DDDAdvisor 1.0.4

🧠 DDDAdvisor - Roslyn Analyzer

Your personal Domain-Driven Design mentor, right inside your IDE.

DDDAdvisor is a Roslyn analyzer that provides real-time feedback and DDD best practice tips directly in your IDE as you code. Get instant warnings, suggestions, and guidance to help you build better domain models following DDD principles.

✨ What Does It Do?

DDDAdvisor analyzes your C# code in real-time and provides actionable feedback on:

• Anemic Entities - Detects entities with no domain behavior (only properties)
• Mutable Value Objects - Finds value objects that violate immutability
• Layer Violations - Catches domain depending on infrastructure (DIP violations)
• Direct Repository Access - Identifies controllers accessing repositories directly
• Entity Exposure - Warns when domain entities are exposed from API endpoints
• Large Application Services - Detects services with too many responsibilities

🚀 Installation

NuGet Package Manager

Install-Package DDDAdvisor

.NET CLI

dotnet add package DDDAdvisor

Package Reference

<PackageReference Include="DDDAdvisor" Version="1.0.3" />

That's it! Build your solution and you'll immediately see DDD tips in your IDE.

📖 How It Works

Once installed, DDDAdvisor automatically analyzes your code. Warnings and suggestions appear directly in your IDE (Visual Studio, Visual Studio Code, Rider, etc.).

Example 1: Anemic Entity Detection

❌ Before (Triggers Warning):

// ⚠️ DDD001: Entity 'Customer' contains no domain behavior
public class Customer
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int LoyaltyPoints { get; set; }
}

✅ After (Fixed):

public class Customer
{
    public int Id { get; private set; }
    public string Name { get; private set; }
    public int LoyaltyPoints { get; private set; }

    // Domain behavior added
    public void AddLoyaltyPoints(int points)
    {
        if (points < 0)
            throw new ArgumentException("Points cannot be negative");

        LoyaltyPoints += points;
    }

    public void UpdateName(string newName)
    {
        if (string.IsNullOrWhiteSpace(newName))
            throw new ArgumentException("Name cannot be empty");

        Name = newName;
    }
}

Example 2: Mutable Value Object

❌ Before (Triggers Warning):

// ⚠️ DDD002: Value object 'Money' should be immutable
public class Money
{
    public decimal Amount { get; set; }
    public string Currency { get; set; }
}

✅ After (Fixed):

public class Money
{
    public decimal Amount { get; private set; }
    public string Currency { get; private set; }

    public Money(decimal amount, string currency)
    {
        Amount = amount;
        Currency = currency;
    }

    public Money Add(Money other)
    {
        if (Currency != other.Currency)
            throw new InvalidOperationException("Cannot add money with different currencies");

        return new Money(Amount + other.Amount, Currency);
    }
}

Example 3: Direct Repository Access in Controller

❌ Before (Triggers Error):

// ✗ DDD201: Direct repository access in controller 'OrdersController'
public class OrdersController : ControllerBase
{
    private readonly IOrderRepository _orderRepository;

    public OrdersController(IOrderRepository orderRepository)
    {
        _orderRepository = orderRepository;
    }

    [HttpGet("{id}")]
    public IActionResult Get(int id)
    {
        var order = _orderRepository.GetById(id);
        return Ok(order);
    }
}

✅ After (Fixed):

public class OrdersController : ControllerBase
{
    private readonly IOrderService _orderService;

    public OrdersController(IOrderService orderService)
    {
        _orderService = orderService;
    }

    [HttpGet("{id}")]
    public IActionResult Get(int id)
    {
        var orderDto = _orderService.GetOrderById(id);
        return Ok(orderDto);
    }
}

🎯 Complete Rule Reference

⚙️ Configuration

Create a dddadvisor.json file in your solution root to customize analyzer behavior:

{
  "rules": {
    "AnemicEntity": true,
    "MutableValueObject": true,
    "LayerDependencies": true,
    "DirectRepositoryAccess": true,
    "EntityExposedFromApi": true,
    "LargeApplicationService": true
  },
  "severityOverrides": {
    "DDD001": "Warning",
    "DDD002": "Warning",
    "DDD101": "Error",
    "DDD201": "Error"
  },
  "layerMappings": {
    "Domain": ".*Domain.*",
    "Application": ".*Application.*",
    "Infrastructure": ".*Infrastructure.*",
    "Presentation": ".*API.*|.*Web.*|.*Controllers.*"
  },
  "excludePaths": ["**/obj/**", "**/bin/**", "**/Migrations/**"]
}

Configuration Options

• rules: Enable/disable specific rules
• severityOverrides: Change severity levels (Error, Warning, Info, Hidden)
• layerMappings: Define regex patterns to identify your architectural layers
• excludePaths: Glob patterns for paths to exclude from analysis

Suppressing Warnings

You can suppress warnings using standard .NET attributes:

[System.Diagnostics.CodeAnalysis.SuppressMessage("DDD", "DDD001:Anemic Entity")]
public class Customer
{
    public string Name { get; set; }
}

Or use #pragma directives:

#pragma warning disable DDD001
public class Customer
{
    public string Name { get; set; }
}
#pragma warning restore DDD001

🔧 IDE Integration

Visual Studio

Warnings appear in:

• Error List window
• Code editor (green squiggles for suggestions, yellow for warnings)
• Quick Actions lightbulb (Ctrl+.)

Visual Studio Code

Install the C# extension, and warnings appear in:

• Problems panel
• Code editor with squiggles
• Code Actions lightbulb

JetBrains Rider

Warnings appear in:

• Problems window
• Code editor with highlights
• Alt+Enter quick fixes menu