DDD in an "onionshell"

Anastasiia Lysenko

13Chats

Scalable Distributed System

Onion Architecture

Domain Layer

"This layer is the heart of business software"

(Eric Evans)

DDD is definitely NOT about technology. DDD is all about the domain.

Application layer

• Is responsible for the navigation between the UI screens in the bounded context as well as the interaction with application layers of other bounded contexts.

• Can perform the basic (non business related) validation on the user input data before transmitting it to the other (lower) layers of the application.

• Should not contain any business or domain related logic, but definitely should perform tasks from the UI requests via services.

Application layer

Infrastructure Layer

• consists Shared libraries for Domain, Application, and UI layer

• communicates with external systems, such as DB or search engine adapters

Presentation Layer

• presenting information to the user and interpreting user commands

• translate incoming requests to method calls for the application layer

•  translate the return values to responses.

Full Picture