Server-side rendered applications are a popular choice for web development due to their ability to provide a fast and efficient user experience. When building a server-side rendered application, handling user authentication becomes a crucial aspect to consider. JWT (JSON Web Token) authentication is a widely used approach to secure web applications and APIs. In this blog post, we will explore how to handle JWT authentication in a server-side rendered application.

What is JWT Authentication?

JWT authentication is a stateless authentication mechanism that uses JSON Web Tokens to securely transmit information between parties. A JSON Web Token consists of three parts: a header, a payload, and a signature. The header contains information about the algorithm used to sign the token, the payload contains the data, and the signature verifies the authenticity of the token.

Implementing JWT Authentication in a Server-Side Rendered Application

Here are the steps to implement JWT authentication in a server-side rendered application:

1. User Registration and Login

Implement a user registration and login system where users can create an account and authenticate themselves with their credentials. Upon successful authentication, generate a JWT for the user.

2. Store JWT in Client-Side Storage

Once the JWT is generated, store it securely in client-side storage. You can use localStorage or sessionStorage to store the token in the browser’s storage.

// Storing JWT in localStorage
localStorage.setItem('jwtToken', token);

// Storing JWT in sessionStorage
sessionStorage.setItem('jwtToken', token);

3. Verify JWT on Server-Side

On the server-side, ensure that the JWT is valid and has not been tampered with. Verify the signature of the token using the secret key that was used to sign it. If the verification is successful, extract the user information from the payload and validate the user’s access rights.

4. Protecting Routes

In your server-side rendered application, protect certain routes that require authentication. Check for the presence of the JWT in the client-side storage before allowing access to those routes. If the JWT is not present or has expired, redirect the user to the login page.

// Checking for JWT before accessing protected routes
const token = localStorage.getItem('jwtToken');

if (!token) {
  // Redirect user to login page
  window.location.href = '/login';
} else {
  // Proceed with accessing protected route
}

5. Logout

Implement a logout functionality that clears the JWT from the client-side storage.

// Clearing JWT from localStorage
localStorage.removeItem('jwtToken');

// Clearing JWT from sessionStorage
sessionStorage.removeItem('jwtToken');

Conclusion

In this blog post, we have covered the basics of handling JWT authentication in a server-side rendered application. By implementing this authentication mechanism, you can secure your application and protect sensitive user information. Remember to handle user registration and login, store the JWT securely in client-side storage, verify the JWT on the server-side, protect routes, and provide a logout functionality. With this knowledge, you can develop robust and secure server-side rendered applications.

#jwt #authentication