How to Add Extension Attribute to Order in Magento 2

There are six simple steps to add the extension attribute to order in Magento 2:

Step 1: Let’s create the extension_attributes.xml file

First and foremost, you need to declare your extension attributes in one XML file:

<!-- etc/extension_attributes.xml -->	
<?xml version="1.0"?>	
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">	
    <extension_attributes for="Magento\Sales\Api\Data\OrderInterface">	
	<attribute code="tigren_attribute" type="Tigren\Example\Api\Data\TigrenAttributeInterface" />
    </extension_attributes>	
</config>	

By this way, you are extending your Sales Order Interface with an attribute. It can be accessible via $order->getExtensionAttributes()->getFoomanAttribute().

Step 2: Create an interface for your extension attribute

<?php		
		
namespace Tigren\Example\Api\Data;		
		
interface TigrenAttributeInterface		
{		
    const VALUE = 'value';		
		
    /**		
     * Return value.		
     *		
     * @return string|null 		
     */		
    public function getValue();		
		
    /**		
     * Set value.		
     *		
     * @param string|null $value		
     * @return $this		
     */		
    public function setValue($value);		
}		

Step 3: Create a concrete class for the interface that you created

<?php		
		
namespace Tigren\Example\Model;		
		
class TigrenAttribute implements \Tigren\Example\Api\Data\FoomanAttributeInterface		
{		
    /**		
     * {@inheritdoc}		
     */		
    public function getValue()		
    {		
	return $this->getData(self::VALUE);	
    }		
		
    /**		
     * {@inheritdoc}		
     */		
    public function setValue($value)		
    {		
	return $this->setData(self::VALUE, $value);	
    }		
}		

The interface \Magento\Sales\Api\Data\OrderExtensionInterface is generated by Magento, either on the development mode or the compilation process. The code generation happens via \Magento\Framework\Code\Generator for any interface which cannot be loaded. It will read our XML configuration and create an interface which includes a getter and setter for tigren_attribute.

Step 4: Create a plugin to save and retrieve the new attributes

The Magento 2 plugin is built here with the purpose of adding extra behavior to the current code by executing certain code. Moreover, the plugin will enable you to execute code before, after or around any public method.

<!-- etc/di.xml -->		
<?xml version="1.0"?>		
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">		
    <type name="Magento\Sales\Api\OrderRepositoryInterface">		
	<plugin name="save_tigren_attribute" type="Tigren\Example\Plugin\OrderSave"/>	
	<plugin name="get_tigren_attribute" type="Tigren\Example\Plugin\OrderGet"/>	
    </type>		
</config>			

As you can see, we have attached the OrderSave and OrderGet plugins to the core OrderRepositoryInterface. Now, it’s necessary to implement a specific logic for those classes.

Step 5: Save the order

You must find out a way to save your new attribute somewhere to the database.

<?php		
		
namespace Tigren\Example\Plugin;		
		
use Magento\Framework\Exception\CouldNotSaveException;		
		
class OrderSave		
{		
		
...		
		
    public function afterSave(		
	\Magento\Sales\Api\OrderRepositoryInterface $subject,	
	\Magento\Sales\Api\Data\OrderInterface $resultOrder	
    ) {		
	$resultOrder = $this->saveTigrenAttribute($resultOrder);	
		
	return $resultOrder;	
    }		
		
    private function saveTigrenAttribute(\Magento\Sales\Api\Data\OrderInterface $order)		
    {		
	$extensionAttributes = $order->getExtensionAttributes();	
	if (	
	    null !== $extensionAttributes &&	
	    null !== $extensionAttributes->getTigrenAttribute()	
	) {	
	    $tigrenAttributeValue = $extensionAttributes->getTigrenAttribute()->getValue();	
	    try {	
	        // The actual implementation of the repository is omitted	
	        // but it is where you would save to the database (or any other persistent storage)	
	        $this->tigrenExampleRepository->save($order->getEntityId(), $tigrenAttributeValue);	
	    } catch (\Exception $e) {	
	        throw new CouldNotSaveException(	
	            __('Could not add attribute to order: "%1"', $e->getMessage()),	
	            $e	
	        );	
	    }	
	}	
	return $order;	
    }		
}		
		

Step 6: Order Get

<?php		
		
namespace Tigren\Example\Plugin;		
		
class OrderGet		
{		
		
...  		
		
    public function afterGet(		
	\Magento\Sales\Api\OrderRepositoryInterface $subject,	
	\Magento\Sales\Api\Data\OrderInterface $resultOrder	
    ) {		
	$resultOrder = $this->getTigrenAttribute($resultOrder);	
		
	return $resultOrder;	
    }		
		
    private function getTigrenAttribute(\Magento\Sales\Api\Data\OrderInterface $order)		
    {		
		
	try {	
	    // The actual implementation of the repository is omitted	
	    // but it is where you would load your value from the database (or any other persistent storage)	
	    $tigrenAttributeValue = $this->tigrenExampleRepository->get($order->getEntityId());	
	} catch (NoSuchEntityException $e) {	
	    return $order;	
	}	
		
	$extensionAttributes = $order->getExtensionAttributes();	
	$orderExtension = $extensionAttributes ? $extensionAttributes : $this->orderExtensionFactory->create();	
	$tigrenAttribute = $this->tigrenAttributeFactory->create();	
	$tigrenAttribute->setValue($tigrenAttributeValue);	
	$orderExtension->setTigrenAttribute($tigrenAttribute);	
	$order->setExtensionAttributes($orderExtension);	
		
	return $order;	
    }		
}		

• IMPORTANCE: It’s worth noting that in order for the Extension Attribute to work as expected, it’s fundamental to query the entity for existing extension_attributes via $order->getExtensionAttributes() before utilizing the extension attribute factory to create a new one. In case that you bypass this test, you might eliminate any previously set extension attributes on the entity.

We have shown you an easy instruction to add the extension attribute in Magento 2. If you have any problem when following the guide, please leave a comment below.