PHP routing example

index.php

<?php

$routes = [
    'GET /' => function (string $method, array $params) {
        echo 'Welcome!';
    },
    '(GET|POST) /hello(/(?<name>[^/]++))?' => function (string $method, array $params) {
        \printf('Hello, %s!', $params['name'] ?? 'World');
    },
];

$req = \sprintf('%s %s', $_SERVER['REQUEST_METHOD'], $_SERVER['PATH_INFO'] ?? '/');

$controller = function () {
    \http_response_code(404);
    echo '404 Not Found';
};

$params = [];

foreach ($routes as $route => $_controller) {
    if (\preg_match(\sprintf('#^%s$#', $route), $req, $params)) {
        $controller = $_controller;
        break;
    }
}

$controller($_SERVER['REQUEST_METHOD'], $params);