PHP Attributes: Modern Metadata in Your Code

use Attribute;

#[Attribute]
class Route {
    public function __construct(
        public string $path,
        Since PHP 8, we’ve had attributes — a modern way to add metadata directly to classes, methods, or properties. Think of them like annotations in Java or decorators in Python.






  
  
  🔖 What are attributes?


Attributes let you “tag” parts of your code with extra information. Frameworks or libraries can then read these tags at runtime and act on them.

Example:




#[Route('/home', methods: ['GET'])]
class HomeController {
    // ...
}


Here, the Route attribute describes how this controller should be exposed.

  ⚙️ How do you define an attribute?


Attributes are just classes marked with #[Attribute].


use Attribute;

#[Attribute]
class Route {
    public function __construct(
        public string $path,
        public array $methods = ['GET']
    ) {}
}



  🔍 How to read attributes with Reflection


You can fetch and use attributes at runtime via the Reflection API:


$reflection = new ReflectionClass(HomeController::class);

// Get all attributes on the class
foreach ($reflection->getAttributes(Route::class) as $attr) {
    // Turn attribute into a real object
    $route = $attr->newInstance();

    echo $route->path;     // "/home"
    echo implode(',', $route->methods); // "GET"
}


This is how frameworks like Symfony or Doctrine process metadata and apply logic automatically.

  ✅ Why use attributes?



Cleaner than PHPDoc comments
More flexible than marker interfaces
Supported natively by PHP, no hacks needed


  🏛️ Where are they used?




Symfony → #[Route] for controllers

Doctrine ORM → #[Entity], #[Column] for database mapping
Custom apps → logging, caching, validation rules

🔑 In short: Attributes bring structured, modern metadata to PHP. They’re concise, powerful, and built right into the language — and with reflection, they let your code adapt based on annotations.