How do I implement JWT authorization in a TypeScript Express app?

How do I implement JWT authorization in a TypeScript Express app?

To implement JWT authorization in a TypeScript Express app, you need to follow these steps: 1. Install necessary packages like jsonwebtoken and express-jwt. 2. Create a middleware function to verify the JWT. 3. Use this middleware in your routes to protect them.

Can you show me a code example for the middleware?

Sure! Here's a simple example of a JWT verification middleware:

import { Request, Response, NextFunction } from 'express';
import jwt from 'jsonwebtoken';

const secretKey = 'your_secret_key';

const authenticateJWT = (req: Request, res: Response, next: NextFunction) => {
    const token = req.header('Authorization')?.split(' ')[1];
    if (token) {
        jwt.verify(token, secretKey, (err, user) => {
            if (err) {
                return res.sendStatus(403);
            }
            req.user = user;
            next();
        });
    } else {
        res.sendStatus(401);
    }
};

This middleware checks for a token in the Authorization header and verifies it.

What should I do if the token is invalid?

If the token is invalid, you should respond with a 403 Forbidden status code. This indicates that the user is not authorized to access the requested resource.

How can I generate a JWT when a user logs in?

You can generate a JWT using the jsonwebtoken library. Here's an example:

const token = jwt.sign({ userId: user.id }, secretKey, { expiresIn: '1h' });

This will create a token that expires in one hour.