How to add an extension attribute into "Customer Address"

Question

I want to manage the "extension attribute" named "example" into "Customer Address" entity.

I've created a new custom module, and I've added the extension attribute into etc/extension_attribute.xml configuration file:

<extension_attributes for="Magento\Customer\Api\Data\AddressInterface">
    <attribute code="example" type="boolean" />
</extension_attributes>

Then, I've deleted the cache and run the magento setup:di:compile command in order to recreate the Dependency Injection cache files. I could see them in the var/generation folder:

./var/generation/Magento/Customer/Api/Data/AddressExtension.php:
public function getExample()
./var/generation/Magento/Customer/Api/Data/AddressExtension.php:
* @param boolean $example ./var/generation/Magento/Customer/Api/Data/AddressExtension.php:
public function setExample($example)
./var/generation/Magento/Customer/Api/Data/AddressExtension.php:
$this->setData('example', $example);
./var/generation/Magento/Customer/Api/Data/AddressExtensionInterface.php: public function getExample();
./var/generation/Magento/Customer/Api/Data/AddressExtensionInterface.php: * @param boolean $example ./var/generation/Magento/Customer/Api/Data/AddressExtensionInterface.php: public function setExample($example);

Now... I want to intercept \Magento\Customer\Api\AddressRepositoryInterface::getById() (after) action. I've added a new plugin into etc/di.xml configuration file:

<type name="Magento\Customer\Model\ResourceModel\AddressRepository">
    <plugin name="your_plugin_name"
            type="your_name\module_name\Plugin\CustomerAddressRepository"
            sortOrder="1000" />
</type>

and I've created the related plugin:

class CustomerAddressRepository
{
    public function afterGetById(
        $subject,
        \Magento\Customer\Model\Data\Address $result
    ) {
        // my code...
    }
}

but when I try to get the new extension attribute example, the $result->getExtensionAttributes() function always returns a null value.

I've already implemented extension attributes into the Magento_Checkout module with success. I've already read similar question like this. but I haven't found any solution to my problem.

Have I forgotten an implementation step?

Answer 1

This is just a guess:

You could try to plug in after to \Magento\Customer\Api\AddressRepositoryInterface::getById()

and as far as I know, $result->getExtensionAttributes() may return null - If it does, just take a \Magento\Framework\Api\ExtensionAttributesFactory and then use $this->extAttribFactory->create();