Listen to an event with an observer in Magento

Let’s say we wanted to listen for this macademy_blog_post_detail_view event and carry out an action on it, such as outputting the page response to a log file. We can do this with an observer.

Observers are the other half of an event, and allow you to carry out an action that requires no response by the code that has dispatched an event. Observers work from the relationship between two files: an XML file and a related PHP class that is the observer. The XML defines which event you’d like to listen to, and it references the PHP class that is observing this event:

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