Request Stack

hierarchical.php

<?php

class Request
{
    public $controller;
    public $vars;
    public function __construct(array $vars = array())
    {
        $this->vars = $vars;
    }
    public function get($name, $default = '')
    {
        if (array_key_exists($name, $this->vars)) {
            return $this->vars[$name];
        }
        return $default;
    }
}

class Http
{
    public function handle(Request $request, array $stack = array())
    {
        $stack[] = $request;
        $response = call_user_func($request->controller, $stack);

        return $response;
    }
}

class Controller
{
    protected $http;
    public function __construct(Http $http)
    {
        $this->http = $http;
    }
    protected function handle($action, array $requests)
    {
        $request = new Request();
        $request->controller = array($this, $action);

        $response = $this->http->handle($request, $requests);
        $response .= $this->calledFrom($requests); // Inside the handle should
                                                   // not be last one, but the
                                                   // previous one.

        return $response;
    }
    protected function calledFrom(array $requests)
    {
        return '(' . $this->currentRequest($requests)->controller[1] . ')';
    }
    protected function currentRequest(array $requests)
    {
        return $requests[count($requests) - 1];
    }
}

class Dashboard extends Controller
{
    public function index(array $requests)
    {
        $widgets = $this->handle('widgetHello', $requests)
                 . $this->handle('widgetStats', $requests);

        return 'Widgets{' . $widgets . '}';
    }

    public function widgetHello(array $requests)
    {
        $request = $this->currentRequest($requests);
        $name = $request->get('name', 'World');

        return 'Hello ' . $name;
    }

    public function widgetStats(array $requests)
    {
        $stats = $this->handle('statsVisits', $requests)
               . $this->handle('statsHits', $requests);

        return 'Stats{' . $stats . '}';
    }

    public function statsVisits(array $requests)
    {
        return 'Visits:123';
    }

    public function statsHits(array $requests)
    {
        return 'Hits:321';
    }
}

$http = new Http();
$request = new Request($_GET);
$request->controller = array(new Dashboard($http), 'index');
$response = $http->handle($request);

echo $response . PHP_EOL;