Implementing Clean Architecture On .NET

In this article, we are going to learn how to implement Clean Architecture on .NET. We are going to create 3 projects: Application Core, Infrastructure, and Web API.

Prerequisites

  • Visual Studio 2019 with .NET 5 SDK
  • SQL Server Database

1. Create Application Core project

Create a blank solution named "StoreCleanArchitecture" and add a solution folder named "src", inside create a Class library project (create the src folder the directory project as well) with .NET Standard 2.1

Implement Clean Architecture On .NET

Create the following folders,

  • DTOs
  • Entities
  • Exceptions
  • Interfaces
  • Mappings
  • Utils

Install AutoMapper.Extensions.Microsoft.DependencyInjection.

Create DependencyInjection class.

using Microsoft.Extensions.DependencyInjection;
using System.Reflection;

namespace Store.ApplicationCore
{
    public static class DependencyInjection
    {
        public static IServiceCollection AddApplicationCore(this IServiceCollection services)
        {
            services.AddAutoMapper(Assembly.GetExecutingAssembly());

            return services;
        }
    }
}

In Entities folder, create Product class.

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace Store.ApplicationCore.Entities
{
    public class Product
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        [MaxLength(30)]
        public string Name { get; set; }

        public string Description { get; set; }
        public int Stock { get; set; }
        public double Price { get; set; }
        public DateTime CreatedAt { get; set; }
        public DateTime UpdatedAt { get; set; }
    }
}

In DTOs folder, create Product class to specify the requests and response.

using System;
using System.ComponentModel.DataAnnotations;

namespace Store.ApplicationCore.DTOs
{
    public class CreateProductRequest
    {
        [Required]
        [StringLength(30, MinimumLength = 3)]
        public string Name { get; set; }

        [Required]
        public string Description { get; set; }

        [Required]
        [Range(0.01, 1000)]
        public double Price { get; set; }
    }

    public class UpdateProductRequest : CreateProductRequest
    {
        [Required]
        [Range(0, 100)]
        public int Stock { get; set; }
    }

    public class ProductResponse
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Description { get; set; }
        public int Stock { get; set; }
        public double Price { get; set; }
    }
}

In Mappings folder, create GeneralProfile class. This is useful to map automatically from the Request to the Entity and from the Entity to the Response.

using AutoMapper;
using Store.ApplicationCore.DTOs;
using Store.ApplicationCore.Entities;

namespace Store.ApplicationCore.Mappings
{
    public class GeneralProfile : Profile
    {
        public GeneralProfile()
        {
            CreateMap<CreateProductRequest, Product>();
            CreateMap<Product, ProductResponse>();
        }
    }
}

In Interfaces folder, create IProductRepository interface. Here we create the methods for the CRUD.

using Store.ApplicationCore.DTOs;
using System.Collections.Generic;

namespace Store.ApplicationCore.Interfaces
{
    public interface IProductRepository
    {
        List<ProductResponse> GetProducts();

        ProductResponse GetProductById(int productId);

        void DeleteProductById(int productId);

        ProductResponse CreateProduct(CreateProductRequest request);

        ProductResponse UpdateProduct(int productId, UpdateProductRequest request);
    }
}

In Exceptions folder, create NotFoundException class.

using System;

namespace Store.ApplicationCore.Exceptions
{
    public class NotFoundException : Exception
    {
    }
}

In Utils folder, create DateUtil class.

using System;

namespace Store.ApplicationCore.Utils
{
    public class DateUtil
    {
        public static DateTime GetCurrentDate()
        {
            return TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, TimeZoneInfo.Local);
        }
    }
}

2. Create Infrastructure project

Create a Class library project with .NET 5, named Store.Infrastructure.

Create Persistence folder, and inside create Contexts and Repositories folders.

Install Microsoft.EntityFrameworkCore.SqlServer.

Right click on Store.Infrastucture project / Add / Project Reference ... / Check Store.ApplicationCore / OK.

Implement Clean Architecture On .NET

In Contexts folder, create StoreContext class. Here we add Product entity to the DbSets in order to communicate with the database to the Products table.

using Microsoft.EntityFrameworkCore;
using Store.ApplicationCore.Entities;

namespace Store.Infrastructure.Persistence.Contexts
{
    public class StoreContext : DbContext
    {
        public StoreContext(DbContextOptions<StoreContext> options) : base(options)
        {
        }

        public DbSet<Product> Products { get; set; }
    }
}

In Repositories folder, create ProductRepository class.

using AutoMapper;
using Store.ApplicationCore.DTOs;
using Store.ApplicationCore.Entities;
using Store.ApplicationCore.Exceptions;
using Store.ApplicationCore.Interfaces;
using Store.ApplicationCore.Utils;
using Store.Infrastructure.Persistence.Contexts;
using System.Collections.Generic;
using System.Linq;

namespace Store.Infrastructure.Persistence.Repositories
{
    public class ProductRepository : IProductRepository
    {
        private readonly StoreContext storeContext;
        private readonly IMapper mapper;

        public ProductRepository(StoreContext storeContext, IMapper mapper)
        {
            this.storeContext = storeContext;
            this.mapper = mapper;
        }

        public ProductResponse CreateProduct(CreateProductRequest request)
        {
            var product = this.mapper.Map<Product>(request);
            product.Stock = 0;
            product.CreatedAt = product.UpdatedAt = DateUtil.GetCurrentDate();

            this.storeContext.Products.Add(product);
            this.storeContext.SaveChanges();

            return this.mapper.Map<ProductResponse>(product);
        }

        public void DeleteProductById(int productId)
        {
            var product = this.storeContext.Products.Find(productId);
            if (product != null)
            {
                this.storeContext.Products.Remove(product);
                this.storeContext.SaveChanges();
            }
            else
            {
                throw new NotFoundException();
            }
        }

        public ProductResponse GetProductById(int productId)
        {
            var product = this.storeContext.Products.Find(productId);
            if (product != null)
            {
                return this.mapper.Map<ProductResponse>(product);
            }

            throw new NotFoundException();
        }

        public List<ProductResponse> GetProducts()
        {
            return this.storeContext.Products.Select(p => this.mapper.Map<ProductResponse>(p)).ToList();
        }

        public ProductResponse UpdateProduct(int productId, UpdateProductRequest request)
        {
            var product = this.storeContext.Products.Find(productId);
            if (product != null)
            {
                product.Name = request.Name;
                product.Description = request.Description;
                product.Price = request.Price;
                product.Stock = request.Stock;
                product.UpdatedAt = DateUtil.GetCurrentDate();

                this.storeContext.Products.Update(product);
                this.storeContext.SaveChanges();

                return this.mapper.Map<ProductResponse>(product);
            }

            throw new NotFoundException();
        }
    }
}

Create DependencyInjection class, add the following:

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Store.ApplicationCore.Interfaces;
using Store.Infrastructure.Persistence.Contexts;
using Store.Infrastructure.Persistence.Repositories;

namespace Store.Infrastructure
{
    public static class DependencyInjection
    {
        public static IServiceCollection AddInfrastructure(this IServiceCollection services, IConfiguration configuration)
        {
            var defaultConnectionString = configuration.GetConnectionString("DefaultConnection");
            services.AddDbContext<StoreContext>(options =>
               options.UseSqlServer(defaultConnectionString));

            services.AddScoped<IProductRepository, ProductRepository>();

            return services;
        }
    }
}

There we are configuring the db context and adding IProductRepository to the services collection as Scoped.

3. Create Web API project

Create a "Web API project" with .NET 5, named Store.WebApi.

Implement Clean Architecture On .NET

Right click on Store.WebApi / Set as Startup project.

At the top, click on Debug / Start Without Debugging.

Implement Clean Architecture on dotNET

Remove WeatherForecast and WeatherForecastController files.

Add the references to the Store.ApplicationCore and Store.Infrastructure projects.

Add the connection string to SQL Server in appsettings.json.

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "DefaultConnection": "Server=localhost;Database=DemoStore;Trusted_Connection=True;"
  }
}

In Startup class, in ConfigureServices method add the extensions for Application Core and Infrastructure.

...
using Store.ApplicationCore;
using Store.Infrastructure;
...

public void ConfigureServices(IServiceCollection services)
        {
            services.AddApplicationCore();
            services.AddInfrastructure(Configuration);
            services.AddControllers();
            services.AddSwaggerGen(c =>
            {
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "Store.WebApi", Version = "v1" });
            });
        }

Open Package Manager Console and select Store.Infrastructure project as default. Execute Add-Migration InitialCreate -Context StoreContext.

Implement Clean Architecture On .NET

In Store.Infrastructure project, a Migrations folder with 2 files inside were created.

Then, from the Package Manager Console, execute Update-Database. From Controllers, add a controller named ProductsController.

Implement Clean Architecture On .NET

using Microsoft.AspNetCore.Mvc;
using Store.ApplicationCore.DTOs;
using Store.ApplicationCore.Exceptions;
using Store.ApplicationCore.Interfaces;
using System.Collections.Generic;

namespace Store.WebApi.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class ProductsController : Controller
    {
        private readonly IProductRepository productRepository;

        public ProductsController(IProductRepository productRepository)
        {
            this.productRepository = productRepository;
        }

        [HttpGet]
        public ActionResult<List<ProductResponse>> GetProducts()
        {
            return Ok(this.productRepository.GetProducts());
        }

        [HttpGet("{id}")]
        public ActionResult GetProductById(int id)
        {
            try
            {
                var product = this.productRepository.GetProductById(id);
                return Ok(product);
            }
            catch (NotFoundException)
            {
                return NotFound();
            }
        }

        [HttpPost]
        public ActionResult Create(CreateProductRequest request)
        {
            var product = this.productRepository.CreateProduct(request);
            return Ok(product);
        }

        [HttpPut("{id}")]
        public ActionResult Update(int id, UpdateProductRequest request)
        {
            try
            {
                var product = this.productRepository.UpdateProduct(id, request);
                return Ok(product);
            }
            catch (NotFoundException)
            {
                return NotFound();
            }
        }

        [HttpDelete("{id}")]
        public ActionResult Delete(int id)
        {
            try
            {
                this.productRepository.DeleteProductById(id);
                return NoContent();
            }
            catch (NotFoundException)
            {
                return NotFound();
            }
        }
    }
}

Now, you can test the API.

Implement Clean Architecture on dotNET

You can find the source code here.

Thanks for reading

Thank you very much for reading, I hope you found this article interesting and may be useful in the future. If you have any questions or ideas that you need to discuss, it will be a pleasure to be able to collaborate and exchange knowledge together.


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