Add attributes to the Order API shipping_address

Question

I am calling this endpoint:

http://localhost/index.php/rest/V1/orders/<myId>

And I want to have 2 customer address attributes inside the response (-> billing_address). In order to get there I created extension_attributes.xml and added this content:

<?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\Customer\Api\Data\AddressInterface">
        <attribute code="my_attribute_1" type="string" />
        <attribute code="my_attribute_2" type="string" />
    </extension_attributes>
</config>

However, I do not see the response contain the respective Key-Value data.

To visualize, I want to have the attributes here:

Answer 1

Okay, after stepping trough some other places, I've eventually identified how I can add the attributes to a additional key called extension_attributes inside billing_address. Not exactly what I was looking for, but a good start.

My extension_attributes.xml looks like this now:

<?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\OrderAddressExtensionInterface">
        <attribute code="my_attr_1" type="string" />
        <attribute code="my_attr_2" type="string" />
    </extension_attributes>
</config>

Also, I've created in my module etc/webapi_rest/di.xml with this content:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="\Magento\Sales\Model\OrderRepository">
        <plugin name="order_repository" type="SEEC\RestApi\Plugin\Magento\Sales\Model\OrderRepository" disabled="false" sortOrder="200" />
    </type>
</config>

And created this file to attach the data properly:

<?php

namespace SEEC\RestApi\Plugin\Magento\Sales\Model;

use Magento\Sales\Api\Data\OrderInterface;
use Magento\Sales\Model\OrderRepository as ModelOrderRepository;

class OrderRepository
{

    /**
     * @param ModelOrderRepository $orderRepository
     * @param OrderInterface $order
     * @return OrderInterface
     */
    public function afterGet(
        ModelOrderRepository $orderRepository,
        OrderInterface $order
    ) {
        $billingAddress = $order->getBillingAddress();
        $billingAddressExtensionAttributes = (null !== $billingAddress->getExtensionAttributes())
            ? $billingAddress->getExtensionAttributes()
            : '';

        $billingAddressExtensionAttributes->setMyAttr1($billingAddress->getMyAttr1());
        $billingAddressExtensionAttributes->setMyAttr2($billingAddress->getMyAttr2());

        $billingAddress->setExtensionAttributes($billingAddressExtensionAttributes);

        if (!$order->getIsVirtual()) {
            $shippingAddress = $order->getShippingAddress();
            $shippingAddressExtensionAttributes = (null!== $shippingAddress->getExtensionAttributes())
                ? $shippingAddress->getExtensionAttributes()
                : '';

            $shippingAddressExtensionAttributes->setMyAttr1($shippingAddress->getMyAttr1());
            $shippingAddressExtensionAttributes->setMyAttr2($shippingAddress->getMyAttr2());
            $shippingAddress->setExtensionAttributes($shippingAddressExtensionAttributes);
        }

        return $order;
    }
}