How to add new parameters to a core model in Magento2?

Question

I am trying to develop a Module to support saving card_id for a Gateway handling such functionality. So basically you send the card information in frontend, the gateway returns a token then you call the gateway API in the server and it returns a card_id. A customer can have 'n' cards so I am planning to create a schema table 'cards' which relates to customers the same way as addresses do.

My question is how can I add another array to the customer object. The array should be similar to that of customer_addresses.

I have set my extension_attributes.xml like this:

<?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\CustomerInterface">
        <attribute code="gateway_card_id" type="text">
            <join reference_table="card_entity"
                reference_field="user_id"
                join_on_field="parent_id"
            >
            <field>group_id</field>
            </join>
        </attribute>
    </extension_attributes>
</config>

The table card_entity already exists too.

The problem is I am not seeing any extension attribute when I call the API /customers/me

Answer 1

You need declare extension attribute and use plugin on order repository to populate/save card entities. You can review Bundle Module extension attribute declaration as good example of such case implementation.