Onion Architecture In ASP NET Core 6 Web API

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For this article, Let’s have a WebApi that has just one entity, Product. We will perform CRUD Operations on it while using the Onion architecture. To maintain structural Sanity in Mid to Larger Solutions, it is always recommended to follow some kind of architecture. You must have seen most of the Open Sourced Projects having multiple layers of Projects within a complex folder structure. With n FKs, I would need n queries, plus the computational overhead to piece everything together the way I want the DTO to look like.

But I really believe that the idea could be used in the MVC apps as well. Maybe that presentation part would be a slight issue, maybe not, as I said I didn’t use it. You didn’t insult anyone, you’ve just shared your opinion and question. EF Core is now a pretty good tool (well to be more precise it is a great tool and it is like that for a while now), it is fast – with every new version even faster. But I understand that developers like to write their own SQL queries, and I have nothing against that, whatsoever I support that idea a lot. Just, we have been doing a lot of work with EF Core and it proved to be a great tool for us, so we are using it mostly in our articles and our books.

In this project we will setup Entity Framework Core which will access the CRUD operations performed by CQRS. Recall, we already created CRUD operations on the Application project. You can also add the Entity Framework Core package by running the command Install-Package Microsoft.EntityFrameworkCore on the Package Manager Console window of Visual Studio. Remember to select the Application project from the “Default project” dropdown.

Going back to the diagram, if you did read my previous articles you will be familiar with The Dependency Rule. It is the most important thing when building a Clean Architecture onion architecture .net core and summarizing this rule says that the concentric circles represent different areas of software. In general, the further in you go, the higher level the software becomes.

  1. In a real world application you’d probably want the project to be part of a NuGet package that it can be used where needed.
  2. Thank you for the comment and your suggestions, I am pretty sure our readers will benefit from them.
  3. Domain is the innermost layer while Infrastructure + Presentation is outermost layer.
  4. Let us take a look at what are the advantages of Onion architecture, and why we would want to implement it in our projects.

In the Onion Architecture there are separatable concentric layers of codes such that the inner most layer is fully independent to other layers. Mostly you have 3 layers in this architecture and these are – Domain, Application and “Infrastructure + Presentation”. Domain is the innermost layer while Infrastructure + Presentation is outermost layer. We will do a simple test to ensure that our solution works.

Presentation Layer:

Good coding, clean approach and splitting of responsibilities. If you refer to ForCreation and ForUpdate DTOs, then those are validated with the attributes because we use them inside the request in our actions. Could you help me understand the choice behind adding validation logic to some of the DTOs in the Contracts solution?

First, you need to create the Asp.net Core web API project using visual studio. The main problem returning of IQueryable is that UnitTesting no longer will be working. Because the query which is send to database is no longer controllable with IQueryable. Query code can be contained in Repository, or Service layer, or Controller.

The flow of dependencies dictates what a certain layer in the Onion architecture can do. Because it depends on the layers below it in the hierarchy, it can only call the methods that are exposed by the lower layers. We are depending on abstractions at compile-time, which gives us strict contracts to work with, and we are being provided with the implementation at runtime.

What is Onion architecture?

In your ebook “Ultimate ASP.Net Core Web API”, did you use Onion Architecture or Layered architecture ? And why you choose that architecture in that project. Just modify the access level of the OwnerService if it is internal in your app. I will read the articles you proposed, for better enlightment. I use most of Map() methods within Controllers’ actions. Instead of in memory, I will be using a database – Adventureworks 2017.

Abstract Factory Method Design Pattern

Now we need to add the student controller that will interact will our service layer and display the data to the users. Now in the ICustomServices folder, we will create the ICustomServices Interface, this interface holds the signature of the method. We will implement these methods in the customs service code of the ICustomServices Interface given below. For the Domain layer, we need to add the library project to our application. What do you mean by Calculable properties, I’m not sure that I understand? Basically, any business logic should be moved to the service layer, so yes, calculations go there as well.

Now create a Class Library project inside the Infrastructure folder. We will be calling the method AddApplication from the Program class when we will create the Presentation layer. Start by adding the MediatR NuGet package to the Application project. The Infrastructure and Presentation Layers are outermost layers of Onion Architecture.

But of course, you don’t want to keep it in the Repository as there you hardly want to map something, you want to work with entities. So, you can have it either in the main project or in the service. If you use mappings in both the main project and the service layer, then having it in the main projects is a better option. Supermarket.Http.Utilities is named differently from the other projects. Its classes aren’t domain specific and are generic enough that they can be used in many different contexts. In a real world application you’d probably want the project to be part of a NuGet package that it can be used where needed.

Let’s Implement Onion Architecture in ASP.NET Core with CQRS

The purpose of the Presentation layer is to represent the entry point to our system so that consumers can interact with the data. We can implement this layer in many ways, for example creating a REST API, gRPC, etc. Notice that we are setting the CancellationToken argument as an optional value, and giving it the default value.

It holds all the logic related to the Business requirements. Now, every application ideally has its own dedicated Database. In order to access the Database, we introduce a Data Access Layer. This layer usually holds ORMs for ASP.NET to fetch/write to the database. In this https://1investing.in/ article, We will talk about Onion Architecture In ASP.NET Core and its advantages. We will also together build a WebApi that follows a variant of Onion Architecture so that we get to see why it is important to implement such an architecture in your upcoming projects.

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