Infrastructure, Application, and Domain Layered Architecture

The main goal of this architectural style is to make a clear distinction between the core code of your application and the infrastructure code that supports it.

Code Problem

$ebookPrice = DB::table('ebooks')->where('id',  $request->ebook_id)->value('price');
$orderAmount = (int) $request->quantity * (int) $ebookPrice;
$record = [
  'email' => $request->email_address,
  'quantity' => (int) $request->quantity,
  'amount' => $orderAmount,
];
$lastInsertedId = DB::table('orders')->insertGetId($record);
session(['currentOrderId' => $lastInsertedId]);
return  new Response($lastInsertedId);

The code above would be the basis for refactoring to achieve code that is completely independent of any infrastructure using the Domain, Application and Infrastructure layered architecture

Using Domain, Application and Infrastructure layered architecture

This idea behind this architecture is to separate core code which forms your business logic from infrastructure code that supports the core code. The code code is usually separated into domain and applications layers. The domain layer basically extracts codes from database interaction code into entities and repositories. The Application layer at its core extract services from controllers.

Project Implementation

Implemented with Laravel hence the domain and application layers relies on laravel namespace. But you can reuse them in other frameworks like Symfony, etc. that has a namepace beginning with of App.

Application Directory

This folder contains the codes for various use cases of the application. These are called services. It has a service for creating an ebook, creating ebook order, listing all available ebooks and showing a single ebook

Domain Directory

This contains code that represent entities interacting with the database and their repositories

Repositories Directory

Provides the implementation details of repositories of Domain entities

Infrastructure Directory

Currently, the controllers of Laravel forms my Infrastructure layer. Not that sure if that's the right approach

Sample database structure used here

CREATE DATABASE iad_db;

USE iad_db;

CREATE TABLE `ebooks` (
  `id` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `name` varchar(20) NOT NULL,
  `price` int(11) NOT NULL,
  `discount` int(11) DEFAULT NULL,
  `uuid` varchar(60) NOT NULL
);

CREATE TABLE `orders` (
  `id` int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `email` varchar(30) NOT NULL,
  `amount` int(20) NOT NULL,
  `quantity` int(40) NOT NULL,
  `uuid` varchar(64) NOT NULL
);

Sample Endpoints

POST: http://127.0.0.1:8000/api/ebooks/

POST: http://127.0.0.1:8000/api/ebooks/{REPLACE_WITH_EBOOK_UUID}/order

GET: http://127.0.0.1:8000/api/ebooks/{REPLACE_WITH_EBOOK_UUID}

GET: http://127.0.0.1:8000/api/ebooks/

Current Concerns