The document explains Magento 2 plugins, which allow modification of class behavior without altering the original class using a design pattern called interception. Plugins can be implemented using before, after, or around listeners, each serving different purposes in method execution and value handling. It also details how to declare plugins in the module's di.xml file and outlines limitations such as issues with final methods and non-public methods.

1. Hello Everyone!

2. Magento2 Plugins
Rahul Mahto
Magento Developer

3. What is
Plugin?
➢Plugin is way to change
behaviour of a class without
changing the class.
➢Plugin allow us to change
behaviour of method of a
class.
➢Plugin is simply a design
pattern called interception.

4. Why Plugin?
➢It overcome the issues of
Rewriting System.
➢By plugin we can customize
same method in different
modules.

5. Request for object Class A Instance of Class A
Request for object Class A Instance of Class BClass B
Rewrited by
Normal Class flow. Requesting object for Class A and getting Instance of Class A.
Rewrited Class flow. Requesting object for Class A and getting Instance of Class B.

6. Request for object of Class A
Is class is
rewrited by
some Class
B?
Create instance of class B
Create instance of class A
No
Yes
Return created instance
END
START
Rewrited Class Flow

7. Types of
Plugin?
In Magento2 we can use plugin in 3
ways.
➢Using before listener
➢Using after listener
➢Using around listener

8. Declare a
Plugin
Plugin is called by adding prefix
‘before’, ‘after’ or ‘around’ to the
method name and setting first letter
of original method to capital.
Original method Name - getName()
Plugin Method Name -
beforeGetName(), afterGetName()
or aroundGetName()

9. Define plugin in module’s di.xml file
<config>
<type name="{ObservedType}">
<plugin name="{pluginName}" type="{PluginClassName}" sortOrder="1"
disabled="true"/>
</type>
</config>

10. type name - A class which the plugin observes.
plugin name - Name that identifies a plugin.
type - The name of a plugin’s class.
Optional Elements:
sortOrder - The order in which plugins that call the same method are run.
disabled - To disable a plugin

11. Before
Listener
➢Used to change arguments of
method.
➢Used to add some behavior
before an original method is
called.
➢Do not need to have a return
value.

14. **Logos and Trademarks are owned by
their respective owners

15. After
Listener
➢Used to change values returned
by an original method.
➢Used to add some behavior
after an original method is
called.
➢Do not need to have a return
value.

18. **Logos and Trademarks are owned by
their respective owners

19. **Logos and Trademarks are owned by
their respective owners

20. Around
Listener
➢Used to change both the
arguments and the returned
values of an original method.
➢Used to add some behavior
before and after an original
method is called.
➢Must have a return value.

22. Behind the
Scene
➢Interceptor class is generated
➢Extended by original class
➢It contains all public method
➢It checks for plugin in methods
➢Process all plugins
➢Return result

23. Request for object of Class A
Does class
contain
Plugin?
Generate Interceptor Class for A.
Return Instance of Class A
No
Yes
Return Instance of Interceptor
Class
END
START
Plugin System Flow

24. Request a Method
Does this
method
contain
Plugin?
Process Plugins
Return Result
No
Yes
Return Result
END
START
Plugin System Flow

26. Method in Original Class of Product Model in Magento2

27. Method in Interceptor Class of Product Model in Magento2

29. Limitations
➢Objects instantiated before
MagentoFrameworkIntercept
ion
➢Final methods and Final
classes
➢Non-public methods
➢__construct
➢Virtual types

30. Thank You!