README.md

JWT Token-Based Authentication with React and Node.js

This repository demonstrates how to implement JWT token-based authentication in a React and Node.js application. It includes a server-side code (server.js) and a client-side code (App.js).

Server-side code (server.js)

This code sets up a simple Express.js server with two routes: /login for user authentication and /protected for accessing protected data.

// Server-side code
// ...

// Set up routes
app.post('/login', (req, res) => {
  // User authentication logic
  // ...
});

app.get('/protected', authenticateToken, (req, res) => {
  // Access protected data
  // ...
});

// ...

// Middleware for token authentication
function authenticateToken(req, res, next) {
  // Token verification logic
  // ...
}

// Start the server
app.listen(5000, () => {
  console.log('Server is running on http://localhost:5000');
});

Client-side code (App.js)

This code sets up a React component called App that interacts with the server-side API.

• The component uses React's useState hook to manage the token state.

• The handleLogin function sends a POST request to the server's /login endpoint with the username and password. If the login is successful, it stores the received JWT token in the component's state and saves it in the client-side storage (localStorage).

• The handleProtectedData function sends a GET request to the server's /protected endpoint with the JWT token in the Authorization header. If the request is successful, it displays the protected data; otherwise, it shows an error message.

• The handleLogout function clears the token from the component's state and removes it from the client-side storage, effectively logging out the user.

• The useEffect hook is used to check if a token exists in the client-side storage when the app loads. If a token is found, it is set in the component's state.

• The component's render function includes buttons for login, accessing protected data, and logout.

Steps to run the repository locally

1. Clone the repository to your local machine && Navigate to Backend :

cd backend && npm install

2. Start the backend server :

node server.js

3. Go back to main folder :

cd ..

4.Navigate to frontend :

cd frontend &&  npm install

5. Start the frontend server :

npm start