How to call an observer from custom module: Magento 2

Question

I built a custom module which has a custom observer OrderSaveAfter.php. How can I call any function inside the custom observer from another custom code ?

Answer 1

you can use an event called checkout_onepage_controller_success_action

Please follow the below steps

Step 1: app/code/Ewall/Paytrade/etc/frontend/events.xml

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Event/etc/events.xsd">
       <event name="checkout_onepage_controller_success_action">
           <observer name="Ewall_Paytrade_After_Place_Order_Success" instance="Namespace\Module\Observer\AfterOrder"  />
       </event>
    </config>

Step 2:

<?php
 namespace Ewall\Paytrade\Observer;
 use Magento\Framework\Event\ObserverInterface;
 use Magento\Framework\App\RequestInterface;
 use Magento\Sales\Api\OrderRepositoryInterface;
 use Magento\Customer\Model\Session;
class PlaceOrderSuccess implements ObserverInterface
{ 

    protected $orderRepository;
    protected $_session;

    public function __construct(  
    OrderRepositoryInterface $OrderRepositoryInterface,
    \Magento\Customer\Model\Session $session
    ) {
        $this->orderRepository = $OrderRepositoryInterface;
        $this->_session = $session;

    }

    public function execute(\Magento\Framework\Event\Observer $observer) 
    {

           $writer = new \Zend\Log\Writer\Stream(BP.'/var/log/TradeorderSuccess.log');
           $logger = new \Zend\Log\Logger();
           $logger->addWriter($writer);            

           $order_ids = $observer->getEvent()->getOrderIds()[0];
           $order = $this->orderRepository->get($order_ids);           
           $order_id = $order->getIncrementId();               

          foreach ($order->getAllVisibleItems() as $item)
          {
                $logger->info("xxxxxxxxxxxxxxxxxx===>".$item->getName());
           } 

          $order->save();
          $logger->info("saved");
    }


}

Step 3: after did the changes use di.compile and clear cache & pagecache and and check the same.

Answer 2

At the end, your observer is a class. So, I believe you could try to inject it in any other class constructor, and so call any method you want

<?php
namespace YourNamespace\YourModuleName\Observer;
use Magento\Framework\Event\ObserverInterface;

class YourObserver implements ObserverInterface
{
...

So, in any of your classes

protected $_observer;

public function __construct(
    \YourNamespace\YourModuleName\Observer\YourObserver $observer
) {
    $this->_observer = $observer;
}

Although, considering you cannot define which concrete method to be executed in your events xml file (as we did in Magento 1), I would say this could be not a good practice

I can't find any reason why you'd have some public methods in your observer. In that case maybe you'll want to move it to a helper or any other class in your custom module, and then inject that class in observer's constructor if you need to call them during execute() method

Answer 3

If you have a function in your observer that needs to be used in other parts of your code, a better practice would be to move that function into a helper class or a model, depending on what the function does.

Example :

1. Create a helper class in your module:

namespace Vendor\Module\Helper;

class Data extends \Magento\Framework\App\Helper\AbstractHelper
{
    public function yourFunction()
    {
        // Your function code here
    }
}

2. Then, you can call this function from anywhere in your code like this:

Here's how you could do this in a controller:

namespace Vendor\Module\Controller\Index;

class Index extends \Magento\Framework\App\Action\Action
{
    protected $_helper;

    public function __construct(
        \Magento\Framework\App\Action\Context $context,
        \Vendor\Module\Helper\Data $helper
    ) {
        $this->_helper = $helper;
        parent::__construct($context);
    }

    public function execute()
    {
        $this->_helper->yourFunction();
    }
}

This way, your function is available to be used anywhere in your code, and you're following Magento's best practices.