Fetching Data from "Entity Selection" Custom Field

Overview

If you set up a custom field with an entity selection in the Administration, you may need a data resolver to resolve the ID to an entity object.

Prerequisites

This guide will not explain how to create custom field in general, so head over to the official guide about custom field to learn this first.

Fetching data

In this example we assume that we already set up a custom field called custom_linked_product, which is assigned to the products entity. The type of the custom field custom_linked_product is also a product.

If you now update a product in the Administration and select a value for custom_linked_product only the id of the selected product entity gets store in the custom field.

To resolve the id and getting access to the product we have linked here, we can create a ProductSubscriber which listens to the ProductEvents::PRODUCT_LOADED_EVENT. The event will be triggered, when the associated main product will be loaded. So we can easily resolve the id in the custom field.

Lets create a ProductSubscriber first which will listen to the ProductEvents::PRODUCT_LOADED_EVENT.

// <plugin root>/src/Subscriber/ProductSubscriber.php
<?php declare(strict_types=1);

namespace Swag\BasicExample\Subscriber;

use Shopware\Core\Framework\DataAbstractionLayer\Event\EntityLoadedEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Shopware\Core\Content\Product\ProductEvents;

class ProductSubscriber implements EventSubscriberInterface
{
    public static function getSubscribedEvents(): array
    {
        return [
            ProductEvents::PRODUCT_LOADED_EVENT => 'onProductLoaded'
        ];
    }

    public function onProductLoaded(EntityLoadedEvent $event): void
    {
    }
}

For this subscriber to work we need to register it in the service container via the services.xml file:

// <plugin root>/src/Resources/config/services.xml
<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="Swag\BasicExample\Subscriber\ProductSubscriber">
            <tag name="kernel.event_subscriber"/>
        </service>
    </services>
</container>

Now our ProductSubscriber should be called every time a product is loaded, so we can resolve the custom field custom_linked_product.

// <plugin root>/src/Subscriber/ProductSubscriber.php
<?php declare(strict_types=1);

namespace Swag\BasicExample\Subscriber;

use Shopware\Core\Framework\DataAbstractionLayer\Event\EntityLoadedEvent;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Shopware\Core\Content\Product\ProductEvents;

class ProductSubscriber implements EventSubscriberInterface
{
    public static function getSubscribedEvents(): array
    {
        return [
            ProductEvents::PRODUCT_LOADED_EVENT => 'onProductLoaded'
        ];
    }

    public function onProductLoaded(EntityLoadedEvent $event): void
    {

        // loop through all loaded product      
        /** @var ProductEntity $productEntity */
        foreach ($event->getEntities() as $productEntity) {
            $customFields = $productEntity->getCustomFields();

            // loop through each product's custom fields
            foreach($customFields as $name => $value) {
                if ($name !== 'custom_linked_product' || empty($value)) {
                    continue;
                }

               // resolve the $value here
            }

            $productEntity->setCustomFields($customFields);
        }
    }
}

Inside the onProductLoaded method we can get access to the loaded product entities by calling $event->getEntities(). Now for every product we look for our custom_linked_product custom field.

But, how we can load the linked product by its id if the custom field was set? We have to inject the product repository to achieve it.

First we update the services.xml and inject the product repository.

// <plugin root>/src/Resources/config/services.xml
<?xml version="1.0" ?>

<container xmlns="http://symfony.com/schema/dic/services"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd">

    <services>
        <service id="Swag\BasicExample\Subscriber\ProductSubscriber">
            <argument type="service" id="product.repository"/>
            <tag name="kernel.event_subscriber"/>
        </service>
    </services>
</container>

Now we can use the product repository in our subscriber.

// <plugin root>/src/Subscriber/ProductSubscriber.php
<?php declare(strict_types=1);

namespace Swag\BasicExample\Subscriber;

use Shopware\Core\Content\Product\ProductEntity;
use Shopware\Core\Framework\DataAbstractionLayer\EntityRepository;
use Shopware\Core\Framework\DataAbstractionLayer\Event\EntityLoadedEvent;
use Shopware\Core\Framework\DataAbstractionLayer\Search\Criteria;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Shopware\Core\Content\Product\ProductEvents;

class ProductSubscriber implements EventSubscriberInterface
{
    private EntityRepository $productRepository;

    public function __construct(EntityRepository $productRepository) 
    {
        $this->productRepository = $productRepository;
    }

   //...
}

As you can see, the product repository was injected and is now available to the ProductRepository. The last step is to resolve the custom_linked_product value inside the onProductLoaded method.

Let's have a look at the final implementation of the subscriber.

// <plugin root>/src/Subscriber/ProductSubscriber.php
<?php declare(strict_types=1);

namespace Swag\BasicExample\Subscriber;

use Shopware\Core\Content\Product\ProductEntity;
use Shopware\Core\Framework\DataAbstractionLayer\EntityRepository;
use Shopware\Core\Framework\DataAbstractionLayer\Event\EntityLoadedEvent;
use Shopware\Core\Framework\DataAbstractionLayer\Search\Criteria;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Shopware\Core\Content\Product\ProductEvents;

class ProductSubscriber implements EventSubscriberInterface
{
    private EntityRepository $productRepository;

    public function __construct(EntityRepository $productRepository) 
    {
        $this->productRepository = $productRepository;
    }

    public static function getSubscribedEvents(): array
    {
        return [
            ProductEvents::PRODUCT_LOADED_EVENT => 'onProductLoaded'
        ];
    }

    public function onProductLoaded(EntityLoadedEvent $event): void
    {
        // extract all ids of our custom field
        $ids = array_map(function (ProductEntity $entity) {
            return $entity->getCustomFields()['custom_demo_test'] ?? null;
        }, $event->getEntities());

        // filter empty ids
        $ids = array_filter($ids);

        // load all products in one request instead of one request per product (big performance boost)
        $products = $this->productRepository->search(new Criteria($ids), $event->getContext());

        /** @var ProductEntity $entity */
        foreach ($event->getEntities() as $entity) {
            // check if the custom field is set
            if (!$id = $entity->getCustomFields()['custom_demo_test'] ?? null) {
                continue;
            }

            // add the product to the entity as entity extension
            $entity->addExtension('my_custom_demo_product', $products->get($id));
        }
    }
}