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Blog Application Technical Documentation

Architecture Overview​

The application follows a layered architecture:

Controller -> Service -> DAO -> Repository -> Database
DTOs <-> Entities (via Mappers)

Design Patterns Implemented​

1. DTO (Data Transfer Object)​

  • Separate DTOs for data input/output
  • Nested Response classes (e.g., CategoryDTO.CategoryResponse)
  • Examples: PostDTO, UserDTO, CategoryDTO

2. DAO (Data Access Object)​

  • Abstracts data persistence operations
  • Transactional management at DAO level
  • Examples: PostDAO, UserDAO, CategoryDAO

3. Mapper Pattern​

  • Handles entity-DTO conversions
  • Maintains separation between domain and presentation layers
  • Examples: PostMapper, UserMapper, CategoryMapper

4. Repository Pattern​

  • Spring Data JPA repositories
  • Extends JpaRepository for CRUD operations
  • Examples: PostRepository, UserRepository, CategoryRepository

5. Service Layer Pattern​

  • Business logic encapsulation
  • Transaction management
  • Coordination between DAOs

Technical Specifications​

1. Framework & Core Technologies​

- Spring Boot: 3.3.5
- Java: 17
- Database: PostgreSQL
- ORM: Hibernate/JPA
- Build System: Maven/Gradle

2. Database Design​

Relational Schema with relationships:

  • Posts -> Authors (Many-to-One)
  • Posts -> Categories (Many-to-One)
  • Comments -> Posts (Many-to-One)
  • Authors -> Users (One-to-One)
  • Posts - Tags (Many-to-Many)

3. Key Features​

  • User Authentication/Management
  • Blog Post CRUD Operations
  • Category Management
  • Comment System
  • Tag System
  • Author Profiles

4. Data Handling​

- JSON Support for Social Media Links
- Slug Generation for Posts
- Timestamp Tracking (created_at, updated_at)
- Status Management for Posts

5. Environment Configuration​

- Profile-based configuration (prod/dev)
- Environment Variable Support
- Doppler Integration for Secrets Management

Security Considerations​

1. Password Handling​

- Hashed Password Storage
- Spring Security Crypto Integration

2. Data Validation​

- Jakarta Validation (@NotBlank, @Email, etc.)
- Custom Validation in Services

Transaction Management​

@Transactional at Service and DAO levels
- Read-only optimization for queries
- Write operations explicitly marked

API Design​

1. RESTful Endpoints​

/api/posts
/api/users
/api/categories
/api/comments
/api/authors
/api/tags

2. Response Format​

{
  "id": "long",
  "data": "specific to entity",
  "timestamps": "audit information"
}

Code Organization​

com.example.dtymcbackend
├── config/
├── controller/
├── dao/
├── dto/
├── mapper/
├── model/
├── repository/
└── service/

Best Practices Implemented​

  1. Separation of Concerns
  2. Immutable DTOs
  3. Proper Exception Handling
  4. Audit Trails
  5. Relationship Management
  6. Environment-specific Configurations

API Examples​

Create a Post​

curl --location 'http://localhost:8080/api/posts' \
--header 'Content-Type: application/json' \
--data '{
    "title": "Sample Post",
    "content": "Content...",
    "status": "DRAFT",
    "authorId": 1,
    "categoryId": 1
}'

Create a Category​

curl --location 'http://localhost:8080/api/categories' \
--header 'Content-Type: application/json' \
--data '{
    "name": "Technology",
    "slug": "technology",
    "description": "Tech related posts"
}'

Error Handling​

  • Standard HTTP status codes
  • Detailed error messages
  • Global exception handling
  • Database constraint violations handling

Future Improvements​

  1. Implement caching
  2. Add API documentation (Swagger/OpenAPI)
  3. Enhance security features
  4. Implement rate limiting
  5. Add monitoring and logging