This document discusses code generation in Magento 2. It generates code for dependency injection such as factories and proxies. It also generates code for interceptors to implement plugins. Code is generated for the service layer including repositories, persistors, search results, and extension attributes. Loggers are also generated to log method calls. Code generation allows writing code at a higher level of abstraction and avoids boilerplate code.

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@SergiiShymko
Senior Software Engineer
Magento, an eBay Inc. company
Code Generation
in Magento 2

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Introduction to Code Generation
• Automatic programming – generation of computer program
• Source code generation
– Generation based on template
• Allows to write code at higher abstraction level
• Enables aspect-oriented programming (AOP)
• Enables generic programming – parameterization over types
• Avoids writing boilerplate code

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Code Generation in Magento 1.x

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Code Generation in Magento 2

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Code Generation in Magento 2
• Code is generated:
– On the fly (development)
• Autoload non-existing class that follows naming pattern
– Beforehand (production)
• Run CLI tools
php dev/tools/Magento/Tools/Di/compiler.php
• Location of generated code:
var/generation/

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Factories
• Factory creates objects
• Single method – create()
• Used for non-injectables, i.e. entities
• Isolation from Object Manager
• Type safety
• IDE auto-completion
• Class name pattern:
NamespaceClassFactory

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Factory Usage
namespace MagentoCatalogModelProduct;
class Copier
{
public function __construct(
MagentoCatalogModelProductFactory $productFactory
) {
$this->productFactory = $productFactory;
}
public function copy(MagentoCatalogModelProduct $product) {
$duplicate = $this->productFactory->create();
// ...
}
}
app/code/Magento/Catalog/Model/Product/Copier.php

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Generated Factory (Simplified)
namespace MagentoCatalogModel;
class ProductFactory
{
public function __construct(
MagentoFrameworkObjectManagerInterface $objectManager
) {
$this->objectManager = $objectManager;
}
public function create(array $data = array()) {
return $this->objectManager->create(
'MagentoCatalogModelProduct',
$data
);
}
}
var/generation/Magento/Catalog/Model/ProductFactory.php

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Proxies
• Implementation of GoF pattern
• Follows interface of subject
• Delays creation of subject
– Delays creation of dependencies
• Forwards calls to subject
• Used for optional dependencies of DI
• Class name pattern:
NamespaceClassProxy

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Proxy Usage in DI Config
<config>
<type name="MagentoCatalogModelResourceProductCollection">
<arguments>
<argument name="customerSession" xsi:type="object">
MagentoCustomerModelSessionProxy
</argument>
</arguments>
</type>
</config>
app/code/Magento/Catalog/etc/di.xml

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Generated Proxy (Simplified)
namespace MagentoCustomerModelSession;
class Proxy extends MagentoCustomerModelSession
{
protected function getSubject() {
if (!$this->subject) {
$this->subject = $this->objectManager->get(
'MagentoCustomerModelSession'
);
}
return $this->subject;
}
public function getCustomerId() {
return $this->getSubject()->getCustomerId();
}
// ...
}
var/generation/Magento/Customer/Model/Session/Proxy.php

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Interception
• Primary customization approach
• AOP-like mechanism
• Used for plugins
• Attach behavior to public methods
– Before
– After
– Around
• Plugins declared in DI config

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Plugin Implementation
namespace MagentoStoreAppActionPlugin;
class StoreCheck
{
public function aroundDispatch(
MagentoFrameworkAppActionAction $subject,
Closure $proceed,
MagentoFrameworkAppRequestInterface $request
) {
if (!$this->storeManager->getStore()->getIsActive()) {
throw new MagentoFrameworkAppInitException(
'Current store is not active.'
);
}
return $proceed($request);
}
}
app/code/Magento/Store/App/Action/Plugin/StoreCheck.php

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Plugin Declaration in DI Config
<config>
<type name="MagentoFrameworkAppActionAction">
<plugin name="storeCheck"
type="MagentoStoreAppActionPluginStoreCheck"
sortOrder="10"/>
</type>
</config>
app/code/Magento/Store/etc/di.xml

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Generated Interceptor (Simplified)
namespace MagentoFrameworkAppActionAction;
class Interceptor extends MagentoFrameworkAppActionAction
{
public function dispatch(
MagentoFrameworkAppRequestInterface $request
) {
$pluginInfo = $this->pluginList->getNext(
'MagentoFrameworkAppActionAction', 'dispatch'
);
if (!$pluginInfo) {
return parent::dispatch($request);
} else {
return $this->___callPlugins(
'dispatch', func_get_args(), $pluginInfo
);
}
}
}
var/generation/Magento/Framework/App/Action/Action/Interceptor.php

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Code Generation for Service Layer
• Service layer – ultimate public API
• Services implement stateless operations
• Generated code:
– Repository*
– Persistor*
– Search Results
– Extension Attributes
* – may be removed in future releases

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Generated Repository (Simplified)
namespace MagentoSalesApiDataOrder;
class Repository implements MagentoSalesApiOrderRepositoryInterface
{
public function __construct(
MagentoSalesApiDataOrderInterfacePersistor $orderPersistor,
MagentoSalesApiDataOrderSearchResultInterfaceFactory $searchResultFactory
) {
$this->orderPersistor = $orderPersistor;
$this->searchResultFactory = $searchResultFactory;
}
public function get($id);
public function create(MagentoSalesApiDataOrderInterface $entity);
public function getList(MagentoFrameworkApiSearchCriteria $criteria);
public function remove(MagentoSalesApiDataOrderInterface $entity);
public function flush();
}
var/generation/Magento/Sales/Api/Data/Order/Repository.php

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Extension Attributes
• Extension to data interfaces from 3rd party modules
• Attributes declared in configuration
• Attribute getters/setters generated
• Type-safe attribute access
• IDE auto-completion
• Class name pattern:
NamespaceClassExtensionInterface
NamespaceClassExtension

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Declaration of Extension Attributes
<config>
<custom_attributes for="MagentoCatalogApiDataProductInterface">
<attribute code="price_type" type="integer" />
</custom_attributes>
</config>
app/code/Magento/Bundle/etc/data_object.xml

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Entity with Extension Attributes
namespace MagentoCatalogApiData;
interface ProductInterface
extends MagentoFrameworkApiCustomAttributesDataInterface
{
/**
* @return MagentoCatalogApiDataProductExtensionInterface|null
*/
public function getExtensionAttributes();
public function setExtensionAttributes(
MagentoCatalogApiDataProductExtensionInterface $attributes
);
// ...
}
app/code/Magento/Catalog/Api/Data/ProductInterface.php

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Generated Interface of Extension Attributes
namespace MagentoCatalogApiData;
interface ProductExtensionInterface
extends MagentoFrameworkApiExtensionAttributesInterface
{
/**
* @return integer
*/
public function getPriceType();
/**
* @param integer $priceType
* @return $this
*/
public function setPriceType($priceType);
// ...
}
var/generation/Magento/Catalog/Api/Data/ProductExtensionInterface.php

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Generated Implementation of Extension Attributes
namespace MagentoCatalogApiData;
class ProductExtension
extends MagentoFrameworkApiAbstractSimpleObject
implements MagentoCatalogApiDataProductExtensionInterface
{
/**
* @return integer
*/
public function getPriceType() {
return $this->_get('price_type');
}
/**
* @param integer $priceType
* @return $this
*/
public function setPriceType($priceType) {
return $this->setData('price_type', $priceType);
}
// ...
}
var/generation/Magento/Catalog/Api/Data/ProductExtension.php

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Loggers
• Implementation of GoF pattern Decorator
• Activated with the profiler
– Object Manager wraps instances with loggers
• Tracks method call stack
• Forwards calls to original methods
• Class name pattern:
NamespaceClassLogger

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Summary of Code Generation
• DI
– Factory
– Proxy
• Interception
• Service Layer
– Repository
– Persistor
– Search Results
– Extension Attributes
• Logger

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Thank You!
Q & A
@SergiiShymko
sshymko@ebay.com
sergey@shymko.net