Code Organization

Name: code-organization
Rating: 76
Author: mkspwr12

Purpose: Structure projects for maintainability, scalability, and team collaboration.

When to Use This Skill

•Setting up a new project structure
•Refactoring monolithic codebases
•Implementing dependency injection
•Organizing modules for team collaboration
•Choosing between architectural patterns

Prerequisites

•Understanding of SOLID principles
•Familiarity with project target language

Decision Tree

code

Structuring a project?
├─ New project?
│   ├─ Single app? → Standard layered structure (API/Domain/Infra)
│   ├─ Multiple services? → Monorepo or separate repos
│   └─ Library/package? → src/ + tests/ + docs/ + examples/
├─ Existing project, adding feature?
│   ├─ Follow existing patterns (consistency > perfection)
│   └─ Feature cuts across layers? → Consider vertical slices
├─ File getting too large (> 300 lines)?
│   └─ Split by responsibility (SRP)
├─ Folder getting too deep (> 4 levels)?
│   └─ Flatten or reorganize by feature
└─ Shared code between projects?
    └─ Extract to shared library / internal package

Project Structure

C# (.NET Solution)

code

Solution/
├── src/
│   ├── MyProject.Api/                      # Web API project
│   │   ├── Controllers/
│   │   │   ├── UsersController.cs
│   │   │   ├── ProductsController.cs
│   │   │   └── OrdersController.cs
│   │   ├── Middleware/
│   │   │   ├── AuthenticationMiddleware.cs
│   │   │   ├── LoggingMiddleware.cs
│   │   │   └── RateLimitingMiddleware.cs
│   │   ├── Filters/
│   │   │   ├── ValidationFilter.cs
│   │   │   └── ExceptionFilter.cs
│   │   ├── Program.cs
│   │   ├── Startup.cs                      # or configure in Program.cs
│   │   ├── appsettings.json
│   │   └── appsettings.Development.json
│   ├── MyProject.Core/                     # Domain/Business logic
│   │   ├── Entities/
│   │   │   ├── User.cs
│   │   │   ├── Product.cs
│   │   │   └── Order.cs
│   │   ├── Interfaces/
│   │   │   ├── IUserRepository.cs
│   │   │   ├── IEmailService.cs
│   │   │   └── IPaymentService.cs
│   │   ├── Services/
│   │   │   ├── UserService.cs
│   │   │   ├── PaymentService.cs
│   │   │   └── EmailService.cs
│   │   ├── DTOs/
│   │   │   ├── UserDto.cs
│   │   │   └── ProductDto.cs
│   │   └── Exceptions/
│   │       ├── UserNotFoundException.cs
│   │       └── DuplicateEmailException.cs
│   ├── MyProject.Infrastructure/           # Data access & external services
│   │   ├── Data/
│   │   │   ├── ApplicationDbContext.cs
│   │   │   └── Migrations/
│   │   ├── Repositories/
│   │   │   ├── UserRepository.cs
│   │   │   └── OrderRepository.cs
│   │   └── Services/
│   │       ├── EmailService.cs
│   │       └── BlobStorageService.cs
│   └── MyProject.Shared/                   # Shared utilities
│       ├── Constants/
│       │   └── AppConstants.cs
│       ├── Helpers/
│       │   └── StringHelper.cs
│       └── Validators/
│           └── EmailValidator.cs
├── tests/
│   ├── MyProject.UnitTests/
│   ├── MyProject.IntegrationTests/
│   └── MyProject.E2ETests/
├── docs/
├── scripts/
├── .gitignore
├── MyProject.sln
└── README.md

Best Practices

1. Single Responsibility Principle

csharp

// ❌ Bad: Class does too much
public class User
{
    public void SaveToDatabase() { }
    public void SendEmail() { }
    public void GenerateReport() { }
}

// ✅ Good: Separate concerns
public class User
{
    // Just data and behavior
    public int Id { get; set; }
    public string Email { get; set; }
    public string Name { get; set; }
}

public class UserRepository
{
    public async Task SaveAsync(User user) { }
}

public class EmailService
{
    public async Task SendToUserAsync(User user, string message) { }
}

public class ReportGenerator
{
    public async Task GenerateUserReportAsync(User user) { }
}

2. Keep Files Small

•Max 300-400 lines per file
•Split large files into smaller classes
•Group related functionality

3. Clear Naming

csharp

// ✅ Good naming conventions
// Files: PascalCase.cs
// Classes: PascalCase
// Interfaces: IPascalCase
// Methods: PascalCase
// Variables/parameters: camelCase
// Constants: PascalCase or UPPER_SNAKE_CASE

// UserService.cs
public class UserService
{
    private const int MaxLoginAttempts = 3;
    
    public async Task<bool> AuthenticateUserAsync(string email, string password)
    {
        // Implementation
    }
}

4. Use Namespaces Properly

csharp

// Organize by feature or layer
namespace MyProject.Core.Services
{
    public class UserService { }
}

namespace MyProject.Core.Entities
{
    public class User { }
}

namespace MyProject.Infrastructure.Repositories
{
    public class UserRepository { }
}

namespace MyProject.Api.Controllers
{
    public class UsersController { }
}

Related Skills:

•Core Principles
•Scalability

Troubleshooting

Issue	Solution
Circular dependencies	Extract shared interfaces into a separate abstractions project
Growing monolith	Identify bounded contexts and extract vertical slices
DI container performance	Register scoped/transient services only when needed, prefer singleton for stateless

References

•Code Org Patterns