Module Integrations - Magento_Catalog

EAV Framework Integration

Magento_Catalog is tightly coupled with Magento_Eav. Products and Categories are EAV entities, meaning their attributes are stored dynamically in separate tables based on data type.

Integration Points

Entity Types: catalog_product, catalog_category
Attribute Backend: Custom backends for images, prices, tier prices
Attribute Frontend: Custom frontends for display formatting
Attribute Source: Custom sources for dropdowns (status, visibility)

// EAV Entity Type Registration
eav_entity_type
├── entity_type_code: catalog_product
├── entity_model: Magento\Catalog\Model\ResourceModel\Product
├── attribute_model: Magento\Catalog\Model\ResourceModel\Eav\Attribute
└── entity_table: catalog_product_entity

// Attribute Tables
catalog_product_entity_varchar (name, url_key, meta_title)
catalog_product_entity_int (status, visibility)
catalog_product_entity_decimal (price, weight)
catalog_product_entity_datetime (special_from_date)
catalog_product_entity_text (description)

Key Classes

Magento\Catalog\Model\ResourceModel\Product - EAV resource model
Magento\Catalog\Model\ResourceModel\Eav\Attribute - Catalog attribute model
Magento\Catalog\Setup\Patch\Data\* - Attribute creation patches

Inventory (MSI) Integration

Catalog integrates with both legacy CatalogInventory and modern Multi-Source Inventory (MSI) for stock management.

Legacy CatalogInventory

Stock Item: qty, is_in_stock, min_qty, backorders
Stock Status: Real-time salability check
Extension Attributes: stock_item on ProductInterface

// Load stock via extension
$product->getExtensionAttributes()
    ->getStockItem()
    ->getQty();

Multi-Source Inventory (MSI)

Sources: Multiple stock locations
Stocks: Aggregated view per sales channel
Reservations: Pending quantity deductions

// Check salability via MSI
$isSalable = $productSalability
    ->isSalable($sku, $stockId);

Critical: Product Save Stock Race Condition

When saving products via API, stock data may not be properly processed if not included in extension attributes. Always explicitly set stock_item extension attribute when saving via ProductRepository.

Search Integration

Magento_Catalog provides the foundation for product search, which is extended by CatalogSearch and search engine adapters (Elasticsearch, OpenSearch).

Search Indexer Flow

Product save triggers catalogsearch_fulltext indexer
Indexer reads searchable attributes from EAV
Data pushed to Elasticsearch/OpenSearch index
Frontend queries search engine, gets product IDs
Product collection loads matching products

Searchable Attributes

Attributes with is_searchable = 1:

- name, sku, description, short_description
- Custom attributes marked searchable

Filterable Attributes

For layered navigation:

- is_filterable = 1 (category page)
- is_filterable_in_search = 1 (search)

Quote & Sales Integration

Catalog products are added to quotes (carts) and converted to order items during checkout.

Quote Integration

Add to Cart: ProductInterface → QuoteItem
Price Calculation: Uses Catalog pricing rules
Options: Custom options attached to quote item
Stock Reservation: MSI creates reservation

Sales Integration

Order Item: QuoteItem → OrderItem
Product Snapshot: Name, SKU, price frozen at order time
Inventory Deduction: Stock deducted on shipment

// Add product to cart
$quoteRepository->getActiveForCustomer($customerId);
$quote->addProduct($product, $request);
$quoteRepository->save($quote);

// Quote item stores product reference
$item->getProductId();      // catalog_product_entity.entity_id
$item->getSku();            // Frozen at add-to-cart time
$item->getProduct();        // Loads current product data

CMS Integration

Catalog depends on CMS for widgets and category landing pages.

Category CMS Block

Categories can display CMS blocks:

- landing_page attribute
- Static block rendered above/below products
- Design settings from category attributes

Product Widgets

Catalog provides CMS widgets:

- Catalog Product Link
- Catalog Product List
- Catalog New Products List
- Recently Viewed Products

REST & GraphQL APIs

Magento_Catalog exposes comprehensive REST and GraphQL endpoints for headless commerce.

REST API Endpoints

Method	Endpoint	Description
GET	`/V1/products/{sku}`	Get product by SKU
POST	`/V1/products`	Create product
PUT	`/V1/products/{sku}`	Update product
GET	`/V1/categories/{id}`	Get category
GET	`/V1/products/attributes`	List attributes

GraphQL Queries

query GetProduct($sku: String!) {
  products(filter: { sku: { eq: $sku } }) {
    items {
      id
      sku
      name
      price_range {
        minimum_price {
          final_price { value currency }
        }
      }
      media_gallery {
        url
        label
      }
      ... on ConfigurableProduct {
        variants {
          product { sku }
          attributes { code label value_index }
        }
      }
    }
  }
}

query GetCategories {
  categories(filters: { parent_id: { eq: "2" } }) {
    items {
      id
      name
      url_path
      children {
        id
        name
      }
    }
  }
}

API Authentication

REST requires OAuth tokens or Integration tokens. GraphQL supports anonymous (limited) and customer token authentication. Admin operations require admin token with appropriate ACL resources.