S.O.L.I.D Principles - A Real World Guide

Intro Writing maintainable, scalable, and clean code is essential for any developer. The SOLID principles help achieve this by enforcing good design patterns. In this guide, we'll refactor parts of a real-world application to follow SOLID principles. S - Singles Responsibility Principle (SRP) each class should have only one reason to change. ❌ Bad Example: Service Doing too much

Feb 21, 2025 - 20:38

S.O.L.I.D Principles - A Real World Guide

Intro

Writing maintainable, scalable, and clean code is essential for any developer. The SOLID principles help achieve this by enforcing good design patterns.
In this guide, we'll refactor parts of a real-world application to follow SOLID principles.

S - Singles Responsibility Principle (SRP)

each class should have only one reason to change.

❌ Bad Example: Service Doing too much



class OrderService {
    public function processOrder($order) {
        // Process order logic
        echo "Order processed!";

        // Sends email confirmation (SRP violation)
        mail($order->customer_email, "Your order is confirmed!", "Details...");

        // Logs action (SRP violation)
        file_put_contents("logs.txt", "Order processed: " . $order->id);
    }
}