Magento 2 Events and Observers

Magento 2 Events and Observers let you hook into Magento’s execution flow without modifying core code. This allows developers to perform actions when specific events happen, making the system highly extensible.

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🔄 What are Events and Observers?

• Events: Actions that happen during Magento’s execution (e.g., customer login).
• Observers: Classes that listen to events and respond with custom logic.

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📍 Common Use Cases

• Send an email after order placement
• Log data on customer login
• Modify product data before save

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🔧 Create a Custom Observer

Step 1: Declare Events in events.xml

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Step 2: Create the Observer Class

<?php
namespace Vendor\Module\Observer;

use Magento\Framework\Event\Observer;
use Magento\Framework\Event\ObserverInterface;

class CustomerLoginObserver implements ObserverInterface
{
    public function execute(Observer $observer)
    {
        $customer = $observer->getEvent()->getCustomer();
        // Custom logic here
        // Example: Log customer email
        $writer = new \Zend_Log_Writer_Stream(BP . '/var/log/customer_login.log');
        $logger = new \Zend_Log();
        $logger->addWriter($writer);
        $logger->info('Customer Logged In: ' . $customer->getEmail());
    }
}
  

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Step 3: Enable & Test

1. Run: php bin/magento setup:upgrade
2. Run: php bin/magento cache:flush
3. Log in as a customer and check var/log/customer_login.log

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🧩 Popular Magento Events

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✅ Best Practices

• Use observers only when no plugin or DI method fits
• Use unique observer names
• Keep observer logic simple and efficient

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🧠 Summary

• Events let you hook into Magento without overriding
• Observers respond to specific events with custom logic
• Easy to extend Magento functionality safely