The Magento folder structure

The Magento folder structure is slightly different from other MVC applications. Let's take a look at the directory tree, and each directory and its functions:

• app: This folder is the core of Magento and is subpided into three important directories:
  • code: This contains all our application code pided into three code pools, namely core, community, and local
  • design: This contains all the templates and layouts for our application
  • locale: This contains all the translation and e-mail template files used for the store
• js: This contains all the JavaScript libraries that are used in Magento
• media: This contains all the images and media files for our products and CMS pages, as well the product image cache
• lib: This contains all the third-party libraries used in Magento (such as Zend and PEAR) as well as the custom libraries developed by Magento, which reside under the Varien and Mage directories
• skin: This contains all CSS, images and JavaScript used by the corresponding theme
• var: This contains our temporary data, such as the cache file, index lock files, sessions, import/export files, and in the case of the Enterprise edition, the full page cache folders

Magento is a modular system. This means the application, including the core, is pided into smaller modules. For this reason, the folder structure plays a key role in the organization of each module. A typical Magento module folder structure would look something like this:

Let's review each folder further:

• Block: In Magento, blocks form an additional layer of logic between the controllers and views
• controllers: These are formed by actions that process webserver requests
• Controller: Classes in this folder can be abstract classes and they can be extended by the controller class under the controllers folder
• etc: In this we can find the module-specific configuration in the form of XML files such as config.xml and system.xml
• Helper: This contains auxiliary classes that encapsulate a common module functionality and make them available to a class of the same module and to other modules classes as well
• Model: This contains models that support the controllers in the module to interact with data
• sql: These contain the installation and upgrade files for each specific module
• data: This folder was introduced in Magento 1.6 CE and it is used in a manner similar to SQL scripts, but data scripts are only concerned about inserting data

As we will see later in this chapter, Magento makes heavy use of factory names and factory methods. This is why the folder structure is so important.