RESTful WebAPI With Onion Architecture

Hello friends, here I will show you how to create a WebApi with the following characteristics:

• ASP.Core 2.1
• EntityFramework
• FluentValidation
• Nlogger
• Swagger
• Jwt

Let's start. First create an empty project, then add the following folders:

1. Application
2. Domain
3. Service
4. Infrastructure

Then in the Domain folder, we create a library project Net.Core 2.1 with the name WebApi.Domain add the following dependencies

• FluentValidation.AspNetCore

In this project, we add the following folders:

• Dtos
• Entities
• Interfaces

In the Entities folder, we create the BaseEntity class:

Our project classes will inherit the field Id from this abstract class (if you want you can add other fields like CreatedAt or CreatedBy).

Now to make the exercise more interesting, we are going to assume that we do not want to expose all the Country class. In the Dtos folder, we create the following CountryDensityDTO class.

This class exposes Name, Capital Area, Population and a calculated field Populationdensity.

Now we will continue with the Infrastructure layer and then we will finish the missing parts.

We go to the Infrastructure folder and create a library Net.Core 2.1. We name it WebApi.Infrastructure.Data.

We add the following Packages:

We create the following folders:

• Context
• EntityDbMapping
• Repository

In the Context Folder, we add the SqlServerContext class.

We refer to our Country entity with DbSet to work with the database.

As we work with CodeFirst approach, we will create a mapping for our entity Country in the database.

"modelBuilder.Entity<Country>(new CountryMap().Configure);"