Creating an object-oriented router class in PHP

Question

On my way to learn OOP, I am developing a little CMS using the MVC pattern. I would like to have some feedback about my router class, mostly about if I am correctly using OOP.

Right now, I have a .htaccess file redirecting requests to an index.php file, both of them in the root directory of the project.

.htaccess

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !\.(jpg|jpeg|gif|png|css|js|pl|txt|otf|ttf|eot|woff|woff2|svg)$
RewriteRule ^(.*)$ index.php?uri=1ドル [QSA]
</IfModule>

Then I run this router class to get the requested URL and call to the correct controller class and method:

Router.php

<?php
namespace Core;
use Controller;
if ( !class_exists( 'Router' ) ) {
 class Router {
 /**
 * Allowed URL patterns
 * @var Array
 */
 private $routes;
 /**
 * Allowed prefixs for URLs
 * @var String
 */
 private $prefix;
 /**
 * Requested URL
 * @var String
 */
 private $url;
 /**
 * Run the router
 */
 public function run() {
 $this->set_url();
 $this->dispatch();
 }
 /**
 * Set a new route
 */
 public function set($route) {
 if ( is_array($route) ) {
 foreach ( $route as $regex => $control ) {
 $this->routes[$regex] = $control;
 }
 } else {
 $default_routes = $this->generate_default_routes($route);
 foreach ( $default_routes as $regex => $control ) {
 $this->routes[$regex] = $control;
 }
 }
 }
 /**
 * get routes
 */
 public function get_routes() {
 return $this->routes;
 }
 /**
 * Default routes
 */
 public function generate_default_routes($object) {
 ucfirst($object);
 return $routes = array(
 '~^\/'.$object.'s\/$~' => $object.'sController@list_all',
 '~^\/'.$object.'\/(\d+)\/$~' => $object.'sController@display',
 '~^\/admin\/'.$object.'s\/$~' => $object.'sController@list_all',
 '~^\/admin\/'.$object.'\/new\/$~' => $object.'sController@create',
 '~^\/admin\/'.$object.'\/(\d+)\/edit\/$~' => $object.'sController@edit',
 '~^\/admin\/'.$object.'\/(\d+)\/delete\/$~' => $object.'sController@delete',
 );
 }
 /**
 * set routes prefix
 */
 public function set_prefix($prefix) {
 foreach ( $prefix as $regex => $control ) {
 $this->prefix[$regex] = $control;
 }
 }
 /**
 * get requested url
 */
 public function set_url() {
 $url = isset($_GET['uri']) ? '/' . $_GET['uri'] . '/' : '';
 $this->url = urldecode(trim($url));
 }
 /**
 * get requested url
 */
 public function get_url() {
 return $this->url;
 }
 /**
 * Call the correct controller class and method
 */
 public function dispatch() {
 //find if the url match any specified route
 $args = $this->find_match($this->url, $this->routes);
 //set data
 $action = isset($args['action']) ? $args['action'] : '';
 $id = isset($args['id']) ? $args['id'] : '';
 $admin = isset($args['admin']) ? $args['admin'] : '';
 if ( !empty($action) ) {
 if ( preg_match('/@/', $action) ) {
 list($object, $method, $params) = $this->get_call_params($action, $id, $admin);
 call_user_func_array(array($object,$method), $params);
 } else {
 echo "invalid method supplied for the route: " . $this->url;
 }
 } else {
 echo "invalid route: " . $this->url;
 }
 }
 /**
 * find if the requested URL match any of the allowed route patterns
 */
 public function find_match($uri, $routes) {
 $args = array();
 foreach ( $routes as $regex => $controller) {
 if ( preg_match($regex, $uri) ) {
 $args['action'] = $controller;
 if ( preg_match('/([a-zA-Z]+)\/(\d+)/', $uri) ) {
 preg_match('/(\d+)/', $uri, $matches);
 $args['id'] = $matches[0];
 }
 if ( preg_match('~^\/admin/~', $uri) ) {
 preg_match('~^\/admin/~', $uri, $matches);
 $args['admin'] = $matches[0];
 }
 }
 }
 return $args;
 }
 /**
 * Prepare data for correct dispatching
 */
 public function get_call_params($action, $id, $admin) {
 //split action into controller and method
 $actions = explode('@', $action);
 list($controller, $method) = $actions;
 if ( !empty($admin) ) {
 $prefix = $this->prefix['admin'];
 } else {
 $prefix = $this->prefix['default'];
 }
 $controller = ucfirst($controller);
 //instantiate the controller object
 $class = 'Controller\\' . $controller;
 $object = new $class($action, $prefix);
 //set params array
 $params = array();
 $params[] = $id;
 return array($object, $method, $params);
 }
 }
}
?>

I use this routes.php file as routes configuration file, where I set the allowed paths objects for the paths patterns and the prefixes.

routes.php

<?php
/**
 * Allowed url pattern prefixes
 */
$router->set_prefix( array( 'default' => '' ) );
$router->set_prefix( array( 'admin' => 'admin' ) );
/**
 * Set up allowed URLs
 */
$router->set( array ( '/\//' => 'BaseController@index' ) );
$router->set( array ( '/login/' => 'Auth@login' ) );
$router->set( array ( '/logout/' => 'Auth@logout' ) );
$router->set( array ( '/admin/' => 'BaseController@admin_index' ) );
$router->set('page');
$router->set('user');
$router->set('cat');
$router->set('tag');
$router->set('media');
$router->set('option');
?>

• Arnold Daniels: Doing if ( !class_exists( 'Router' ) ) is bad for opcode caching. Instead use require_once to only load the php file that defines the class once.

Answer 1

Don't repeat yourself

 public function set($route) {
 if ( is_array($route) ) {
 foreach ( $route as $regex => $control ) {
 $this->routes[$regex] = $control;
 }
 } else {
 $default_routes = $this->generate_default_routes($route);
 foreach ( $default_routes as $regex => $control ) {
 $this->routes[$regex] = $control;
 }
 }
 }

can and should probably be written without duplicated logic :

 $routes = is_array($route) ? $route : $this->generate_default_routes($route);
 foreach ( $default_routes as $regex => $control ) {
 $this->routes[$regex] = $control;
 }

Similarly :

 if ( !empty($admin) ) {
 $prefix = $this->prefix['admin'];
 } else {
 $prefix = $this->prefix['default'];
 }

could become :

 $prefix = $this->prefix[empty($admin) : 'default' : 'admin'];

Style

You are a bit inconsistent in your vertical spacing. My personal point of view is that you don't need that many blank lines.