How i can work with extension attributes using collection?

Question

Hello i have to add extension attributes to Magento\Catalog\Api\Data\ProductInterface

So i added this one to extension_attrributes.xml:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
    <extension_attributes for="Magento\Catalog\Api\Data\ProductInterface">
        <attribute code="custom_attribute" type="int"/>
    </extension_attributes>
</config>

And to di.xml added:

<type name="Magento\Framework\EntityManager\Operation\ExtensionPool">
        <arguments>
            <argument name="extensionActions" xsi:type="array">
                <item name="Magento\Catalog\Api\Data\ProductInterface" xsi:type="array">
                    <item name="read" xsi:type="array">
                        <item name="customAttributeReader" xsi:type="string">Vendor\Custom\Model\Product\CustomAttribute\ReadHandler</item>
                    </item>
                    <item name="create" xsi:type="array">
                        <item name="customAttributeCreator" xsi:type="string">Vendor\Custom\Model\Product\CustomAttribute\SaveHandler</item>

                    </item>
                    <item name="update" xsi:type="array">
                        <item name="customAttributeSaver" xsi:type="string">Vendor\Custom\Model\Product\CustomAttribute\SaveHandler</item>
                    </item>
                </item>
            </argument>
        </arguments>
    </type>

So it`s work fine. When i get product entity using ProductRepository or load() function in Product model, all my extension attributes loads successful. But i have some issue when i work with Collection:

When i do something like:

$productCollection->addFieldToFilter('custom_attribute', 2);

My code don't wok and it's expected because my model not contains this attribute.

So i have a question. How i can filter by my extension attribute using collection ?

Also if i do:

$productCollection->getFirstItem()->getExtensionAttributes()

I get empty array.

So i need your help. I'll be very grateful!!!

Answer 1

I added extension attributes with repository plugin. And works fine. But only with repository, so I'm also looking for solution.