Writing a Php5 MVC Framework like Code Igniter Part1: Controller,view,registry,loader

Some times we want a  flexible and basic framework for our small pretty applications. In this tutorial (in section part 1) we will start a  base framework  using MVC structure , we will create a Controller , View (template system) and  some base structures like  Registry - Loader. i call it Obullo framework. 

Below the picture show directory structure of Obullo framewok.

obullo framework directory structure

/**
 * Obullo Framework (c) 2009.
 *
 * PHP5 MVC Framework software for PHP 5.2.4 or newer
 *
 * @package        obullo
 * @filename        system/libraries/Registry.php
 * @author          obullo.com
 * @copyright      Ersin Güvenç (c) 2009.
 * @since            Version 1.0
 * @filesource
 * @license
 */

abstract class Obullo_Registry
{
    abstract protected function get($key);
    //get stored object.
    abstract protected function set($key,$val);
    //set (store) object.
} 

Class Object_Registry extends Obullo_Registry {

    /**
    * Registry array of objects
    * @access private
    */
    private static $objects = array();

    /**
    * The instance of the registry
    * @access private
    */
    private static $instance;

    //prevent directly access.
    private function __construct(){}
    //prevent clone.
    public function __clone(){}

    /**
    * singleton method used to access the object
    * @access public
    */
    public static function singleton()
    {
        if(!isset(self::$instance))
        {
        self::$instance = new self();
        //echo "new instance";
        } else {
        //echo "old instance";
        }
        return self::$instance;
    }

    protected function get($key)
    {
        if(isset($this->objects[$key]))
        {
            return $this->objects[$key];
        }
        return NULL;
    }

    protected function set($key,$val)
    {
        $this->objects[$key] = $val;
    }

    //static get request handle
    static function getObject($key)
    {

        return self::singleton()->get($key);
    }

    //store object
    static function storeObject($key, $instance)
    {

        return self::singleton()->set($key,$instance);
    }

} //end of the class.

/**
* Registry Controller Function
* @param - 1  string   name of the class its not instance.
* @param - 2  array    __construct params of instance.
* @access public
*/

function Register($class)
{
    $Obj = Object_Registry::singleton();

    $Class = strtolower($class); //lowercase classname.

    //if class already stored we are done.

    if ($Obj->getObject($Class) !== NULL)
    {
        //echo "ok";
        return $Obj->getObject($Class);

    }                           

    if(file_exists(SYS.'libraries'.DIRECTORY_SEPARATOR.ucfirst($Class).EXT))
    {
        require(SYS.'libraries'.DIRECTORY_SEPARATOR.ucfirst($Class).EXT);

    } elseif(file_exists(APP.'libraries'.DIRECTORY_SEPARATOR.$Class.EXT)) 

    {
        require(APP.'libraries'.DIRECTORY_SEPARATOR.$Class.EXT);
    }

    //declare class instance.
    //store object.
    $classname = ucfirst($class);
    $Obj->storeObject($Class, new $classname()); 

    //return singleton object.
    $Object = $Obj->getObject($Class);

    if(is_object($Object))
    return $Object;

} //end function.

We talk about PHP5 registry before at here: php5-object-registry-implementation-a-registry-design-pattern
We have a registry function now we can create main Controller file.

/**
 * Obullo Framework (c) 2009.
 *
 * PHP5 MVC Framework software for PHP 5.2.4 or newer
 *
 * @package         obullo
 * @filename        system/libraries/Controller.php
 * @author          obullo.com
 * @copyright       Ersin Güvenç (c) 2009.
 * @since           Version 1.0
 * @filesource
 * @license
 */                       

class OB_root extends Loader
{

public $load;
    //or storeObject(key,$this) getObject
    private static $instance;

    public function __construct()
    {
        parent::__construct();
        $this->load = $this;
        //self::$instance = $this;
        self::$instance = $this->load;

    }

    public static function getInstance()
    {
        return self::$instance;
    }

}

Class Controller extends OB_root
{

    function __construct()
    {

        $this->ob_init();
        parent::__construct();
        //$this->db   = Register('Db');
    }

    function ob_init()
    {
      /*
      *  we assing to load variable main loader class.
      *  we will use loader like this
      *  $this->load->library('file') //load class from library dir.
      *  $this->load->helper('file')  //load helper file from helper dir.
      */
      //$this->load =& Register('Loader');

      //load internal system classes...
      //WE CAN USE THIS CLASSES in controller like  $this->cookie->item
      //without use load word.

      $Classes = array(
                        'session'    => 'Session',
                        'cookie'     => 'Cookie'
                        );

        foreach ($Classes as $public_var => $Class)
        {
            $this->$public_var = Register($Class);
        }

        //from now on we can use session class
        //like this $this->session->set(); 

    } //end function.

} //end of the class.

//Get Super Object's Instance.
function OB_instance()
{
    return OB_root::getInstance();
}  

User Controller file (Controller/test.php) extends to Main Controller file and Main Controller initialize Obullo system classes.Now we need to a loader file for $this->load->view, $this->load->library operations.

/**
 * Obullo Framework (c) 2009.
 *
 * PHP5 MVC Framework software for PHP 5.2.4 or newer
 *
 * @package         obullo
 * @filename        system/libraries/Loader.php
 * @author          obullo.com
 * @copyright       Ersin Güvenç (c) 2009.
 * @since           Version 1.0
 * @filesource
 * @license
 */ 

Class Loader
{

    function __construct(){}

    /*
    *  Load classes from application/libraries directory.
    */
    public function library($class='')
    {
        if ($class == '') return false;

        $Clasname   = ucfirst(strtolower($class));
        $PublicVar  = strtolower($class);

        // Instantiate the Super Object.
        $OB =& OB_instance();
        $OB->$PublicVar = Register($class);

        //from now on we can use own library
        //like $this->Myclass->myMethod
    }

    /*
    *  main view function.
    */
    public function view($view, $data=array(), $string=false)
    {
        $file = VIEW . DIRECTORY_SEPARATOR . $view . EXT;
        if(sizeof($data) > 0)
        extract($data, EXTR_SKIP);
        //foreach($data as $key=>$value) $$key = $value;

        if (file_exists($file)) {

                if($string) {

                //get file as a srtring.
                ob_start();

                //look at code igniter similarity ->> system/libraries/loader.php line 671.
                //echo eval(file_get_contents($file));
                include($file);

                $content = ob_get_contents();
                ob_end_clean();

                return $content;

                } else {

                //just include file.
                include($file);
                }

        } else {
            die("Can't load template file: " . $file);
            //throw new Exception..
            return false;
        }

        return true;
    }

    public function model()
    {
       //we will write it later..
    }

} //end of the class.

We extends from Controller file to Loader and we can use call classes as $this->load->library(class).Loader file contains view and model structures..
Now we create our first Controller/test.php file.

/*
*  Our first controller controllers/test.php
*
*/

Class Test extends Controller
{

public $sample_var = "you can use variable from view";    

    function __construct()
    {
        parent::__construct();

        //load your class.
        $this->load->library('myclass');

    }                               

    function run()
    {
        echo "Run function succesfully works.<br /><br />";

        $data['sample_array'] = array('1','2','3','4','5');
        $data['example_var'] = "Hello World!";

        //example library class.
        $this->myclass->testMe(1,2); 

        echo "<br />";

        //example a system/library class: session.
        $this->session->set("test","Session variable succesfully works!");
        echo $this->session->get("test");

        //example view.
        $this->load->view("view_test_run",$data);
        //fetch as string  $this->view("run",$data,true);
    }

} //end of the class.

and we can run index.php file

$OB = new $Class();
//You can also set a var from outside of the class like this.
//$OB->name = "My Name";

$arg_array = array(); //write your arguments here...
call_user_func_array(array($OB, $Method), $arg_array);

and result..

Result

Download .Zip File: Obullo Framework 1.0