Router

<?php

class Router {
    protected $path;
    protected $defaultHandler;
    protected $routes = array();

    public function __construct($path = null, $default_handler = null, array $routes = null) {
        $this->setPath($path);
        $this->setDefaultHandler($default_handler);
        if (is_array($routes)) {
            $this->setRoutes($routes);
        }
    }

    public function setPath($path) {
        $this->path = $path;
    }

    public function setDefaultHandler($handler) {
        $this->defaultHandler = $handler;
    }

    public function setRoutes(array $routes) {
        foreach ($routes as $pattern => $handler) {
            $this->setRoute($pattern, $handler);
        }
    }

    public function setRoute($route, $handler) {
        preg_match('!^(?:(\w+)\s*)?(/\S*)$!', trim($route), $matches);
        if (empty($matches)) {
            throw new Exception('Bad route');
        }
        list($method, $pattern) = array_slice($matches, 1);
        $method = $method ? strtoupper($method) : '*';
        $placeholders = array(
            'id' => '[1-9]\d{0,9}',
            'int' => '\d+',
            'str' => '\w+',
        );
        foreach ($placeholders as $k => $v) {
            $pattern = str_replace("<$k>", "($v)", $pattern);
        }
        $pattern = "#^$pattern\$#";
        $this->routes[$method][$pattern] = $handler;
    }

    public function run() {
        foreach ($this->routes as $method => $patterns) {
            if ($method == '*' || $method == $_SERVER['REQUEST_METHOD']) {
                foreach ($patterns as $pattern => $handler) {
                    if (preg_match($pattern, $this->path, $matches)) {
                        return $this->invoke($handler, array_slice($matches, 1));
                    }
                }
            }
        }
        if ($this->defaultHandler) {
            $this->invoke($this->defaultHandler);
        }
    }

    protected function invoke($handler, $args = array()) {
        $arr = preg_split('/\s*\.\s*/', trim($handler), 2);
        $arr[0] = new $arr[0];
        $arr[1] = isset($arr[1]) && $arr[1] ? $arr[1] : 'index';
        call_user_func_array($arr, $args);
    }
}