Implementing a Real-World Feature Across Drupal, Symfony, and Laravel

Feature: E-Commerce “Discount Code Validator”

Requirement:

• When a user applies a discount code during checkout:
  • Validate the code
  • Check expiration and usage limits
  • Calculate discount
  • Return an updated order total
• Must be extensible for future promotion types

This feature is small but touches services, events, plugins, and DI—perfect for comparing modular approaches.

Dependency Injection Without Pain: Symfony, Laravel, and Drupal Explained

Introduction

Dependency Injection (DI) is a cornerstone of modern PHP frameworks, but many developers—especially those coming from Drupal—find it confusing. Why inject services instead of calling them directly? How do DI containers differ between Drupal, Symfony, and Laravel?

In this article, we’ll break it down with practical examples, showing how to use DI without headaches across these three systems.

1. What is Dependency Injection?

Simply put:

Universal “Soldier” in PHP

Templating: Twig vs Blade

After controllers, DI, and Request handling, the next key layer is view rendering.
In PHP frameworks, this usually means templating engines:

• Symfony/Drupal: Twig
• Laravel: Blade

Even though the syntax differs, the concept is the same: the controller prepares data, passes it to a template, and the template renders HTML.

Universal “Soldier” in PHP

Dependency Injection Without Pain (Symfony, Laravel, Drupal)

In the first article, we covered the controller as a universal entry point into any modern PHP framework.
Now it’s time for the next critical step — Dependency Injection (DI).

Many developers fear DI because:

• “There’s too much magic”
• “I don’t understand where objects come from”
• “In Drupal it’s a nightmare”

The good news is simple:

The Universal “Soldier” in PHP

How to Tame Any Framework. Step One — The Controller

The PHP ecosystem is fragmented: Symfony, Laravel, Drupal, Yii, Slim…
At first glance, each framework feels like a separate universe with its own rules, magic, and “correct” way of doing things.

But there is good news:

90% of modern PHP frameworks speak the same language.
That language is HTTP and Symfony Components.