Common Parent Classes to Extend in Magento 2

20th September 2017

Below shows a list of common parent classes to extend in Magento 2 when creating your own functionality that extends the Magento core application.

Blocks

If you need to add a frontend block class, the class should extend Magento\Framework\View\Element\Template.

<?php
namespace [Vendor]\[Module]\Block;

class YourBlock extends \Magento\Framework\View\Element\Template
{
}

Adminhtml blocks can extend from Magento\Backend\Block\Template, which in turn extend Magento\Framework\View\Element\Template.

<?php
namespace [Vendor]\[Module]\Block\Adminhtml;

class YourBlock extends \Magento\Backend\Block\Template
{
}

Controllers

To create a frontend controller class, ensure that you extend Magento\Framework\App\Action\Action.

<?php
namespace [Vendor]\[Module]\Controller\Index;

class Index extends \Magento\Framework\App\Action\Action
{
}

Adminhtml controllers extend from \Magento\Backend\App\Action, which include additional methods to check the user is authorised to view pages within the admin area.

<?php
namespace [Vendor]\[Module]\Controller\Adminhtml;

class YourController extends \Magento\Backend\App\Action
{
}

Helpers

Helpers can be created by extending the Magento\Framework\App\Helper\AbstractHelper class.

<?php
namespace [Vendor]\[Module]\Helper;

class YourHelper extends \Magento\Framework\App\Helper\AbstractHelper
{
}

Models

Models should extend from Magento\Framework\Model\AbstractModel.

<?php
namespace [Vendor]\[Module]\Model;

class YourModel extends \Magento\Framework\Model\AbstractModel
{
}

Resource Models

Similar to Magento 1, resource models and collections extend from different classes compared to a normal model.

Resource models should extend Magento\Framework\Model\ResourceModel\Db\AbstractDb.

<?php
namespace [Vendor]\[Module]\Model\ResourceModel;

class YourResourceModel extends \Magento\Framework\Model\ResourceModel\Db\AbstractDb
{
}

Collections

Collections should extend Magento\Framework\Model\ResourceModel\Db\Collection\AbstractCollection.

<?php
namespace [Vendor]\[Module]\Model\ResourceModel\[Entity];

class YourCollection extends \Magento\Framework\Model\ResourceModel\Db\Collection\AbstractCollection
{
}

Observers

Moving onto some implementation, observer class should implement the Magento\Framework\Event\ObserverInterface interface.

<?php
namespace [Vendor]\[Module]\Observer;

class YourObserver implements \Magento\Framework\Event\ObserverInterface
{
}

Sections

To add a custom section, which belongs in your module’s CustomerData directory, implement the Magento\Customer\CustomerData\SectionSourceInterface interface.

<?php
namespace [Vendor]\[Module]\CustomerData;

class YourSection implements \Magento\Customer\CustomerData\SectionSourceInterface
{
}

Setup classes

When adding new database tables using the InstallSchema, ensure that this class implements Magento\Framework\Setup\InstallSchemaInterface.

<?php
namespace [Vendor]\[Module]\Setup;

class InstallSchema implements \Magento\Framework\Setup\InstallSchemaInterface
{
}

Similar with UpgradeSchema classes, implement the Magento\Framework\Setup\UpgradeSchemaInterface interface.

<?php
namespace [Vendor]\[Module]\Setup;

class UpgradeSchema implements \Magento\Framework\Setup\UpgradeSchemaInterface
{
}

When installing data, using the InstallData class, ensure the class implements Magento\Framework\Setup\InstallDataInterface.

<?php
namespace [Vendor]\[Module]\Setup;

class InstallData implements \Magento\Framework\Setup\InstallDataInterface
{
}

UpgradeData classes should implement Magento\Framework\Setup\UpgradeDataInterface.

<?php
namespace [Vendor]\[Module]\Setup;

class UpgradeData implements \Magento\Framework\Setup\UpgradeDataInterface
{
}

And lastly, Uninstall classes should implement the Magento\Framework\Setup\UninstallInterface interface.

<?php
namespace [Vendor]\[Module]\Setup;

class Uninstall implements \Magento\Framework\Setup\UninstallInterface
{
}

Note: This article is based on Magento Open Source version 2.1.9.