A talk I gave at Mage Titans Italy 2018: http://www.magetitans.it/speakers/joke-puts/ How can you make Magento do what you want? In Magento 2 there are a lot of ways to add customizations. What are your options? Can you do a rewrite like in Magento 1? Should you use an event to add that business-critical logic when your invoice reaches state paid? Or is a plugin a better option? Maybe it’s the only option. What’s the deal with dependency injection and why do I need interfaces? In this talk we’re going to explore all the possibilities.

1. MANIPULATING MAGENTO
Make it do what you want
PHP developer at
Joke Puts - @jokeputs

2. Goal
Bug free and future proof
customizations

3. How
Keep the interactions with
the core to a minimum

4. Topics
• Preferences
• Plugins
• Observers
• Cases

5. PREFERENCE
Replacing behavior through dependency injection

6. Dependency injection
“Dependency injection is the concept
of the external environment injecting
dependencies for an object instead
of that object manually creating them
internally.”

7. Dependency injection
• Constructor injection
• Object manager

8. MagentoQuoteModelQuoteAddressValidator
public function __construct(
AddressRepositoryInterface $addressRepository,
CustomerRepositoryInterface $customerRepository,
Session $customerSession
) {
$this->addressRepository = $addressRepository;
$this->customerRepository = $customerRepository;
$this->customerSession = $customerSession;
}

9. Interfaces
• API directory
• Service contract
• (Relatively) stable across upgrades

10. MagentoFrameworkObjectManagerObjectManager
public function create(
$type, array
$arguments = []
) {
$type = ltrim($type, '');
return $this->_factory->create(
$this->_config->getPreference($type),
$arguments
);
}

11. di.xml
<preference
for="MagentoCustomerApiDataCustomerInterface"
type="MagentoCustomerModelDataCustomer" />

12. module.xml
<module name="Namespace_Module"
setup_version="1.0.0">
<sequence>
<module
name="Magento_Customer"/>
</sequence>
</module>

13. <module name="PHPro_AModule"
setup_version="1.0.0">
<sequence>
<module name="Magento_Customer"/>
</sequence>
</module>
<module name="PHPro_ZModule"
setup_version="1.0.0">
<sequence>
<module name="Magento_Customer"/>
</sequence>
</module>

14. PLUGINS
Adding and modifying behavior before, after and
around

15. Plugin
“A plugin is a class that modifies the
behavior of public class functions by
running code before, after or around
that function call.”

16. di.xml
<type
name="MagentoCatalogModelResourceModelCate
gory">
<plugin name="category_delete_plugin"
type="MagentoCatalogUrlRewriteModelCat
egoryPluginCategoryRemove"/>
</type>

17. Before
• Runs before the method
• Modifies the arguments of the
method
• Returns null to indicate that the
arguments haven’t changed

18. Before
public function beforeSetName(
Product $subject,
$name
) {
// Do something
}

19. After
• Runs after the method
• Modifies the output of the method
• Should have a return value

20. After
public function afterGetName(
Product $subject,
$result
) {
// Do something
return $result;
}

21. Around
• Runs both before and after the
method
• Modifies the entire method
• Access to arguments and output
• Receives a callable

22. Around
public function aroundUpdateData(
Address $subject,
callable $proceed,
AddressInterface $address
) {
// Do something
$result = $proceed($address);
// Do something
return $result;
}

23. Not calling the callable
✖Other around plugins (sort order)
✖Other after plugins (sort order)
✖Original method

24. Call order prior original
1. Sort order from low to high
2. Order of the uasort() array
3. Before plugins
4. Around plugins (before calling the
callable)

25. Call order post original
1. Sort order from high to low*
2. Reversed order of the uasort()
array
3. Around plugins (after calling the
callable)
4. After plugins
* Only if an around plugin exists

26. PHPro/AModule/etc/di.xml à after plugin
<type
name="MagentoStoreModelAddressRenderer">
<plugin name="renderer_a"
type="PHProAModulePluginRenderer"
sortOrder="10"/>
</type>
PHPro/ZModule/etc/di.xml à after plugin
<type
name="MagentoStoreModelAddressRenderer">
<plugin name="renderer_z"
type="PHProZModulePluginRenderer"
sortOrder="20"/>
</type>

27. OBSERVERS
Modifying data and running new behavior

28. Observers
“Observers are executed whenever
the event they are configured to
watch is dispatched by the event
manager.”

29. MagentoCustomerModelSession
public function
setCustomerAsLoggedIn($customer)
{
$this->setCustomer($customer);
$this->_eventManager->dispatch(
'customer_login',
['customer' => $customer]
);

30. events.xml
<event name="customer_login">
<observer name="wishlist"
instance="MagentoWishlistObserver
CustomerLogin" />
</event>

31. MagentoWishlistObserverCustomerLogin
class CustomerLogin implements
ObserverInterface
{
public function execute(
Observer $observer
) {
$this->wishlistData->calculate();
}
}

32. Events
• Find events in the core
• Look at the passed data
• $observer->getEvent()
->get{key}()

33. Model events
• {event_prefix}_load_before
• {event_prefix}_load_after
• {event_prefix}_save_before
• {event_prefix}_save_after
• {event_prefix}_delete_before
• {event_prefix}_delete_after
• {event_prefix}_save_commit_after
• {event_prefix}_delete_commit_after
• {event_prefix}_clear

34. Model events
• Extend MagentoFrameworkModel
AbstractModel
• Set $_eventPrefix
• Set $_eventObject

35. Collection events
• {event_prefix}_load_before
• {event_prefix}_load_after

36. Collection events
• Extend MagentoFrameworkModel
ResourceModelDbCollection
AbstractCollection
• Set $_eventPrefix
• Set $_eventObject

37. Controller events
• controller_action_predispatch_{route_name}
• controller_action_predispatch_{full_action_name}
• controller_action_postdispatch_{full_action_name}
• controller_action_postdispatch_{route_name}

38. Controller events
• Extend
MagentoFrameworkAppAction
Action

39. Dispatch order
1. Observers in the global area
a. Module sequence order
b. Order in events.xml
2. Observers in adminhtml or frontend area
a. Module sequence order
b. Order in events.xml

40. PHPro/AModule/etc/adminhtml/events.xml
<event name="sales_order_save_after">
<observer name="phpro_a_order_save"
instance="PHProAModuleObserverAfterOrderSa
ve" />
</event>
PHPro/ZModule/etc/events.xml
<event name="sales_order_save_after">
<observer name="phpro_z_order_save"
instance="PHProZModuleObserverAfterOrderSa
ve" />
</event>

41. RECAP
What should I use?

42. Preferences
Replace behavior

43. Preferences
• (+) Replace entire class or interface
implementation
• (-) Only one preference can be active
• (-) Replace entire class to replace one
line of code

44. Plugins
Add and modify behavior

45. Plugins
• (+) Manipulate behavior before, after
and around one method
• (+) Access to arguments and output
• (+) Multiple plugins for one method
• (-) Only public methods

46. Observers
Modify passed data and start new behavior

47. Observers
• (+) Multiple observers for one event can
be active
• (-) Event has to exist
• (-) Only access to the passed data

48. CASES
Enough with the theory…

49. Case #1
Modify the JSON response from
an external module

50. Case #2
Call an external service
when an order reaches
the state “complete”

51. Case #3
Redirect to a store view based
on the customer’s location
(full page cache)

52. Case #4
Customers are not stored in Magento
and should be accessed using an
external service

53. Case #5
Change the store address
template in an e-mail template

55. Questions?
https://joind.in/talk/0bb46