Routes, Routers and Routing in PHP (code to accompany https://youtu.be/JycBuHA-glg)

.htaccess

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^ index.php [QSA,L]

composer.json

{
    "require": {
        "phroute/phroute": "^2.2"
    }
}

index.php

<?php

declare(strict_types=1);

use Phroute\Phroute\RouteCollector;
use Phroute\Phroute\Dispatcher;

$path = parse_url($_SERVER["REQUEST_URI"], PHP_URL_PATH);

require "vendor/autoload.php";

$router = new RouteCollector;

$router->any("/", function() {
    return "This is the homepage";
});

$router->get("/products/{id:\d+}", function($id) {
    return "This is the page for product $id";
});

$dispatcher = new Dispatcher($router->getData());

$response = $dispatcher->dispatch($_SERVER["REQUEST_METHOD"], $path);

echo $response;

/*
require "Router.php";

$router = new Router;

$router->add("/", function() {
    echo "This is the homepage";
});

$router->add("/about", function() {
    echo "This is the about page";
});

$router->add("/products/{id}", function($id) {
    echo "This is the page for product $id";
});

$router->add("/products/{id}/orders/{order_id}", function($id, $order_id) {
    echo "This is the page for product $id, and order $order_id";
});

$router->dispatch($path);
*/

/*
switch ($path) {
    case "/":
        echo "This is the homepage";
        break;
    case "/about":
        echo "This is the about page";
        break;
    case "/contact":
        echo "This is the contact page";
        break;
    default:
        echo "Page not found";
}
*/

Router.php

<?php

declare(strict_types=1);

class Router
{
    private array $routes = [];

    public function add(string $path, Closure $handler): void
    {
        $this->routes[$path] = $handler;
    }

    public function dispatch(string $path): void
    {
        foreach ($this->routes as $route => $handler) {

            $pattern = preg_replace("#\{\w+\}#", "([^\/]+)", $route);

            if (preg_match("#^$pattern$#", $path, $matches)) {

                array_shift($matches);

                call_user_func_array($handler, $matches);

                return;

            }
        }

        echo "Page not found";
    }
}