Return custom db fields via graphql resolvers

Question

I've added custom fields to sales_order

Now I want to return them in customerOrders GraphQL query as a value from database.

How can I do it without fetching the order from database again in Resolver class?

Answer 1

It's pretty simple - just add your field to the graphql in custom module and add a resolver which could use already loaded order model to get desired data.

etc/schema.graphqls

type CustomerOrder {
    my_custom_field: String
    @resolver(class: "MageWorx\\ExtendedCartGraphQl\\Model\\Resolver\\OrderCustomField")
}

Model/Resolver/OrderCustomField.php

<?php
/**
 * Copyright © MageWorx. All rights reserved.
 * See LICENSE.txt for license details.
 */
declare(strict_types=1);

namespace MageWorx\ExtendedCartGraphQl\Model\Resolver;

use Magento\Framework\Exception\LocalizedException;
use Magento\Framework\GraphQl\Config\Element\Field;
use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;

class OrderCustomField implements \Magento\Framework\GraphQl\Query\ResolverInterface
{
    /**
     * @inheritDoc
     */
    public function resolve(Field $field, $context, ResolveInfo $info, array $value = null, array $args = null)
    {
        if (!isset($value['model'])) {
            throw new LocalizedException(__('"model" value should be specified'));
        }
        /** @var \Magento\Sales\Api\Data\OrderInterface $order */
        $order = $value['model'];

        return (string)$order->getData('your_custom_field');
    }
}

Here is my example module on GitHub. I used the customer query with orders because the customerOrders query is deprecated. Here is example of request:

{
    customer {
        orders {
            total_count
            items
            {
                    id
                    order_date
                    my_custom_field
            }
        }
    }
}

and response:

{
    "data": {
        "customer": {
            "orders": {
                "total_count": 7,
                "items": [
                    {
                        "id": "MTc=",
                        "order_date": "2022-05-01 18:11:38",
                        "my_custom_field": ""
                    },
                    {
                        "id": "MTk=",
                        "order_date": "2022-05-02 09:35:00",
                        "my_custom_field": ""
                    },
                    {
                        "id": "MjA=",
                        "order_date": "2022-05-02 19:29:30",
                        "my_custom_field": ""
                    },
                    {
                        "id": "MjE=",
                        "order_date": "2022-05-02 19:34:42",
                        "my_custom_field": ""
                    },
                    {
                        "id": "MjI=",
                        "order_date": "2022-05-03 08:32:20",
                        "my_custom_field": ""
                    },
                    {
                        "id": "MjU=",
                        "order_date": "2022-05-05 17:13:03",
                        "my_custom_field": ""
                    },
                    {
                        "id": "MzA=",
                        "order_date": "2022-05-28 12:41:00",
                        "my_custom_field": ""
                    }
                ]
            }
        }
    }
}