Domain-Driven Design in PHP

Applying Hexagonal Architecture

Continuing with the blog example application, the first concept we need is a Port where the outside world can talk to the application. For this case, we'll use an HTTP Port and its corresponding Adapter. The outside will use the Port to send messages to the application. The blog example was using a database to store the whole collection of blog posts, so in order to allow the application to retrieve blog posts from the database, a Port is needed:

interface PostRepository{    public function byId(PostId $id);    public function add(Post $post);}

This interface exposes the Port that the application will retrieve information about blog posts through, and it'll be located in the Domain Layer. Now an Adapter for this ...