Introduction to jwt-simple

jwt-simple is a lightweight and straightforward library for encoding and decoding JSON Web Tokens (JWT) in Node.js applications. It is perfect for developers looking to implement token-based authentication mechanisms without the need for complex dependencies.

API Examples

1. Installing jwt-simple

To get started with jwt-simple, you need to install it via npm:

  npm install jwt-simple  

2. Creating a JWT

This example demonstrates how to create a JWT using a secret key:

  const jwt = require('jwt-simple'); const payload = { userId: 123 }; const secret = 'my-secret'; const token = jwt.encode(payload, secret); console.log(token);  

3. Decoding a JWT

This example demonstrates how to decode a JWT:

  const decoded = jwt.decode(token, secret); console.log(decoded);  

4. Generating an Expiration Time

You can add an expiration time to your JWT for enhanced security:

  const payloadWithExpiry = {
  userId: 123,
  exp: Math.floor(Date.now() / 1000) + (60 * 60) // 1 hour expiration
}; const tokenWithExpiry = jwt.encode(payloadWithExpiry, secret); console.log(tokenWithExpiry);  

5. Verifying Token Integrity

To ensure that the token has not been tampered with, compare the secret used for encoding:

  try {
  const decoded = jwt.decode(tokenWithExpiry, 'incorrect-secret');
} catch (err) {
  console.error('Invalid token');
}  

Sample Application with jwt-simple

Below is a basic example of a Node.js application that demonstrates how to use jwt-simple to secure endpoints:

  const express = require('express'); const jwt = require('jwt-simple'); const app = express(); const secret = 'my-secret';
// Middleware to protect endpoints const authenticate = (req, res, next) => {
  const token = req.headers['authorization'];
  if (token) {
    try {
      const decoded = jwt.decode(token, secret);
      req.user = decoded;
      next();
    } catch (err) {
      res.status(401).send('Invalid token');
    }
  } else {
    res.status(401).send('No token provided');
  }
};
// Public endpoint app.get('/', (req, res) => {
  res.send('Welcome to the public API');
});
// Private endpoint app.get('/profile', authenticate, (req, res) => {
  res.json({ message: 'This is a protected route', user: req.user });
});
app.listen(3000, () => {
  console.log('Server is running on port 3000');
});  

Using jwt-simple lets you quickly add JWT-based authentication to your projects with minimal effort. Happy coding!

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