Unexpected 401 Unauthorized Responses with OAuth2 in a React and Node.js Application
I'm getting frustrated with I've been working on this all day and I'm developing a web application using React for the frontend and Node.js with Express for the backend, implementing OAuth2 for authentication... I have successfully set up the initial authentication flow, where users can log in via Google and obtain an access token. However, I am working with unexpected `401 Unauthorized` responses when making API calls to my protected routes after the user logs in. Tracking down the scenario, I verified that the access token is being sent in the `Authorization` header like this: ```javascript const response = await fetch('https://myapi.com/protected-route', { method: 'GET', headers: { 'Authorization': `Bearer ${accessToken}`, 'Content-Type': 'application/json' } }); ``` Despite the token being valid and correctly formatted, the backend consistently responds with `401 Unauthorized`. On the server side, I have the middleware set up as follows: ```javascript const jwt = require('jsonwebtoken'); app.use((req, res, next) => { const token = req.headers['authorization']?.split(' ')[1]; if (!token) { return res.status(401).send('Unauthorized'); } jwt.verify(token, process.env.JWT_SECRET, (err, decoded) => { if (err) { return res.status(401).send('Unauthorized'); } req.user = decoded; next(); }); }); ``` I've double-checked my JWT secret and ensured that it matches the one used to sign the token. Additionally, I confirmed that the token hasn't expired by checking the `exp` claim, and I'm also using the latest versions of `jsonwebtoken` (8.5.1) and `express` (4.17.1). After some debugging, I noticed that if I manually decode the token using `jwt.decode(token)`, it shows the correct payload. However, when I attempt to verify it, it throws an behavior stating `invalid signature`. This leads me to believe there may be a mismatch in how the token is being signed versus how it's being verified. I’ve tried regenerating the tokens multiple times and even created a new OAuth app to ensure there aren’t any issues with the current configuration. It seems like I’m missing something fundamental regarding the secret or how the tokens are being issued. Any insights on what might be going wrong here? I'm using Javascript latest in this project. Thanks for taking the time to read this!