Mangento INIT process

 

Magento INIT process bare Essen

Posted by Branko in magento | comments off

This
Article is meant to be a start up point for "newbies" getting ready
Digg seriously into the magetno. When I say newbie's, I meant no
Disrespect, I only ment new to magento. Because, you cannot be newbie
PHP developer and do something usefull with magento since it requires
Extensive knowledge of OOP and MVC.

Step 1: init/run the magento

File:
/Index. php

Code (from line 52 ):

Mage::run();

Eplanation:
MageIs the Class Name of/APP/MAGE. phpFile. MAGE class is of Type final, meaning you cannot extend it. In the code above, we are calling the static methodRun ()OnMageClass.

Step 2: Overview of static run () method

File:
/APP/MAGE. php

Code (from line 447 ):

public static function run($code = '', $type = 'store', $options=array()){    try {        Varien_Profiler::start('mage');         Varien_Profiler::start('mage::app');        self::app($code, $type, $options);        Varien_Profiler::stop('mage::app');         Varien_Profiler::start('mage::dispatch');        self::app()->getFrontController()->dispatch();        Varien_Profiler::stop('mage::dispatch');         Varien_Profiler::stop('mage');    }    ... /* exception handling code here, irrelevant for this example */}

Explanation:
InsideRun ()MethodMageClass two important things happen at the grand scale of things. Feel free to ignoreVarien_profiler: Start ()AndVarien_profiler: Stop ()
At this point since they are irrelevant for this base introductory.
Those two important things I mentioned are two method callinsied this
Run () method, and those are:

• SELF: APP ($ code, $ type, $ options);/* On Line 453 */
• SELF: APP ()-> getfrontcontroller ()-> dispatch ();/* On Line 457 */

Both of these method callpoint us to the same base method, so let's disect that in next step.

Step 3: overview of self: APP () method

File:
/APP/MAGE. php

Code (from line 416 ):

public static function app($code = '', $type = 'store', $options=array()){    if (null === self::$_app) {        Varien_Profiler::start('mage::app::construct');        self::$_app = new Mage_Core_Model_App();        Varien_Profiler::stop('mage::app::construct');         Mage::setRoot();        Mage::register('events', new Varien_Event_Collection());          Varien_Profiler::start('mage::app::register_config');        Mage::register('config', new Mage_Core_Model_Config());        Varien_Profiler::stop('mage::app::register_config');         Varien_Profiler::start('mage::app::init');        self::$_app->init($code, $type, $options);        Varien_Profiler::stop('mage::app::init');         self::$_app->loadAreaPart(Mage_Core_Model_App_Area::AREA_GLOBAL, Mage_Core_Model_App_Area::PART_EVENTS);    }    return self::$_app;}

Explanation:
InsideAPP ()Method We have several essenthings happening. Try to ignoreVarien_profiler: Start ()AndVarien_profiler: Stop ()Stuff. Now let's review the code. First we haveSELF: $ _ APP = new mage_core_model_app ()Called, saying store me and instaceMage_core_model_appInto my local (from the point of viewMageClass)$ _ AppVariable.

Note the definitionAPP ()Method, it'sAPP ($ code = ", $ type = 'store', $ Options = array ()).
It parameters es three main parameters (or none, in which case it uses
Defaults). Anyhow, this method call sets up entire object of TypeMage_core_model_appAnd stores it inMageClass local variable$ _ App.

Then we have three method CILS, one after other setting up pageMageClass Object:

• Mage: setroot ();
• Mage: Register ('events', new varien_event_collection ());
• Mage: Register ('config', new mage_core_model_config ());

After which we are pointed back to ourMage_core_model_appObject instance by following method cballs:

• SELF: $ _ app-> Init ($ code, $ type, $ options );
• SELF: $ _ app-> loadareapart (mage_core_model_app_area: area_global, mage_core_model_app_area: part_events );

Note thatSELF: $ _ appIs storing the instaceMage_core_model_appSo it's perfectly OK to call any public method thatMage_core_model_appClass has on this variable.

I will not go into the details of what both of those method CILS
Do, since this article wocould take hours and hours to be written in such
A way to cover all the inner workings details.

For now, let's just remember the return typeAPP ()Method call, returnSELF: $ _ app, It's the instanceMage_core_model_appClass. In short,APP ()Method sets up and returns entire app model.

Now, let's have a look back to step 2. There is one more method call left to be covered, we'll do that in Step 4

Step 4: Overview of self: APP ()-> getfrontcontroller ()-> dispatch ()

File:
/APP/code/CORE/MAGE/CORE/model/APP. php

Code (from line 857 ):

public function getFrontController(){    if (!$this->_frontController) {        $this->_initFrontController();    }     return $this->_frontController;}

Explanation:
Mage_core_model_appClass is all about setting currently running application instance options. method callGetfrontcontroller ()Returns the result of the privateMage_core_model_appMethod called_ Initfrontcontroller ().

While_ Initfrontcontroller ()CILS and sets$ This-> _ frontcontroller = new mage_core_controller_varien_front (), Where $ this variable is in contextMage_core_model_appClass, it returns$ This, Or in short, it returns current instaceMage_core_model_appClass.

SinceSELF: APP ()-> getfrontcontroller ()Method call returned us and object instance of TypeMage_core_model_appWe are allowed to chain a methodDispatch ()To it. Since this is the last method call insideRun ()Method ofMageClass file, this makes it a full circle.

Keep in mind that this is really, really, reallyMost basic intro
To magento's INIT process. There are a ton of stuff that happen
Each method call in this process and I only covered the most basic one.
For instance, when you calledSELF: APP ()You "triggered chained" cballs of your methods that might call other classes and Methods essential to build a instanceMage_core_model_app. Not to mention the inheritance and so on.

I find it a penpencil and a piece of paper to be a good tools
Tracking and "Drawing" yourself magento application inner workings.
Core things are really massive, a lot of file are involved into
Magento INIT process and lover core inner workings. It gets easy
Loose track of things jumping from one class to another.