How does this control architecture script look? - php

Question

I am looking for feedback on my control architecture script (included below). Specifically, I am looking for feedback regarding the script's design, organization, commenting, and formatting. I enjoy php programming as a hobby, and am looking to learn where I can improve my code.
Thanks in advance!
class FrontController extends ActionController {
//Declaring variable(s)
private static $instance;
protected $controller;
//Class construct method
public function __construct() {}
//Starts new instance of this class with a singleton pattern
public static function getInstance() {
if(!self::$instance) {
self::$instance = new self();
}
return self::$instance;
}
public function dispatch($throwExceptions = false) {
/* Checks for the GET variables $module and $action, and, if present,
* strips them down with a regular expression function with a white
* list of allowed characters, removing anything that is not a letter,
* number, underscore or hyphen.
*/
$regex = '/[^-_A-z0-9]+/';
$module = isset($_GET['module']) ? preg_replace($regex, '', $_GET['module']) : 'home';
$action = isset($_GET['action']) ? preg_replace($regex, '', $_GET['action']) : 'frontpage';
/* Generates Actions class filename (example: HomeActions) and path to
* that class (example: home/HomeActions.php), checks if $file is a
* valid file, and then, if so, requires that file.
*/
$class = ucfirst($module) . 'Actions';
$file = $this->pageDir . '/' . $module . '/' . $class . '.php';
try {
//Checks for existance of file
if (!is_file($file)) {
throw new Exception('File not found!');
}
//Includes file
require_once $file;
/* Creates a new instance of the Actions class (example: $controller
* = new HomeActions();), and passes the registry variable to the
* ActionController class.
*/
$controller = new $class();
$controller->setRegistry($this->registry);
//Trys the setModule method in the ActionController class
$controller->setModule($module);
/* The ActionController dispatchAction method checks if the method
* exists, then runs the displayView function in the
* ActionController class.
*/
$controller->dispatchAction($action);
} catch(Exception $error) {
/* An exception has occurred, and will be displayed if
* $throwExceptions is set to true.
*/
if($throwExceptions) {
echo $error;
}
}
}
}
abstract class ActionController {
//Declaring variable(s)
protected $registry;
protected $module;
protected $registryItems = array();
//Class construct method
public function __construct(){}
public function setRegistry($registry) {
//Sets the registry object
$this->registry = $registry;
/* Once the registry is loaded, the controller root directory path is
* set from the registry. This path is needed for the controller
* classes to work properly.
*/
$this->setPageDir();
}
//Sets the controller root directory from the value stored in the registry
public function setPageDir() {
$this->pageDir = $this->registry->get('pageDir');
}
//Sets the module
public function setModule($module) {
$this->module = $module;
}
//Gets the module
public function getModule() {
return $this->module;
}
/* Checks for actionMethod in the Actions class (example: doFrontpage()
* within home/HomeActions.php) with the method_exists function and, if
* present, the actionMethod and displayView functions are executed.
*/
public function dispatchAction($action) {
$actionMethod = 'do' . ucfirst($action);
if (!method_exists($this, $actionMethod)) {
throw new Exception('Action not found!');
}
$this->$actionMethod();
$this->displayView($action);
}
public function displayView($action) {
if (!is_file($this->pageDir . '/' . $this->getModule() . '/' . $action . 'View.php')) {
throw new Exception('View not found!');
}
//Sets $this->actionView to the path of the action View file
$this->actionView = $this->pageDir . '/' . $this->getModule() . '/' . $action . 'View.php';
//Sets path of the action View file into the registry
$this->registry->set('actionView', $this->actionView);
//Includes template file within which the action View file is included
require_once $this->pageDir . '/default.tpl';
}
}
class Registry {
//Declaring variables
private $store;
//Class constructor
public function __construct() {}
//Sets registry variable
public function set($label, $object) {
$this->store[$label] = $object;
}
//Gets registry variable
public function get($label) {
if(isset($this->store[$label])) {
return $this->store[$label];
} else {
return false;
}
}
//Adds outside array of registry values to $this->store array
public function addRegistryArray($registryItems) {
foreach ($registryItems as $key => $value) {
$this->set($key, $value);
}
}
//Returns registry array
public function getRegistryArray() {
return $this->store;
}
}

Answer 1

Without having a detailed look on your code:
Try to write code that is self-explanatory by using meaningful function and variable names. Only use comments where the purpose or the functioning of your code is not clear. E.g.
//Declaring variable(s)
//Class construct method
//Checks for existance of file
//Includes file
are useless comments because the code itself is already clear enough.
A book worth reading: Clean Code

Answer 2

I am torn between closevoting as too localized and wanting to comment on the code. Also, it's too much code to wade through now, so I will comment only a few things:
1) Documentation style
Why not use an established documentation format, like PHPDoc?
2) Formatting
is consistent as far as I can see, but I suggest to use a coding convention that is in wide use, like that of PEAR or ZF (which is based on PEAR) instead of doing your own (yours is close to PEAR anyway, so you might as well adopt it completely).
3) Singleton pattern
In order for the Singleton to work it has to have a private __contruct and __clone method. But I suggest not to use it at all. Many people believe the Singleton is an AntiPattern. There are a number of questions on SO discussing the disadvantages of the Singleton pattern, so have a look around. If there should be only one instance, then simply dont instantiate a second one. If you need to access the FrontController in other classes, inject it.
4) Method length
I probably would try to shorten the dispatch method. Basically, if you describe what a method does and you have to use an and to do so, that part should go into it's own method. Try to make methods into small discrete units. That will make UnitTesting easier as well.
5) Separation of Concerns
I am not sure why the FrontController extends from ActionController. There is no other classes that extent it, butI suppose the classes the FrontController instantiates are subclasses of ActionController too. But the FrontController, while named a controller, does different things than the PageControllers, so I'd probably keep them separated.
On a sidenote, if you are interested in increasing the quality of your code, have a look at the slides and tools given at http://phpqatools.org/

Answer 3

Your code is very remeiscent of CakePhp. I'd recommend checking that out, it does all of this work with App::import() and a File class that wraps the filesystem. It's tested by a community on different versions and OSes, it will in fact save you time.