efcore-specifications

EF Core Specifications Skill

This skill helps GitHub Copilot generate code using DKNet's EF Core Specifications package (DKNet.EfCore.Specifications) for building reusable, type-safe, and dynamic queries.

🎯 Package Purpose

DKNet.EfCore.Specifications provides:

• Specification Pattern - Encapsulate query logic in reusable classes
• Dynamic Predicates - Build queries from runtime conditions safely
• LinqKit Integration - Compose complex expressions with .And(), .Or()
• Type Safety - Compile-time checking with runtime flexibility

NuGet Package: DKNet.EfCore.Specifications

📦 Installation

dotnet add package DKNet.EfCore.Specifications

🏗️ Core Concepts

1. Specification Pattern

Specifications encapsulate query logic for reusability and testability.

Basic Specification

using DKNet.EfCore.Specifications;

/// <summary>
///     Specification for filtering active products.
/// </summary>
public class ActiveProductsSpec : Specification<Product>
{
    /// <summary>
    ///     Initializes a new instance of the <see cref="ActiveProductsSpec"/> class.
    /// </summary>
    public ActiveProductsSpec()
    {
        // Define filter criteria
        WithFilter(p => !p.IsDeleted && p.IsActive);
        
        // Add ordering
        AddOrderBy(p => p.Name);
    }
}

// Usage
var spec = new ActiveProductsSpec();
var products = await repository.ToListAsync(spec, cancellationToken);

Specification with Parameters

/// <summary>
///     Specification for products by category with optional price filter.
/// </summary>
public class ProductsByCategorySpec : Specification<Product>
{
    /// <summary>
    ///     Initializes a new instance of the <see cref="ProductsByCategorySpec"/> class.
    /// </summary>
    /// <param name="categoryId">The category identifier.</param>
    /// <param name="minPrice">Optional minimum price filter.</param>
    public ProductsByCategorySpec(Guid categoryId, decimal? minPrice = null)
    {
        // Base filter
        var predicate = PredicateBuilder.New<Product>(
            p => !p.IsDeleted && p.CategoryId == categoryId);
        
        // Add optional price filter
        if (minPrice.HasValue)
        {
            predicate = predicate.And(p => p.Price >= minPrice.Value);
        }
        
        WithFilter(predicate);
        
        // Include related entities
        AddInclude(p => p.Category);
        AddInclude(p => p.Reviews);
        
        // Add ordering
        AddOrderBy(p => p.Price);
        AddOrderByDescending(p => p.Rating);
    }
}