Add custom attributes to any model

[marvincaspar]

I want to add custom attributes for any model, in this example I use the shipment

Steps to reproduce

• Install Magento v2.0.2
• Override for example the shipment class and set the available custom attributes codes with getCustomAttributesCodes()

di.xml

<preference for="Magento\Sales\Model\Order\Shipment" type="My\Namespace\Model\Order\SalesShipment"/>

SalesShipment.php

<?php

namespace My\Namespace\Model\Order;

class SalesShipment extends \Magento\Sales\Model\Order\Shipment
{
    /**
     * @param \Magento\Framework\Model\Context $context
     * @param \Magento\Framework\Registry $registry
     * @param \Magento\Framework\Api\ExtensionAttributesFactory $extensionFactory
     * @param \Magento\Framework\Api\AttributeValueFactory $customAttributeFactory
     * @param \Magento\Sales\Model\ResourceModel\Order\Shipment\Item\CollectionFactory $shipmentItemCollectionFactory
     * @param \Magento\Sales\Model\ResourceModel\Order\Shipment\Track\CollectionFactory $trackCollectionFactory
     * @param \Magento\Sales\Model\Order\Shipment\CommentFactory $commentFactory
     * @param \Magento\Sales\Model\ResourceModel\Order\Shipment\Comment\CollectionFactory $commentCollectionFactory
     * @param \Magento\Sales\Api\OrderRepositoryInterface $orderRepository
     * @param \Magento\Framework\Model\ResourceModel\AbstractResource $resource
     * @param \Magento\Framework\Data\Collection\AbstractDb $resourceCollection
     * @param array $data
     * @SuppressWarnings(PHPMD.ExcessiveParameterList)
     */
    public function __construct(
        \Magento\Framework\Model\Context $context,
        \Magento\Framework\Registry $registry,
        \Magento\Framework\Api\ExtensionAttributesFactory $extensionFactory,
        \Magento\Framework\Api\AttributeValueFactory $customAttributeFactory,
        \Magento\Sales\Model\ResourceModel\Order\Shipment\Item\CollectionFactory $shipmentItemCollectionFactory,
        \Magento\Sales\Model\ResourceModel\Order\Shipment\Track\CollectionFactory $trackCollectionFactory,
        \Magento\Sales\Model\Order\Shipment\CommentFactory $commentFactory,
        \Magento\Sales\Model\ResourceModel\Order\Shipment\Comment\CollectionFactory $commentCollectionFactory,
        \Magento\Sales\Api\OrderRepositoryInterface $orderRepository,
        \Magento\Framework\Model\ResourceModel\AbstractResource $resource = null,
        \Magento\Framework\Data\Collection\AbstractDb $resourceCollection = null,
        array $data = []
    )
    {
        parent::__construct(
            $context,
            $registry,
            $extensionFactory,
            $customAttributeFactory,
            $shipmentItemCollectionFactory,
            $trackCollectionFactory,
            $commentFactory,
            $commentCollectionFactory,
            $orderRepository,
            $resource,
            $resourceCollection,
            $data
        );
    }

    /**
     * {@inheritdoc}
     */
    protected function getCustomAttributesCodes()
    {
        return [
            "house_number"
        ];
    }
}

• Call api method, e.g. to create a shipment with the following data

{  
  "shipment":{  
    "custom_attributes": [
       {
        "attribute_code": "house_number",
        "value": "123"
       }
    ],
    ...
  }
}

Expected result

1. The custom attributes are stored
2. Load a shipment and call getCustomAttributes() should get the custom attributes
3. The api get call returns the custom attributes

{
   "increment_id": "000000001",
   "custom_attributes": [   {
      "attribute_code": "url_key",
      "value": "12345678"
   }],
  ...
}

Actual result

1. $newShipment = $shipment->save() includes the custom attributes
2. If I load the shipment object and call getCustomAttributes() I get an empty array

{
   "increment_id": "000000001",
  ...
}

[alena-marchenko]

Hi Marvin,

We've created MAGETWO-52315 internal ticket regarding this issue.
Thank you.

[SantyagoSeaman]

Hello!

Unfortunately, you can't add custom attributes to any model without implementing backend logic for storing and loading appropriate data. For example, it's already implemented in Catalog and Customer modules and the entities like Product, Category or Customer can be easily extended with new attributes according to a number of articles:
https://www.atwix.com/magento/adding-attribute-programatically-magento2/
https://maxyek.wordpress.com/2015/10/22/building-magento-2-extension-customergrid/
http://www.clounce.com/magento/magento-2-customer-attributes

The most modern way to add custom attributes in Magento 2 is the Extension Attributes approach.
Some basic documentation: http://devdocs.magento.com/guides/v2.0/extension-dev-guide/attributes.html
Example: http://oyenetwork.com/articles/magento2-devliery-date-module-creation-from-scratch/

If you have any questions regarding implementation, please feel free to ask on our forum.