Before explaining a sample controller class, let's see the two classes which are needed for any controller. The classes are Application and Controller. Application is the class that executes important processes before the controller is created. In this case, it sets proper error reporting values, unregisters globals and escapes all input (GET, POST and COOKIE variables):

set_reporting();		$this->remove_magic_quotes();		$this->unregister_globals();	}		private function set_reporting() {		if (DEVELOPMENT_ENVIRONMENT == true) {	    error_reporting(E_ALL);	    ini_set('display_errors','On');		} else {		    error_reporting(E_ALL);		    ini_set('display_errors','Off');		    ini_set('log_errors', 'On');		    ini_set('error_log', ROOT.DS.'tmp'.DS.'logs'.DS.'error.log');		}	}		private function strip_slashes_deep($value) {    	$value = is_array($value) ? array_map(array($this,'strip_slashes_deep'), $value) : stripslashes($value);    	return $value;	}		private function remove_magic_quotes() {		if ( get_magic_quotes_gpc() ) {		    $_GET    = $this->strip_slashes_deep($_GET);		    $_POST   = $this->strip_slashes_deep($_POST);		    $_COOKIE = $this->strip_slashes_deep($_COOKIE);		}	}		private function unregister_globals() {	    if (ini_get('register_globals')) {	        $array = array('_SESSION', '_POST', '_GET', '_COOKIE', '_REQUEST', '_SERVER', '_ENV', '_FILES');	        foreach ($array as $value) {	            foreach ($GLOBALS[$value] as $key => $var) {	                if ($var === $GLOBALS[$key]) {	                    unset($GLOBALS[$key]);	                }	            }	        }	    }	}}

The Controller class is a generic controller class that inherits the Application class and contains important functions for communicating with models and views:

controller = $controller;       		 $this->action = $action;		$this->view = new View();	}		// Load model class	protected function load_model($model) {		if(class_exists($model)) {			$this->models[$model] = new $model();		}			}		// Get the instance of the loaded model class	protected function get_model($model) {		if(is_object($this->models[$model])) {			return $this->models[$model];		} else {			return false;		}	}		// Return view object	protected function get_view() {		return $this->view;	}}

There are also generic classes for models and views:

db = new MysqliDb(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);	}	}

Since models only communicate with the database, the role of this class is to load the database class and make it available inside all models. The database class file is named sql.php and the class itself can be downloaded from here.

View class contains functions required for using PHP variables inside views and for rendering HTML code:

variables[$name] = $value;    }         function render($view_name) {        extract($this->variables);				if( file_exists(ROOT . DS . 'application' . DS . 'views' . DS . $view_name . '.php') ) {			include (ROOT . DS . 'application' . DS . 'views' . DS . $view_name . '.php');		} else {			/* throw exception */								}    } }

Creating Your First Model, View and Controller

Let's create the first controller in this tutorial and call its class "Item." So, the filename will be item.php and it will be stored in application/controllers folder:

load_model('CategoryModel');		$this->load_model('ItemModel');	}		public function index() {		// Load search page		$this->search();	}		public function search()  {		// Call a model function		$items = $this->get_model('ItemModel')->getAll();						// Set view variables$this->get_view()->set('items', $items);// Render view		$this->get_view()->render('item/item_list_view');	}}

Each controller must inherit the core Controller class. The models are loaded for use inside a controller using the load_model function. Multiple models can be used in a controller.

The Index function is triggered when the following URL is requested: http://www.example.com/item/ (no 2nd parameter). In this case, we will just load the search function.

Models are created in application/models folder. The ItemModel class filename will be ItemModel.php:

db->get('item');	}	}

After creating a model and a controller, let's create a view named item_list_view.php:

render('common/meta'); 	$this->render('common/header');	?>
						id; ?>			name; ?>			
render('common/footer');?> 

Views are store inside application/views folder. Note that other views can be rendered inside the main view, which allows you to have partial views, such as header and footer.

Conclusion

We have just created a basic MVC framework. You can now see the theory from the first paragraph in practice ??controller does all the programming and calls the required models and views, models execute the database operations, and views only show HTML code (with the required PHP variables inserted).