BooksService API - Clean Architecture Implementation

Overview

This project is a modular and scalable .NET 8 RESTful API built using Clean Architecture principles. It serves as a demo application for managing books, users, roles, and categories. It also includes features like auditing, validation, and scheduled background services.

Technologies Used

• .NET 8
• Entity Framework Core (Code-First + SQLite)
• MediatR
• AutoMapper
• FluentValidation
• xUnit for testing
• Docker

Project Structure (Clean Architecture)

BooksService
├── BooksService.Api             --> Entry point (Controllers, Middleware, Program.cs)
├── BooksService.Application     --> Business logic (Commands, Queries, Validators, Interfaces)
├── BooksService.Domain          --> Domain models and exceptions
├── BooksService.Infrastructure  --> Audit 
├── BooksService.Persistence     --> EF DbContext, Repositories, Decorators, Configuration
└── BooksService.Tests           --> Unit tests (xUnit, Moq)

Features Implemented

Domain

• User, Role, Book, Category entities with relationships
• Business validation methods in domain (e.g. Category.EnsureDeletable())

Application Layer

• CQRS with MediatR (Commands/Handlers)
  • CreateUserCommand
  • UpdateUserRoleCommand
  • DeleteCategoryCommand
• DTOs and AutoMapper Profiles
• FluentValidation for input validation

Persistence Layer

• EF Core DbContext with SQLite
• Repository pattern + generic decorators:
  • AuditAddDecorator<TEntity>
  • AuditUpdateDecorator<TEntity>
  • AuditDeleteDecorator<TEntity>
• Seeding of sample data (Users, Roles, Books, Categories)

API Layer

• Controllers for Users, Books, etc.
• Swagger UI
• Global Exception Middleware
• API Response Models (PagedResponse, ErrorResponse, etc.)

Background Services

• AuditCleanupService: Deletes audit records older than 20 days

Testing

• xUnit used for testing command handlers
• Moq used for mocking dependencies
• Tests included for:
  • CreateUserCommandHandler
  • UpdateUserRoleCommandHandler
  • DeleteCategoryCommandHandler

Audit Logging

• Dedicated AuditLogs table
• Tracks Create, Update, Delete actions via decorators
• Background cleanup service runs daily to delete old logs

Docker

• Dockerfile for the API
• SQLite database stored in the container file system

Getting Started

1. Run the app:

dotnet run --project BooksService.Api

Note

• Dummy data is inserted on DB initialization only if the DB is newly created.
• Decorators are injected using interfaces like IAddRepository<TEntity>, IUpdateRepository<TEntity>, etc.

Summary

This app demonstrates a solid Clean Architecture design with separation of concerns, testability, and scalability. It includes decorators, audit logging, background processing, and custom validation.