How do I implement JWT authentication in a Next.js application?

How do I implement JWT authentication in a Next.js application?

To implement JWT authentication in a Next.js app, you can follow these steps: 1. Install necessary packages like jsonwebtoken and next-auth. 2. Create an API route for login that generates a JWT. 3. Store the JWT in cookies or local storage. 4. Use middleware to protect your routes.

Can you show me a code example for generating a JWT?

Sure! Here's a simple example:

import jwt from 'jsonwebtoken';

const secretKey = 'your_secret_key';

const generateToken = (user) => {
  return jwt.sign({ id: user.id }, secretKey, { expiresIn: '1h' });
};

This function takes a user object and generates a JWT.

How do I verify the JWT on the server side?

You can verify the JWT using the same jsonwebtoken package. Here's an example:

const verifyToken = (token) => {
  return jwt.verify(token, secretKey);
};

This function will decode the token and return the payload if it's valid.

What should I do if the token is expired?

If the token is expired, you should prompt the user to log in again to obtain a new token. You can also implement a refresh token mechanism to allow users to refresh their session without logging in again.