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How to Use Events and Observers in Magento 2

In the world of ecommerce, there are many ecommerce platforms, with Magento 2 being on top of the list.  It is a great option for users who are looking for a secure and customizable ecommerce platform with loads of awesome features.

There are different ways of extending the core functionality of a Magento 2 powered ecommerce store, and working with Magento 2 events and observers is one of the main ways among them. With the help of them, you can run your custom codes in response to a specific Magento event or even with a custom event.

So, today in this guide I am going to teach you, how to use events and observers in Magento 2. But before going towards the implementation, let’s first understand about Magento 2 events and observers:

Magento 2 Events

Events are dispatched by Magento modules on the trigger of a specific action. Not only that, Magento also allows you to also create your own custom event that can be dispatched in your code. When the action is triggered, it will pass data to the relevant observer configured for the dispatched event.

Magento 2 events can be dispatched using Magento\Framework\Event\Manager class and it can be obtained through the dependency injection by defining the dependency in your constructor.

Magento 2 Observers

Observers are used to catch the action which was triggered from events. In observers, you can set the required functionality or logic that is to be executed in response.

Magento 2 observers can be created by lacing your class file under the Module-Root/Observer directory. Your observer class should implement the following;

Magento\Framework\Event\ObserverInterface and define its execution function.

Now let’s start with the execution!

Let’s assume that you want to change the background color of your store if the customer is not logged in.

Use Magento 2 Event and Observer

I will start by creating a custom Magento 2 module:

Configuration of Module

For configuration of a custom module, create a module.xml file in app/code/Magenticians/Mymodule/etc and add this code in it:

Registration of Module

For registration of module, create a registration.php file in app/code/Magenticians/Mymodule and add this code in it:

Create a Magento 2 Event

To create a Magento 2 event, add a new file events.xml in app/code/Magenticians/Mymodule/etc/frontend and add this code to it:

In the above code, I have used  layout_load_before  in the name attribute of the event element. Then in the observer elements, add_layout_handles  in the name attribute and Magenticians\Mymodule\Observer\AddHandles in the instance attribute. The observer name must be unique for each event.

Create a Magento 2 Observer

Now to create Magento 2 observer, add a new file AddHandles.php in app/code/Magenticians/Mymodule/Observer and add this code to it:

In the above code, you can see the constructor for customer session. And you can also see the execute function that I added the handle customer_logged_out to the layout.

Create a Layout File

As I mentioned in the previous step about the handle customer_logged_out. For that, create a file customer_logged_out.xml in app/code/Magenticians/Mymodule/view/frontend/layout and add this code to it:

In the above code, I set the path of CSS file under <head>  which will execute for guest users.

Create a CSS File

Now create the CSS file which is mentioned in customer_logged_out.xml file.  To do that, add customcolor.css file in app/code/Magenticians/Mymodule/view/frontend/web/css and add this code to it:

In the above code, I have set backgorud color which will apply only on guest users.

Run CLI Commands

Launch SSH terminal and connect your Magento 2 store. Then go to its root directory to run the following commands:

First, run this command:

rm -rf var/di/* var/generation/* var/cache/* var/log/* var/page_cache/* var/session/* var/view_preprocessed/* pub/static/*

To upgrade the setup:

php bin/magento setup:upgrade

To compile the setup:

php bin/magento setup:di:compile

To deploy static content:

php bin/magento setup:static-content:deploy -f

To re-index:

php bin/magento indexer:reindex

To clean and flush the cache:

php bin/magento cache:clean

php bin/magento cache:flush

All done, it’s time to check the output. Go to your store’s front page as a guest user and you will see the background color of your store is changed:

events observers magento 2 result

This means you have successfully implemented events and observer in Magento 2.

Wrapping Up

Events and observers should help you in adding more functionality to your Magento 2 powered store. I have just shown you an example of using Magento 2 events and observers, you can extend it according to your needs and requirements. After following this guide, I hope you’ve learned how to use Magento 2 events and observers. If you still have any confusions or want to discuss anything related to this tutorial, drop your comment below and I will get back to you!


About Author

Syed Muneeb Ul Hasan is an expert in PHP and Magento, he prefers to educate users in implementing and learning Magento. When not working, he loves to watch cricket.