While building backend for Banking app, ecommerce, Admin dashboard or SaaS Platform. We have to figure out these problems:

• User Must login securely [we can use JWT authentication]
• Passwords must be safe [Password Hashing]
• Only admin access admin APIs [Role based access]
• Prevent Brute Force login [Rate limiting]
• Avoiding hitting database repeatedly [Redis caching]
• Secure APIs [Spring security]
• Deploy easily [Using Docker]

To solve this problem I have built SecureAuthAPI, here i demonstrated how using Java and SpringBoot Framework to built RESTAPIs quickly as it handles web server, dependency injection, config, security, database connection

• While SpringSecurity handles authentication, authorization, password encryption, security filters. Now instead of storing sessions in server memory
• I have used JWT (JSON Web Token: a token used to authenticate user).
• I have also used Redis(In memory database used for caching, as its faster than mysql and can store user sessions and cached user data).
• Last I have used Docker to package the application into a container.

secureauthapi
│
├── src/main/java/com/example/auth
│
│   ├── controller #handles HTTP requests
│   ├── service #contains business logic like hashing pass, validating login, calling repository
│   ├── repository #handles database operations
│   ├── model #represents database tables
│   ├── security #handles authentication logic like it generates JWT and validate, it also includes security config and Filters
│   ├── config
│   └── middleware #contains filters executed before requests reaches controller as (Requests -> IP Filter -> Rate Limit Filter -> Controller)
│
├── resources
│     application.yml
│
├── pom.xml
└── Dockerfile

User registers
      ↓
Password stored hashed
      ↓
User logs in
      ↓
Server validates password
      ↓
JWT token generated
      ↓
Client stores token
      ↓
Client sends token in header
      ↓
Server verifies JWT
      ↓
Protected APIs allowed

Client (Postman / Frontend)
          ↓
Controller
          ↓
Service
          ↓
Repository
          ↓
Database

Security Layer
   JWT Validation
   Rate Limiting
   IP Filtering

Cache Layer
   Redis

• Double click or run SecureAuthAPI.bat file, just type ./SecureAuthAPI.bat in terminal
• Or type these two cmds, mvn clean install and mvn spring-boot:run

• To build docker container docker build -t secureauthapi .
• To run docker container docker run -p 8080:8080 secureauthapi