SECRET environment variables are correctly set.
• Express Middleware Order: Make sure that all relevant middleware (e.g., cors, session, passport.initialize(), passport.session()) is used in the correct order.

Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!