Magento 2.x Events and Observers

Magento 2 events are used to run custom code in response to any particular Magento 2 event or custom event. Events are dispatched by modules when certain actions are triggered. When an event is dispatched, it can pass data to any observers configured to watch that event.

Events are dispatched by Magento 2 modules whenever specific actions are triggered. When an event dispatches, it passes data to the observer that is configured to watch (or monitor) that event. You can dispatch Magento 2 Events using the Magento\Framework\Event\Manager class

List of All Events Magento 2 Events-Attachment-PDF-Format

Observers are the particular classes that control the general behavior, performance, or change in the business logic

Which class file is used to create Observers

To create an observer in Magento 2, you must place your class file under the ModuleRoot/Observer directory. The observer class file should use

Magento\Framework\Event\Observer

&

Magento\Framework\Event\ObserverInterface

class and define the executive function.

Declaration Observer

There are following below method to declare observer

“Observer will be executed in all areas: adminhtml, crontab, frontend, graphql, webapi_rest, webapi_soap”

[1]- Observer Global Declaration :

magento2rootdirectory/app/code/vendorname_modulename/etc/events.xml

[2] Observer Frontend Declaration :

magento2rootdirectory/app/code/vendorname_modulename/etc/frontend/events.xml

[3] Observer Adminhtml Declaration :

magento2rootdirectory/app/code/vendorname_modulename/etc/adminhtml/events.xml

[4] Observer Graphql Declaration :

magento2rootdirectory/app/code/vendorname_modulename/etc/graphql /events.xml

[5] Observer Crontab Declaration :

magento2rootdirectory/app/code/vendorname_modulename/etc/crontab/events.xml

[6] Observer RestAPI Declaration :

magento2rootdirectory/app/code/vendorname_modulename/etc/webapi_rest /events.xml

[7] Observer SAOPAPI Declaration :

magento2rootdirectory/app/code/vendorname_modulename/etc/webapi_soap/events.xml