Dotnet Backend Patterns

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development

Patrones de desarrollo backend en C#/.NET para APIs robustas, servidores MCP y aplicaciones empresariales. Cubre async/await, DI, EF Core, Dapper, cach├® y testing.

ID: dotnet-backend-patterns

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---

name: dotnet-backend-patterns

description: Master C#/.NET backend development patterns for building robust APIs, MCP servers, and enterprise applications. Covers async/await, dependency injection, Entity Framework Core, Dapper, configuration, caching, and testing with xUnit. Use when developing .NET backends, reviewing C# code, or designing API architectures.

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.NET Backend Development Patterns

Master C#/.NET patterns for building production-grade APIs, MCP servers, and enterprise backends with modern best practices (2024/2025).

When to Use This Skill

Developing new .NET Web APIs or MCP servers
Reviewing C# code for quality and performance
Designing service architectures with dependency injection
Implementing caching strategies with Redis
Writing unit and integration tests
Optimizing database access with EF Core or Dapper
Configuring applications with IOptions pattern
Handling errors and implementing resilience patterns

Core Concepts

1. Project Structure (Clean Architecture)


src/
??? Domain/                     # Core business logic (no dependencies)
?   ??? Entities/
?   ??? Interfaces/
?   ??? Exceptions/
?   ??? ValueObjects/
??? Application/                # Use cases, DTOs, validation
?   ??? Services/
?   ??? DTOs/
?   ??? Validators/
?   ??? Interfaces/
??? Infrastructure/             # External implementations
?   ??? Data/                   # EF Core, Dapper repositories
?   ??? Caching/                # Redis, Memory cache
?   ??? External/               # HTTP clients, third-party APIs
?   ??? DependencyInjection/    # Service registration
??? Api/                        # Entry point
    ??? Controllers/            # Or MinimalAPI endpoints
    ??? Middleware/
    ??? Filters/
    ??? Program.cs




2. Dependency Injection Patterns

`csharp


// Service registration by lifetime
public static class ServiceCollectionExtensions
{
    public static IServiceCollection AddApplicationServices(
        this IServiceCollection services,
        IConfiguration configuration)
    {
        // Scoped: One instance per HTTP request
        services.AddScoped<IProductService, ProductService>();
        services.AddScoped<IOrderService, OrderService>();


        // Singleton: One instance for app lifetime
        services.AddSingleton<ICacheService, RedisCacheService>();
        services.AddSingleton<IConnectionMultiplexer>(_ =>
            ConnectionMultiplexer.Connect(configuration["Redis:Connection"]!));


        // Transient: New instance every time
        services.AddTransient<IValidator<CreateOrderRequest>, CreateOrderValidator>();


        // Options pattern for configuration
        services.Configure<CatalogOptions>(configuration.GetSection("Catalog"));
        services.Configure<RedisOptions>(configuration.GetSection("Redis"));


        // Factory pattern for conditional creation
        services.AddScoped<IPriceCalculator>(sp =>
        {
            var options = sp.GetRequiredService<IOptions<PricingOptions>>().Value;
            return options.UseNewEngine
                ? sp.GetRequiredService<NewPriceCalculator>()
                : sp.GetRequiredService<LegacyPriceCalculator>();
        });


        // Keyed services (.NET 8+)
        services.AddKeyedScoped<IPaymentProcessor, StripeProcessor>("stripe");
        services.AddKeyedScoped<IPaymentProcessor, PayPalProcessor>("paypal");


        return services;
    }
}


// Usage with keyed services
public class CheckoutService
{
    public CheckoutService(
        [FromKeyedServices("stripe")] IPaymentProcessor stripeProcessor)
    {
        _processor = stripeProcessor;
    }
}




3. Async/Await Patterns

`csharp


// ? CORRECT: Async all the way down
public async Task<Product> GetProductAsync(string id, CancellationToken ct = default)
{
    return await _repository.GetByIdAsync(id, ct);
}


// ? CORRECT: Parallel execution with WhenAll
public async Task<(Stock, Price)> GetStockAndPriceAsync(
    string productId, 
    CancellationToken ct = default)
{
    var stockTask = _stockService.GetAsync(productId, ct);
    var priceTask = _priceService.GetAsync(productId, ct);


    await Task.WhenAll(stockTask, priceTask);


    return (await stockTask, await priceTask);
}


// ? CORRECT: ConfigureAwait in libraries
public async Task<T> LibraryMethodAsync<T>(CancellationToken ct = default)
{
    var result = await _httpClient.GetAsync(url, ct).ConfigureAwait(false);
    return await result.Content.ReadFromJsonAsync<T>(ct).ConfigureAwait(false);
}


// ? CORRECT: ValueTask for hot paths with caching
public ValueTask<Product?> GetCachedProductAsync(string id)
{
    if (_cache.TryGetValue(id, out Product? product))
        return ValueTask.FromResult(product);


    return new ValueTask<Product?>(GetFromDatabaseAsync(id));
}


// ? WRONG: Blocking on async (deadlock risk)
var result = GetProductAsync(id).Result;  // NEVER do this
var result2 = GetProductAsync(id).GetAwaiter().GetResult(); // Also bad


// ? WRONG: async void (except event handlers)
public async void ProcessOrder() { }  // Exceptions are lost


// ? WRONG: Unnecessary Task.Run for already async code
await Task.Run(async () => await GetDataAsync());  // Wastes thread




4. Configuration with IOptions

`csharp


// Configuration classes
public class CatalogOptions
{
    public const string SectionName = "Catalog";


    public int DefaultPageSize { get; set; } = 50;
    public int MaxPageSize { get; set; } = 200;
    public TimeSpan CacheDuration { get; set; } = TimeSpan.FromMinutes(15);
    public bool EnableEnrichment { get; set; } = true;
}


public class RedisOptions
{
    public const string SectionName = "Redis";


    public string Connection { get; set; } = "localhost:6379";
    public string KeyPrefix { get; set; } = "mcp:";
    public int Database { get; set; } = 0;
}


// appsettings.json
{
    "Catalog": {
        "DefaultPageSize": 50,
        "MaxPageSize": 200,
        "CacheDuration": "00:15:00",
        "EnableEnrichment": true
    },
    "Redis": {
        "Connection": "localhost:6379",
        "KeyPrefix": "mcp:",
        "Database": 0
    }
}


// Registration
services.Configure<CatalogOptions>(configuration.GetSection(CatalogOptions.SectionName));
services.Configure<RedisOptions>(configuration.GetSection(RedisOptions.SectionName));


// Usage with IOptions (singleton, read once at startup)
public class CatalogService
{
    private readonly CatalogOptions _options;


    public CatalogService(IOptions<CatalogOptions> options)
    {
        _options = options.Value;
    }
}


// Usage with IOptionsSnapshot (scoped, re-reads on each request)
public class DynamicService
{
    private readonly CatalogOptions _options;


    public DynamicService(IOptionsSnapshot<CatalogOptions> options)
    {
        _options = options.Value;  // Fresh value per request
    }
}


// Usage with IOptionsMonitor (singleton, notified on changes)
public class MonitoredService
{
    private CatalogOptions _options;


    public MonitoredService(IOptionsMonitor<CatalogOptions> monitor)
    {
        _options = monitor.CurrentValue;
        monitor.OnChange(newOptions => _options = newOptions);
    }
}




5. Result Pattern (Avoiding Exceptions for Flow Control)

`csharp


// Generic Result type
public class Result<T>
{
    public bool IsSuccess { get; }
    public T? Value { get; }
    public string? Error { get; }
    public string? ErrorCode { get; }


    private Result(bool isSuccess, T? value, string? error, string? errorCode)
    {
        IsSuccess = isSuccess;
        Value = value;
        Error = error;
        ErrorCode = errorCode;
    }


    public static Result<T> Success(T value) => new(true, value, null, null);
    public static Result<T> Failure(string error, string? code = null) => new(false, default, error, code);


    public Result<TNew> Map<TNew>(Func<T, TNew> mapper) =>
        IsSuccess ? Result<TNew>.Success(mapper(Value!)) : Result<TNew>.Failure(Error!, ErrorCode);


    public async Task<Result<TNew>> MapAsync<TNew>(Func<T, Task<TNew>> mapper) =>
        IsSuccess ? Result<TNew>.Success(await mapper(Value!)) : Result<TNew>.Failure(Error!, ErrorCode);
}


// Usage in service
public async Task<Result<Order>> CreateOrderAsync(CreateOrderRequest request, CancellationToken ct)
{
    // Validation
    var validation = await _validator.ValidateAsync(request, ct);
    if (!validation.IsValid)
        return Result<Order>.Failure(
            validation.Errors.First().ErrorMessage, 
            "VALIDATION_ERROR");


    // Business rule check
    var stock = await _stockService.CheckAsync(request.ProductId, request.Quantity, ct);
    if (!stock.IsAvailable)
        return Result<Order>.Failure(
            $"Insufficient stock: {stock.Available} available, {request.Quantity} requested",
            "INSUFFICIENT_STOCK");


    // Create order
    var order = await _repository.CreateAsync(request.ToEntity(), ct);


    return Result<Order>.Success(order);
}


// Usage in controller/endpoint
app.MapPost("/orders", async (
    CreateOrderRequest request,
    IOrderService orderService,
    CancellationToken ct) =>
{
    var result = await orderService.CreateOrderAsync(request, ct);


    return result.IsSuccess
        ? Results.Created($"/orders/{result.Value!.Id}", result.Value)
        : Results.BadRequest(new { error = result.Error, code = result.ErrorCode });
});




Data Access Patterns


Entity Framework Core

`csharp


// DbContext configuration
public class AppDbContext : DbContext
{
    public DbSet<Product> Products => Set<Product>();
    public DbSet<Order> Orders => Set<Order>();


    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        // Apply all configurations from assembly
        modelBuilder.ApplyConfigurationsFromAssembly(typeof(AppDbContext).Assembly);


        // Global query filters
        modelBuilder.Entity<Product>().HasQueryFilter(p => !p.IsDeleted);
    }
}


// Entity configuration
public class ProductConfiguration : IEntityTypeConfiguration<Product>
{
    public void Configure(EntityTypeBuilder<Product> builder)
    {
        builder.ToTable("Products");


        builder.HasKey(p => p.Id);
        builder.Property(p => p.Id).HasMaxLength(40);
        builder.Property(p => p.Name).HasMaxLength(200).IsRequired();
        builder.Property(p => p.Price).HasPrecision(18, 2);


        builder.HasIndex(p => p.Sku).IsUnique();
        builder.HasIndex(p => new { p.CategoryId, p.Name });


        builder.HasMany(p => p.OrderItems)
            .WithOne(oi => oi.Product)
            .HasForeignKey(oi => oi.ProductId);
    }
}


// Repository with EF Core
public class ProductRepository : IProductRepository
{
    private readonly AppDbContext _context;


    public async Task<Product?> GetByIdAsync(string id, CancellationToken ct = default)
    {
        return await _context.Products
            .AsNoTracking()
            .FirstOrDefaultAsync(p => p.Id == id, ct);
    }


    public async Task<IReadOnlyList<Product>> SearchAsync(
        ProductSearchCriteria criteria,
        CancellationToken ct = default)
    {
        var query = _context.Products.AsNoTracking();


        if (!string.IsNullOrWhiteSpace(criteria.SearchTerm))
            query = query.Where(p => EF.Functions.Like(p.Name, $"%{criteria.SearchTerm}%"));


        if (criteria.CategoryId.HasValue)
            query = query.Where(p => p.CategoryId == criteria.CategoryId);


        if (criteria.MinPrice.HasValue)
            query = query.Where(p => p.Price >= criteria.MinPrice);


        if (criteria.MaxPrice.HasValue)
            query = query.Where(p => p.Price <= criteria.MaxPrice);


        return await query
            .OrderBy(p => p.Name)
            .Skip((criteria.Page - 1) * criteria.PageSize)
            .Take(criteria.PageSize)
            .ToListAsync(ct);
    }
}




Dapper for Performance

`csharp


public class DapperProductRepository : IProductRepository
{
    private readonly IDbConnection _connection;


    public async Task<Product?> GetByIdAsync(string id, CancellationToken ct = default)
    {
        const string sql = """
            SELECT Id, Name, Sku, Price, CategoryId, Stock, CreatedAt
            FROM Products
            WHERE Id = @Id AND IsDeleted = 0
            """;


        return await _connection.QueryFirstOrDefaultAsync<Product>(
            new CommandDefinition(sql, new { Id = id }, cancellationToken: ct));
    }


    public async Task<IReadOnlyList<Product>> SearchAsync(
        ProductSearchCriteria criteria,
        CancellationToken ct = default)
    {
        var sql = new StringBuilder("""
            SELECT Id, Name, Sku, Price, CategoryId, Stock, CreatedAt
            FROM Products
            WHERE IsDeleted = 0
            """);


        var parameters = new DynamicParameters();


        if (!string.IsNullOrWhiteSpace(criteria.SearchTerm))
        {
            sql.Append(" AND Name LIKE @SearchTerm");
            parameters.Add("SearchTerm", $"%{criteria.SearchTerm}%");
        }


        if (criteria.CategoryId.HasValue)
        {
            sql.Append(" AND CategoryId = @CategoryId");
            parameters.Add("CategoryId", criteria.CategoryId);
        }


        if (criteria.MinPrice.HasValue)
        {
            sql.Append(" AND Price >= @MinPrice");
            parameters.Add("MinPrice", criteria.MinPrice);
        }


        if (criteria.MaxPrice.HasValue)
        {
            sql.Append(" AND Price <= @MaxPrice");
            parameters.Add("MaxPrice", criteria.MaxPrice);
        }


        sql.Append(" ORDER BY Name OFFSET @Offset ROWS FETCH NEXT @PageSize ROWS ONLY");
        parameters.Add("Offset", (criteria.Page - 1) * criteria.PageSize);
        parameters.Add("PageSize", criteria.PageSize);


        var results = await _connection.QueryAsync<Product>(
            new CommandDefinition(sql.ToString(), parameters, cancellationToken: ct));


        return results.ToList();
    }


    // Multi-mapping for related data
    public async Task<Order?> GetOrderWithItemsAsync(int orderId, CancellationToken ct = default)
    {
        const string sql = """
            SELECT o.*, oi.*, p.*
            FROM Orders o
            LEFT JOIN OrderItems oi ON o.Id = oi.OrderId
            LEFT JOIN Products p ON oi.ProductId = p.Id
            WHERE o.Id = @OrderId
            """;


        var orderDictionary = new Dictionary<int, Order>();


        await _connection.QueryAsync<Order, OrderItem, Product, Order>(
            new CommandDefinition(sql, new { OrderId = orderId }, cancellationToken: ct),
            (order, item, product) =>
            {
                if (!orderDictionary.TryGetValue(order.Id, out var existingOrder))
                {
                    existingOrder = order;
                    existingOrder.Items = new List<OrderItem>();
                    orderDictionary.Add(order.Id, existingOrder);
                }


                if (item != null)
                {
                    item.Product = product;
                    existingOrder.Items.Add(item);
                }


                return existingOrder;
            },
            splitOn: "Id,Id");


        return orderDictionary.Values.FirstOrDefault();
    }
}




Caching Patterns


Multi-Level Cache with Redis

`csharp


public class CachedProductService : IProductService
{
    private readonly IProductRepository _repository;
    private readonly IMemoryCache _memoryCache;
    private readonly IDistributedCache _distributedCache;
    private readonly ILogger<CachedProductService> _logger;


    private static readonly TimeSpan MemoryCacheDuration = TimeSpan.FromMinutes(1);
    private static readonly TimeSpan DistributedCacheDuration = TimeSpan.FromMinutes(15);


    public async Task<Product?> GetByIdAsync(string id, CancellationToken ct = default)
    {
        var cacheKey = $"product:{id}";


        // L1: Memory cache (in-process, fastest)
        if (_memoryCache.TryGetValue(cacheKey, out Product? cached))
        {
            _logger.LogDebug("L1 cache hit for {CacheKey}", cacheKey);
            return cached;
        }


        // L2: Distributed cache (Redis)
        var distributed = await _distributedCache.GetStringAsync(cacheKey, ct);
        if (distributed != null)
        {
            _logger.LogDebug("L2 cache hit for {CacheKey}", cacheKey);
            var product = JsonSerializer.Deserialize<Product>(distributed);


            // Populate L1
            _memoryCache.Set(cacheKey, product, MemoryCacheDuration);
            return product;
        }


        // L3: Database
        _logger.LogDebug("Cache miss for {CacheKey}, fetching from database", cacheKey);
        var fromDb = await _repository.GetByIdAsync(id, ct);


        if (fromDb != null)
        {
            var serialized = JsonSerializer.Serialize(fromDb);


            // Populate both caches
            await _distributedCache.SetStringAsync(
                cacheKey,
                serialized,
                new DistributedCacheEntryOptions
                {
                    AbsoluteExpirationRelativeToNow = DistributedCacheDuration
                },
                ct);


            _memoryCache.Set(cacheKey, fromDb, MemoryCacheDuration);
        }


        return fromDb;
    }


    public async Task InvalidateAsync(string id, CancellationToken ct = default)
    {
        var cacheKey = $"product:{id}";


        _memoryCache.Remove(cacheKey);
        await _distributedCache.RemoveAsync(cacheKey, ct);


        _logger.LogInformation("Invalidated cache for {CacheKey}", cacheKey);
    }
}


// Stale-while-revalidate pattern
public class StaleWhileRevalidateCache<T>
{
    private readonly IDistributedCache _cache;
    private readonly TimeSpan _freshDuration;
    private readonly TimeSpan _staleDuration;


    public async Task<T?> GetOrCreateAsync(
        string key,
        Func<CancellationToken, Task<T>> factory,
        CancellationToken ct = default)
    {
        var cached = await _cache.GetStringAsync(key, ct);


        if (cached != null)
        {
            var entry = JsonSerializer.Deserialize<CacheEntry<T>>(cached)!;


            if (entry.IsStale && !entry.IsExpired)
            {
                // Return stale data immediately, refresh in background
                _ = Task.Run(async () =>
                {
                    var fresh = await factory(CancellationToken.None);
                    await SetAsync(key, fresh, CancellationToken.None);
                });
            }


            if (!entry.IsExpired)
                return entry.Value;
        }


        // Cache miss or expired
        var value = await factory(ct);
        await SetAsync(key, value, ct);
        return value;
    }


    private record CacheEntry<TValue>(TValue Value, DateTime CreatedAt)
    {
        public bool IsStale => DateTime.UtcNow - CreatedAt > _freshDuration;
        public bool IsExpired => DateTime.UtcNow - CreatedAt > _staleDuration;
    }
}




Testing Patterns


Unit Tests with xUnit and Moq

`csharp


public class OrderServiceTests
{
    private readonly Mock<IOrderRepository> _mockRepository;
    private readonly Mock<IStockService> _mockStockService;
    private readonly Mock<IValidator<CreateOrderRequest>> _mockValidator;
    private readonly OrderService _sut; // System Under Test


    public OrderServiceTests()
    {
        _mockRepository = new Mock<IOrderRepository>();
        _mockStockService = new Mock<IStockService>();
        _mockValidator = new Mock<IValidator<CreateOrderRequest>>();


        // Default: validation passes
        _mockValidator
            .Setup(v => v.ValidateAsync(It.IsAny<CreateOrderRequest>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new ValidationResult());


        _sut = new OrderService(
            _mockRepository.Object,
            _mockStockService.Object,
            _mockValidator.Object);
    }


    [Fact]
    public async Task CreateOrderAsync_WithValidRequest_ReturnsSuccess()
    {
        // Arrange
        var request = new CreateOrderRequest
        {
            ProductId = "PROD-001",
            Quantity = 5,
            CustomerOrderCode = "ORD-2024-001"
        };


        _mockStockService
            .Setup(s => s.CheckAsync("PROD-001", 5, It.IsAny<CancellationToken>()))
            .ReturnsAsync(new StockResult { IsAvailable = true, Available = 10 });


        _mockRepository
            .Setup(r => r.CreateAsync(It.IsAny<Order>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new Order { Id = 1, CustomerOrderCode = "ORD-2024-001" });


        // Act
        var result = await _sut.CreateOrderAsync(request);


        // Assert
        Assert.True(result.IsSuccess);
        Assert.NotNull(result.Value);
        Assert.Equal(1, result.Value.Id);


        _mockRepository.Verify(
            r => r.CreateAsync(It.Is<Order>(o => o.CustomerOrderCode == "ORD-2024-001"), 
            It.IsAny<CancellationToken>()), 
            Times.Once);
    }


    [Fact]
    public async Task CreateOrderAsync_WithInsufficientStock_ReturnsFailure()
    {
        // Arrange
        var request = new CreateOrderRequest { ProductId = "PROD-001", Quantity = 100 };


        _mockStockService
            .Setup(s => s.CheckAsync(It.IsAny<string>(), It.IsAny<int>(), It.IsAny<CancellationToken>()))
            .ReturnsAsync(new StockResult { IsAvailable = false, Available = 5 });


        // Act
        var result = await _sut.CreateOrderAsync(request);


        // Assert
        Assert.False(result.IsSuccess);
        Assert.Equal("INSUFFICIENT_STOCK", result.ErrorCode);
        Assert.Contains("5 available", result.Error);


        _mockRepository.Verify(
            r => r.CreateAsync(It.IsAny<Order>(), It.IsAny<CancellationToken>()), 
            Times.Never);
    }


    [Theory]
    [InlineData(0)]
    [InlineData(-1)]
    [InlineData(-100)]
    public async Task CreateOrderAsync_WithInvalidQuantity_ReturnsValidationError(int quantity)
    {
        // Arrange
        var request = new CreateOrderRequest { ProductId = "PROD-001", Quantity = quantity };


        _mockValidator
            .Setup(v => v.ValidateAsync(request, It.IsAny<CancellationToken>()))
            .ReturnsAsync(new ValidationResult(new[]
            {
                new ValidationFailure("Quantity", "Quantity must be greater than 0")
            }));


        // Act
        var result = await _sut.CreateOrderAsync(request);


        // Assert
        Assert.False(result.IsSuccess);
        Assert.Equal("VALIDATION_ERROR", result.ErrorCode);
    }
}




Integration Tests with WebApplicationFactory

`csharp


public class ProductsApiTests : IClassFixture<WebApplicationFactory<Program>>
{
    private readonly WebApplicationFactory<Program> _factory;
    private readonly HttpClient _client;


    public ProductsApiTests(WebApplicationFactory<Program> factory)
    {
        _factory = factory.WithWebHostBuilder(builder =>
        {
            builder.ConfigureServices(services =>
            {
                // Replace real database with in-memory
                services.RemoveAll<DbContextOptions<AppDbContext>>();
                services.AddDbContext<AppDbContext>(options =>
                    options.UseInMemoryDatabase("TestDb"));


                // Replace Redis with memory cache
                services.RemoveAll<IDistributedCache>();
                services.AddDistributedMemoryCache();
            });
        });


        _client = _factory.CreateClient();
    }


    [Fact]
    public async Task GetProduct_WithValidId_ReturnsProduct()
    {
        // Arrange
        using var scope = _factory.Services.CreateScope();
        var context = scope.ServiceProvider.GetRequiredService<AppDbContext>();


        context.Products.Add(new Product
        {
            Id = "TEST-001",
            Name = "Test Product",
            Price = 99.99m
        });
        await context.SaveChangesAsync();


        // Act
        var response = await _client.GetAsync("/api/products/TEST-001");


        // Assert
        response.EnsureSuccessStatusCode();
        var product = await response.Content.ReadFromJsonAsync<Product>();
        Assert.Equal("Test Product", product!.Name);
    }


    [Fact]
    public async Task GetProduct_WithInvalidId_Returns404()
    {
        // Act
        var response = await _client.GetAsync("/api/products/NONEXISTENT");


        // Assert
        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
    }
}




Best Practices


DO
1. Use async/await all the way through the call stack
2. Inject dependencies through constructor injection
3. Use IOptions<T> for typed configuration
4. Return Result types instead of throwing exceptions for business logic
5. Use CancellationToken in all async methods
6. Prefer Dapper for read-heavy, performance-critical queries
7. Use EF Core for complex domain models with change tracking
8. Cache aggressively with proper invalidation strategies
9. Write unit tests for business logic, integration tests for APIs
10. Use record types for DTOs and immutable data


DON'T

1. Don't block on async with .Result or .Wait()


2. Don't use async void except for event handlers
3. Don't catch generic Exception without re-throwing or logging
4. Don't hardcode configuration values
5. Don't expose EF entities directly in APIs (use DTOs)

6. Don't forget AsNoTracking() for read-only queries


7. Don't ignore CancellationToken parameters

8. Don't create new HttpClient() manually (use IHttpClientFactory)


9. Don't mix sync and async code unnecessarily
10. Don't skip validation at API boundaries


Common Pitfalls

N+1 Queries: Use .Include() or explicit joins

Memory Leaks: Dispose IDisposable resources, use using`
Deadlocks: Don't mix sync and async, use ConfigureAwait(false) in libraries
Over-fetching: Select only needed columns, use projections
Missing Indexes: Check query plans, add indexes for common filters
Timeout Issues: Configure appropriate timeouts for HTTP clients
Cache Stampede: Use distributed locks for cache population

Resources

assets/service-template.cs: Complete service implementation template
assets/repository-template.cs: Repository pattern implementation
references/ef-core-best-practices.md: EF Core optimization guide
references/dapper-patterns.md: Advanced Dapper usage patterns

Informacion

Estado	Activo
Origen	custom
Usos	3
Ultimo uso	23/01 16:57
Actualizado	09/01/2026 00:10

Archivo origen

Z:\Repositorios\platform\docs\.ai\skills\dotnet-backend-patterns\SKILL.md