Implementing Custom SSO

1. Introduction

Single Sign-On (SSO) is an authentication process that allows a user to access multiple applications with one set of login credentials. This lesson will guide you through implementing a custom SSO solution for front-end applications.

2. Key Concepts

3. Implementation Steps

1. Create an Authentication Server

   Set up a server that handles user authentication, generates tokens, and issues them to clients.

2. Integrate Front-End Applications

   Modify your front-end applications to support token-based authentication. Use libraries like Axios or Fetch to handle API calls.

3. Implement Token Handling

   Store the JWT securely in the browser (e.g., in HttpOnly cookies) and attach it to every request to your APIs.

   
       // Example of setting a JWT in a cookie
       document.cookie = "token=" + jwtToken + "; path=/; HttpOnly";
                       

4. Manage Session State

   Implement logic to check for token expiration and refresh tokens if necessary.

5. Secure Your Endpoints

   Ensure that all API endpoints validate the JWT and check user permissions before processing requests.

   
       // Example of validating JWT in an Express.js middleware
       const jwt = require('jsonwebtoken');
       
       function authenticateToken(req, res, next) {
           const token = req.cookies.token;
           if (!token) return res.sendStatus(401);
   
           jwt.verify(token, process.env.ACCESS_TOKEN_SECRET, (err, user) => {
               if (err) return res.sendStatus(403);
               req.user = user;
               next();
           });
       }
                       

4. Best Practices

• Always use HTTPS to protect token transmission.
• Implement token expiration and refresh mechanisms.
• Use short-lived tokens to minimize risk in case of token theft.
• Regularly review and update your security policies.

5. FAQ