But eventually, this problem was practically eliminated. Based on the DDD model, we’ve created onion architecture (aka hexagonal or clean architecture). Bounded context is a good fit for a microservices architecture. It is much easier to build a microservice around a bounded context. Switchable UI Layer (Presentation) – Since we are keeping all the crucial logic away from the presentation layer, it is quite easy to switch to another tech – including Blazor. Database Independent – Since we have a clean separation of data access, it is quite easy to switch between different database providers.
- Remember that we have two abstract exception classes BadRequestException and NotFoundException inside of the Domain layer?
- So, the only place in your application that actually creates objects that are capable of doing IO is the application’s entrypoint.
- Since this is a very basic controller that calls the mediator object, I will not go in deep.
- All layers also need to provide information that is conveniently consumed by inner layers.
- When doing software development, one of the most important things to have in mind is that your software should always be evolving.
And finally, we saw how our Presentation layer is implemented as a separate project by decoupling the controllers from the main Web application. Then, we explained how we can connect all of the layers using an ASP.NET Core Web API. There are more examples, but hopefully, you get the idea.
It’s easier to maintain an application that has a good separation of concerns. CodeGuru covers topics related to Microsoft-related software development, mobile development, database management, and web application programming. Cloud services such as Microsoft Azure and database options including SQL Server and MSSQL are also frequently covered.
Also, the code is easier to test due to dependency injection, which also contributes to making the software more maintainable. So, the only place in your application that actually creates objects that are capable of doing IO is the application’s entrypoint. The Infrastructure Layer uses them, but is does not create them. In Onion Architecture, the database is just a infrastructure detail. The rest of your code shouldn’t worry if you are storing your data in a database, in a file, or just in memory.
Key Difference between Onion and Clean Architecture
However, we are going to do something different from what you are normally used to when creating Web APIs. By convention, the controllers are defined in the Controllers folder inside of the Web application. Because ASP.NET Core uses Dependency Injection everywhere, we need to have a reference to all of the projects in the solution from the Web application project. This allows us to configure our services inside of the Startup class. Using this approach, we can encapsulate all of the rich business logic in the Domain and Service layers without ever having to know any implementation details. In the Service layer, we are going to depend only on the interfaces that are defined by the layer below, which is the Domain layer.
Any small change in the Business Logics layer or Data access layer may prove dangerous to the integrity of the entire application. 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. Now we can see when we hit the GetAllStudent Endpoint we can see the data of students from the database in the form of JSON projects. We will follow the same project as we did for the Domain layer. Add the library project in your application and give a name to that project Repository layer.
Why Onion Architecture?
Firstly, add a connection string to the appsettings.json found in the WebApi Project. Now add a Product Class that inherits the Id from the BaseEntity. Create a new class Entities/Product.cs in the Domain Project. Next, we http://hit-live.info/index.php_section=games_2.html will need to add the XML File (For Swagger Documentation). To do this, right-click the WebApi Project and go to properties. In the Build Tab enable the XML Documentation file and give an appropriate file name and location.
We first need to calculate the price including tax computation/discounts, etc., save order items and send order confirmation notification to the customer. The application services can be only invoked by Infrastructure services. In this article, we have implemented the Onion architecture using the Entity Framework and Code First approach. We have now the knowledge of how the layer communicates with each other’s in onion architecture and how we can write the Generic code for the Interface repository and services. Now we can develop our project using onion architecture for API Development OR MVC Core Based projects.
Hence, when you separate these requests, you can use different technologies for handler implementation (Dapper, Entity Framework). The practice has shown that 90 percent of requests concern get operations; as a rule, they are small and quick. 10 percent of requests concern put operations; these operations are usually complicated due to a range of transactions and validations. To put it simply, every action in Web API is either a request (get data) or a command (put data), but it shouldn’t do both. Consequently, each API method is divided into requests and commands. The main issues we faced were related to maintaining the low connectivity of microservices.
The Domain project will hold the Domain layer implementation. The Services and Services.Abstractions are going to be our Service layer implementation. The Persistence project will be our Infrastructure layer, and the Presentation project will be the Presentation layer implementation.