Products, categories, customers and orders

Products, categories, customers and orders are stored in dozens of related core tables. You do not read them with SQL queries: every kind of data has a repository — an interface with the same get, getList and save methods as the review repository. These interfaces do not change when Magento is updated.

Core repositories

A repository is requested in the constructor of your class. Modules whose interfaces you use are listed in the sequence section of module.xml.

A product by SKU

Create a class in the module that gathers information about the shop:

// app/code/Acme/Hello/Model/ShopInfo.php
namespace Acme\Hello\Model;
 
use Magento\Catalog\Api\ProductRepositoryInterface;
 
class ShopInfo
{
    public function __construct(private ProductRepositoryInterface $productRepository) {}
 
    public function productName(string $sku): string
    {
        $product = $this->productRepository->get($sku);
 
        return (string) $product->getName();
    }
}

The get() method finds a product by its SKU, and getById() by its ID. If the product does not exist, both throw a NoSuchEntityException.

Using it

Let's call the class from the Status action of the earlier lessons:

// app/code/Acme/Hello/Controller/Index/Status.php
public function execute(): ResultInterface
{
    return $this->resultFactory->create(ResultFactory::TYPE_JSON)
        ->setData(['name' => $this->shopInfo->productName('24-MB01')]);
}

Add ShopInfo to the action constructor, clear the generated folder and open /hello/index/status. With the sample data installed the response is {"name":"Joust Duffle Bag"}.

A list of products

Search conditions are assembled by SearchCriteriaBuilder — the same way as for reviews:

// app/code/Acme/Hello/Model/ShopInfo.php
public function cheapProducts(): array
{
    $criteria = $this->criteriaBuilder
        ->addFilter('price', 50, 'lt')
        ->setPageSize(10)
        ->create();
 
    return $this->productRepository->getList($criteria)->getItems();
}

The method returns up to ten products cheaper than 50. Each one has getSku(), getName(), getPrice(). The Magento\Framework\Api\SearchCriteriaBuilder object is added to the constructor.

Changing a product

// app/code/Acme/Hello/Model/ShopInfo.php
public function setPrice(string $sku, float $price): void
{
    $product = $this->productRepository->get($sku);
    $product->setPrice($price);
 
    $this->productRepository->save($product);
}

The product is saved with all core checks, and indexes and the cache are refreshed automatically.

Category, customer, order

// app/code/Acme/Hello/Model/ShopInfo.php
public function summary(int $categoryId, string $email, int $orderId): array
{
    $category = $this->categoryRepository->get($categoryId);
    $customer = $this->customerRepository->get($email);
    $order = $this->orderRepository->get($orderId);
 
    return [
        'category' => $category->getName(),
        'customer' => $customer->getFirstname() . ' ' . $customer->getLastname(),
        'order' => $order->getIncrementId(),
        'total' => $order->getGrandTotal(),
    ];
}

A category and an order are found by ID, a customer by email address or through getById(). The getIncrementId() method returns the order number the customer sees, and getGrandTotal() the final amount.

A customer's orders

// app/code/Acme/Hello/Model/ShopInfo.php
public function ordersOf(string $email): array
{
    $criteria = $this->criteriaBuilder
        ->addFilter('customer_email', $email)
        ->create();
 
    return $this->orderRepository->getList($criteria)->getItems();
}

The method returns all orders with the given email address.

Common mistake

A repository is called in a loop: for a hundred reviews $this->productRepository->getById() runs a hundred times. Every call loads a whole product with all its attributes, and the page takes several seconds to open. Collect the IDs and fetch the products with a single getList() call using the in condition on the entity_id field.