Attributes

<?php
#[Attribute]
class Route
{
    public function __construct(public string $path, public string $method = "GET") {}
}

class BlogController
{
    #[Route("/blog", method: "GET")]
    public function list(): string
    {
        return "all posts";
    }

    #[Route("/blog/new", method: "POST")]
    public function create(): string
    {
        return "created";
    }
}

$class = new ReflectionClass(BlogController::class);

foreach ($class->getMethods() as $method) {
    foreach ($method->getAttributes(Route::class) as $attribute) {
        $route = $attribute->newInstance();
        echo $route->method . " " . $route->path . " -> " . $method->getName() . "\n";
    }
}

GET /blog -> list
POST /blog/new -> create

#[Route("/blog")]                    // one attribute with an argument
#[Route("/blog"), Cache(60)]         // several, separated by commas
#[Attribute(Attribute::TARGET_METHOD)]   // limits where an attribute may be used

<?php
#[Attribute(Attribute::TARGET_PROPERTY)]
class Required {}

class Form
{
    #[Required]
    public string $name = "";

    public string $note = "";
}

$props = (new ReflectionClass(Form::class))->getProperties();

foreach ($props as $prop) {
    $required = count($prop->getAttributes(Required::class)) > 0;
    echo $prop->getName() . ": " . ($required ? "required" : "optional") . "\n";
}

name: required
note: optional

<?php
function login(string $user, #[\SensitiveParameter] string $password): void
{
    // if an exception happens here, the password is not printed in the stack trace
}