FN.FileManagement

A .NET 10 solution demonstrating N-tier architecture with SOLID principles, applied to file upload and management. Built as a reference implementation covering all layers from REST API down to data access.

Architecture

The solution is structured in strict one-way dependency order:

Presentation     FN.WebApi  ·  FN.Web  ·  FN.WinForm
                      |
Application          FN.Application
                      |
Business Logic       FN.Business
                      |
Data Access          FN.DataLayer
                      |
Cross-cutting    FN.Entities  ·  FN.Common  ·  FN.Functions

Each layer depends only on layers below it. FN.Entities, FN.Common, and FN.Functions can be referenced from any layer.

Projects

Project	Responsibility
FN.WebApi	REST API (ASP.NET Core, Swagger/OpenAPI)
FN.Web	Web UI (ASP.NET Core + Angular client app)
FN.WinForm	Windows Forms desktop client
FN.Application	Use-case services and validators (IUploadService, UploadService, UploadModelValidator)
FN.Business	Domain services and business rules (IUploadDataService, UploadDataService)
FN.DataLayer	EF Core 10 repositories and DbContext (IUploadRepository, UploadRepository)
FN.Entities	DTOs and domain models (UploadModel, UploadedModel)
FN.Common	Shared utilities, FluentValidation extensions
FN.Functions	File helpers — upload/download handlers, content-type detection, image resizing (ImageSharp)

Technology Stack

• .NET 10 / ASP.NET Core
• Entity Framework Core 10 — in-memory database (toggled via appsettings.json)
• FluentValidation 12 — input validation
• SixLabors.ImageSharp — image processing
• Swagger / OpenAPI — API documentation
• Newtonsoft.Json — JSON serialization

API Endpoints

Uploads — /api/uploads

Method	Route	Description
GET	/api/uploads	List all uploads
GET	/api/uploads/{id}	Get upload by ID
GET	/api/uploads/{id}/{fileName}	View upload details
GET	/api/uploads/download/{id}	Download file
POST	/api/uploads	Upload a new file (multipart/form-data)
DELETE	/api/uploads/{id}	Delete an upload

Getting Started

Prerequisites: .NET 10 SDK, Visual Studio 2022+ or VS Code.

# Restore dependencies
dotnet restore

# Run the REST API
cd FN.WebApi
dotnet run
# API available at https://localhost:5001

# Run the Web UI
cd FN.Web
dotnet run

# Run the desktop client (Windows only)
cd FN.WinForm
dotnet run

Configuration (appsettings.json)

Key	Description
UseInMemoryDatabase	true for in-memory DB (default), false for persistent
UploadPath	Directory where uploaded files are stored

Layer Dependency Rules

• Presentation depends on Application
• Application depends on Business
• Business depends on DataLayer
• Entities, Common, Functions are shared — any layer may reference them
• No upward dependencies

Adding a New Domain

1. Define DTOs in FN.Entities
2. Add repository interface in FN.DataLayer/Abstractions
3. Implement repository in FN.DataLayer/Repositories
4. Add data service in FN.Business/Services (business rules here)
5. Add application service in FN.Application/Services (orchestration + validation)
6. Register all services in FN.WebApi/Configuration/ServiceCollectionExtensions.cs
7. Add controller in FN.WebApi/Controllers