{"id":3478,"date":"2024-08-29T10:38:59","date_gmt":"2024-08-29T10:38:59","guid":{"rendered":"https:\/\/www.rcvtechnologies.com\/blog\/?p=3478"},"modified":"2024-11-13T12:36:16","modified_gmt":"2024-11-13T12:36:16","slug":"opencart-event","status":"publish","type":"post","link":"https:\/\/www.rcvtechnologies.com\/blog\/opencart-event\/","title":{"rendered":"How to use Opencart Events"},"content":{"rendered":"

In Opencart 4, the <\/span>Event System<\/b> is a powerful feature that allows developers to\u00a0 execute specific actions at predefined points in the code execution process. This mechanism is particularly beneficial for extending the platform’s functionality without altering its core files, thereby maintaining the integrity and upgradability of the Opencart system.<\/span><\/p>\n

When a certain event occurs, the event system calls all registered handlers for that event. Each handler can have its own code to handle its event.<\/span><\/p>\n

How Opencart\u00a0 Events Work<\/h2>\n

When an event is triggered, the system automatically calls all registered handlers associated with that event. Each handler can contain custom code to perform the desired actions, such as sending emails, updating records, or integrating with third-party services.<\/span><\/p>\n

Event Types<\/h2>\n

1. Pre-Events:<\/h3>\n

Triggered before a specific action occurs. For example, a pre-event can be triggered before an order is saved, allowing developers to perform custom actions like validating order data.<\/span><\/h3>\n

2. Post-Events:<\/h3>\n

Triggered after a specific action occurs. For example, a post-event can be triggered after a product is edited, allowing developers to perform custom actions like updating related data.<\/span><\/h3>\n

Creating and Registering an Event Listener<\/h2>\n

To use Opencart events, developers need to create an event listener, which is a function or method that responds to a specific event. An event completes the tasks that a controller, a model, a theme override, a language, and a config needs to be achieved in the back-end of the store. Upon startup, the Engine automatically registers triggers, and actions, and sorts orders in both the admin\/controller\/startup\/event.php and catalog\/controller\/startup\/event.php files.<\/span><\/p>\n

Event listeners are registered using the addEvent method from the Event class. The method takes three parameters: the event name, the class\/method to be executed, and the priority of the listener.<\/span><\/p>\n

Key Parameters for `addEvent` Method<\/strong><\/h4>\n