ByteClass API

ByteClass is a modular, feature-based Spring Boot application for managing e-learning courses, users, and interactive tasks. It showcases simple, but robust architecture, resilience, security, caching, and comprehensive testing.

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📦 Main Features

• User Module (/api/user & /api/auth/login)

  • Register users (name, email, password)
  • Update, delete, list users
  • JWT-based authentication

• Course Module (/api/course)

  • Create, list, retrieve, update, delete courses
  • Publish courses (requires at least one task of each type and continuous order)

• Task Module (/api/task)

  • Create three task types for courses in BUILDING status:

    • Open-text
    • Single-choice (exactly one correct option)
    • Multiple-choice (at least two correct options)

  • List tasks by course, retrieve task details

  • Automatic reordering when inserting a task at an existing position

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📐 Architecture

• Feature-Based Project is organized by feature (user, course, task), each containing its own controllers, services, repositories, DTOs, and mappers.

• Clean Layers

  • Controller: REST endpoints with validation, caching, security
  • Application (Service / Strategy / Facade): business logic, transactions, resilience
  • Repository: Spring Data JPA interfaces
  • Port (DTOs / Mappers): MapStruct for entity ↔ DTO mapping

• Module Decoupling Features interact via interfaces (UserPort, CoursePort, TaskPort), exchanging only DTOs and primitive IDs—no direct entity coupling.

• Resilience Resilience4j integration (@Resilient + AOP) for rate limiting and circuit breaking.

• Security Spring Security OAuth2 Resource Server with JWT; role hierarchy ADMIN > INSTRUCTOR > STUDENT.

• Caching Redis configured and used in controllers via @Cacheable / @CacheEvict.

• Database Migrations Flyway scripts for MySQL schema (V1__… through V4__…_create_table_*.sql).

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📁 Project Structure

src/
├── main/
│   ├── java/…/byteclass/
│   │   ├── ByteClassApplication.java
│   │   ├── common/            # exceptions, handlers, utilities
│   │   ├── config/            # resilience, security, OpenAPI
│   │   └── feature/
│   │       ├── user/          # adapter/controller, service, domain, port
│   │       ├── course/        # adapter/controller, service, facade, domain, port
│   │       └── task/          # adapter/controller, service, strategies, domain, port
│   └── resources/
│       ├── db/migration/      # Flyway scripts
│       ├── application-*.properties
│       ├── app.key / app.pub
│       └── …
└── test/
    ├── java/…/byteclass/feature/
    │   ├── user/…             # UserControllerTest, UserServiceImplTest, etc.
    │   ├── course/…           # CourseControllerTest, CourseServiceImplTest, facade tests
    │   └── task/…             # TaskControllerTest, TaskServiceImplTest, strategy tests
    └── resources/
        └── application-test.properties (H2 in-memory)

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🛠️ Technology Stack

• Language & Framework: Java 21, Spring Boot 3
• Persistence: Spring Data JPA (MySQL)
• Migrations: Flyway
• Security: Spring Security (OAuth2 Resource Server + JWT)
• Resilience: Resilience4j (rate limiter, circuit breaker)
• Mapping & Annotations: Lombok, MapStruct
• Caching: Spring Data Redis
• API Docs: Springdoc OpenAPI (Swagger UI)
• Build & Orchestration: Maven, Docker Compose(MySQL and Redis containers)
• Testing: JUnit 5, Mockito, AssertJ

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🚀 Getting Started

1. Prerequisites

   • Docker & Docker Compose
   • Java 21+
   • 3306 and 6369 ports free

2. Generate RSA Keys

   ./generate_keys.sh

3. Start Infrastructure

   docker-compose up -d

4. Build & Run

   ./mvnw clean package
   ./mvnw spring-boot:run

Or simply run in your preferred IDE

5. Access

   • API Base: http://localhost:8080/api
   • Swagger UI: http://localhost:8080/swagger-ui.html

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🧪 Testing

• Unit Tests: JUnit 5 + Mockito + AssertJ
• Coverage: Services, Controllers, Strategies, Facades, Repositories
• Test Profile: application-test.properties uses H2 in-memory database

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Some references

• Dan Vega: Package by Layer vs Package by Feature