Shopping: Support pagination in API

includes/Interfaces/Product_Query.php

@@ -26,7 +26,6 @@
 
 namespace Google\Web_Stories\Interfaces;
 
-use Google\Web_Stories\Shopping\Product;
 use WP_Error;
 
 /**
@@ -39,9 +38,11 @@ interface Product_Query {
 	 * @since 1.21.0
 	 *
 	 * @param string $search_term Search term.
-	 * @param string $orderby Sort collection by product attribute.
-	 * @param string $order Order sort attribute ascending or descending.
-	 * @return Product[]|WP_Error
+	 * @param int    $page        Number of page for paginated requests.
+	 * @param int    $per_page    Number of products to be fetched.
+	 * @param string $orderby     Sort collection by product attribute.
+	 * @param string $order       Order sort attribute ascending or descending.
+	 * @return array|WP_Error
 	 */
-	public function get_search( string $search_term, string $orderby, string $order);
+	public function get_search( string $search_term, int $page = 1, int $per_page = 100, string $orderby = 'date', string $order = 'desc' );
 }

includes/REST_API/Products_Controller.php

@@ -140,6 +140,8 @@ public function get_items_permissions_check( $request ) {
 	/**
 	 * Retrieves all products.
 	 *
+	 * @SuppressWarnings(PHPMD.NPathComplexity)
+	 *
 	 * @since 1.20.0
 	 *
 	 * @param WP_REST_Request $request Full details about the request.
@@ -168,34 +170,56 @@ public function get_items( $request ) {
 		 * @var string $search_term
 		 */
 		$search_term = ! empty( $request['search'] ) ? $request['search'] : '';
-		
+
 		/**
 		 * Request context.
 		 *
 		 * @var string $orderby
 		 */
 		$orderby = ! empty( $request['orderby'] ) ? $request['orderby'] : 'date';
 
+		/**
+		 * Request context.
+		 *
+		 * @var int $page
+		 */
+		$page = ! empty( $request['page'] ) ? $request['page'] : 1;
+
+		/**
+		 * Request context.
+		 *
+		 * @var int $per_page
+		 */
+		$per_page = ! empty( $request['per_page'] ) ? $request['per_page'] : 100;
+
 		/**
 		 * Request context.
 		 *
 		 * @var string $order
 		 */
 		$order = ! empty( $request['order'] ) ? $request['order'] : 'desc';
-
-
-		$query_result = $query->get_search( $search_term, $orderby, $order );
+
+		$query_result = $query->get_search( $search_term, $page, $per_page, $orderby, $order );
 		if ( is_wp_error( $query_result ) ) {
 			return $query_result;
 		}
 
 		$products = [];
-		foreach ( $query_result as $product ) {
+		foreach ( $query_result['products'] as $product ) {
 			$data       = $this->prepare_item_for_response( $product, $request );
 			$products[] = $this->prepare_response_for_collection( $data );
 		}
 
-		return rest_ensure_response( $products );
+		/**
+		 * Response object.
+		 *
+		 * @var WP_REST_Response $response
+		 */
+		$response = rest_ensure_response( $products );
+
+		$response->header( 'X-WP-HasNextPage', (string) $query_result['has_next_page'] );
+
+		return $response;
 	}
 
 	/**
@@ -420,6 +444,8 @@ public function get_item_schema(): array {
 	public function get_collection_params(): array {
 		$query_params = parent::get_collection_params();
 
+		$query_params['per_page']['default'] = 100;
+
 		$query_params['orderby'] = [
 			'description' => __( 'Sort collection by product attribute.', 'web-stories' ),
 			'type'        => 'string',

includes/Shopping/Shopify_Query.php

@@ -38,10 +38,10 @@
  * @phpstan-type ShopifyGraphQLPriceRange array{minVariantPrice: array{amount: int, currencyCode: string}}
  * @phpstan-type ShopifyGraphQLProductImage array{url: string, altText: string}
  * @phpstan-type ShopifyGraphQLProduct array{id: string, handle: string, title: string, vendor: string, description: string, onlineStoreUrl?: string, images: array{edges: array{node: ShopifyGraphQLProductImage}[]}, priceRange: ShopifyGraphQLPriceRange}
- * @phpstan-type ShopifyGraphQLResponse array{errors?: ShopifyGraphQLError, data: array{products: array{edges: array{node: ShopifyGraphQLProduct}[]}}}
+ * @phpstan-type ShopifyGraphQLResponse array{errors?: ShopifyGraphQLError, data: array{products: array{edges: array{node: ShopifyGraphQLProduct}[], pageInfo: array{hasNextPage: bool, endCursor: string}}}}
  */
 class Shopify_Query implements Product_Query {
-	protected const API_VERSION = '2022-01';
+	protected const API_VERSION = '2022-04';
 
 	/**
 	 * Settings instance.
@@ -150,18 +150,22 @@ protected function execute_query( string $query ) {
 	 *
 	 * @since 1.21.0
 	 *
-	 * @param string $search_term Search term to filter products by.
-	 * @param string $orderby Sort collection by product attribute.
-	 * @param string $order Order sort attribute ascending or descending.
-	 * @return string The assembled GraphQL query.
+	 * @param string $search_term  Search term to filter products by.
+	 * @param string $after        The cursor to retrieve nodes after in the connection.
+	 * @param int    $per_page     Number of products to be fetched.
+	 * @param string $orderby      Sort collection by product attribute.
+	 * @param string $order        Order sort attribute ascending or descending.
+	 * @return string              The assembled GraphQL query.
 	 */
-	protected function get_products_query( string $search_term, string $orderby, string $order ): string {
+	protected function get_products_query( string $search_term, string $after, int $per_page, string $orderby, string $order ): string {
 		$search_string = empty( $search_term ) ? '*' : '*' . $search_term . '*';
 		$sortkey       = 'date' === $orderby ? 'CREATED_AT' : strtoupper( $orderby );
 		$reverse       = 'asc' === $order ? 'false' : 'true';
+		$after         = empty( $after ) ? 'null' : sprintf( '"%s"', $after );
+
 		return <<<QUERY
 {
-  products(first: 100, sortKey: $sortkey, reverse: $reverse, query: "title:$search_string") {
+  products(first: $per_page, after: $after, sortKey: $sortkey, reverse: $reverse, query: "title:$search_string") {
     edges {
       node {
         id
@@ -186,6 +190,10 @@ protected function get_products_query( string $search_term, string $orderby, str
         }
       }
     }
+    pageInfo {
+       hasNextPage
+       endCursor
+    }
   }
 }
 QUERY;
@@ -198,34 +206,34 @@ protected function get_products_query( string $search_term, string $orderby, str
 	 *
 	 * @since 1.21.0
 	 *
-	 * @param string $search_term Search term to filter products by.
-	 * @param string $orderby Sort retrieved products by parameter.
-	 * @param string $order   Whether to order products in ascending or descending order.
-	 *                        Accepts 'asc' (ascending) or 'desc' (descending).
-	 * @return array|WP_Error Response data or error object on failure.
+	 * @param string $search_term  Search term to filter products by.
+	 * @param string $after        The cursor to retrieve nodes after in the connection.
+	 * @param int    $per_page     Number of products to be fetched.
+	 * @param string $orderby      Sort retrieved products by parameter.
+	 * @param string $order        Whether to order products in ascending or descending order.
+	 *                             Accepts 'asc' (ascending) or 'desc' (descending).
+	 * @return array|WP_Error      Response data or error object on failure.
 	 */
-	protected function fetch_remote_products( string $search_term, string $orderby, string $order ) {
-
+	protected function get_remote_products( string $search_term, string $after, int $per_page, string $orderby, string $order ) {
 		/**
 		 * Filters the Shopify products data TTL value.
 		 *
 		 * @since 1.21.0
 		 *
 		 * @param int $time Time to live (in seconds). Default is 5 minutes.
 		 */
-		$cache_ttl = apply_filters( 'web_stories_shopify_data_cache_ttl', 5 * MINUTE_IN_SECONDS );
-		$cache_key = 'web_stories_shopify_data_' . md5( $search_term . '-' . $orderby . '-' . $order );
+		$cache_ttl  = apply_filters( 'web_stories_shopify_data_cache_ttl', 5 * MINUTE_IN_SECONDS );
+		$cache_args = (string) wp_json_encode( compact( 'search_term', 'after', 'per_page', 'orderby', 'order' ) );
+		$cache_key  = 'web_stories_shopify_data_' . md5( $cache_args );
 
 		$data = get_transient( $cache_key );
 
 		if ( \is_string( $data ) && ! empty( $data ) ) {
 			return (array) json_decode( $data, true );
 		}
 
-		$query = $this->get_products_query( $search_term, $orderby, $order );
-
-		$body = $this->execute_query( $query );
-
+		$query = $this->get_products_query( $search_term, $after, $per_page, $orderby, $order );
+		$body  = $this->execute_query( $query );
 		if ( is_wp_error( $body ) ) {
 			return $body;
 		}
@@ -236,10 +244,8 @@ protected function fetch_remote_products( string $search_term, string $orderby,
 		 * @var ShopifyGraphQLResponse $result
 		 */
 		$result = json_decode( $body, true );
-
 		if ( isset( $result['errors'] ) ) {
 			$wp_error = new WP_Error();
-
 			foreach ( $result['errors'] as $error ) {
 				$error_code = $error['extensions']['code'];
 				// https://shopify.dev/api/storefront#status_and_error_codes.
@@ -260,7 +266,7 @@ protected function fetch_remote_products( string $search_term, string $orderby,
 						$wp_error->add( 'rest_unknown', __( 'Error fetching products from Shopify.', 'web-stories' ), [ 'status' => 500 ] );
 				}
 			}
-		
+
 			return $wp_error;
 		}
 
@@ -270,26 +276,64 @@ protected function fetch_remote_products( string $search_term, string $orderby,
 		return $result;
 	}
 
-
+	/**
+	 * Remotely fetches all products from the store.
+	 *
+	 * @since 1.21.0
+	 *
+	 * @param string $search_term Search term to filter products by.
+	 * @param int    $page        Number of page for paginated requests.
+	 * @param int    $per_page    Number of products to be fetched.
+	 * @param string $orderby     Sort retrieved products by parameter.
+	 * @param string $order       Whether to order products in ascending or descending order.
+	 *                            Accepts 'asc' (ascending) or 'desc' (descending).
+	 * @return array|WP_Error Response data or error object on failure.
+	 */
+	protected function fetch_remote_products( string $search_term, int $page, int $per_page, string $orderby, string $order ) {
+		$after = '';
+		if ( $page > 1 ) {
+			// Loop around all the pages, getting the endCursor of each page, until you get the last one.
+			for ( $i = 1; $i < $page; $i ++ ) {
+				$result = $this->get_remote_products( $search_term, $after, $per_page, $orderby, $order );
+				if ( is_wp_error( $result ) ) {
+					return $result;
+				}
+
+				$has_next_page = $result['data']['products']['pageInfo']['hasNextPage'];
+				if ( ! $has_next_page ) {
+					return new WP_Error( 'rest_no_page', __( 'Error fetching products from Shopify.', 'web-stories' ), [ 'status' => 404 ] );
+				}
+				$after = (string) $result['data']['products']['pageInfo']['endCursor'];
+			}
+		}
+
+		$result = $this->get_remote_products( $search_term, $after, $per_page, $orderby, $order );
+
+		return $result;
+	}
+
 	/**
 	 * Get products by search term.
 	 *
 	 * @since 1.21.0
 	 *
 	 * @param string $search_term Search term.
-	 * @param string $orderby Sort retrieved products by parameter. Default 'date'.
-	 * @param string $order   Whether to order products in ascending or descending order.
-	 *                        Accepts 'asc' (ascending) or 'desc' (descending). Default 'desc'.
-	 * @return Product[]|WP_Error
+	 * @param int    $page        Number of page for paginated requests.
+	 * @param int    $per_page    Number of products to be fetched.
+	 * @param string $orderby     Sort retrieved products by parameter. Default 'date'.
+	 * @param string $order       Whether to order products in ascending or descending order.
+	 *                            Accepts 'asc' (ascending) or 'desc' (descending). Default 'desc'.
+	 * @return array|WP_Error
 	 */
-	public function get_search( string $search_term, string $orderby = 'date', string $order = 'desc' ) {
-		$result = $this->fetch_remote_products( $search_term, $orderby, $order );
-
+	public function get_search( string $search_term, int $page = 1, int $per_page = 100, string $orderby = 'date', string $order = 'desc' ) {
+		$result = $this->fetch_remote_products( $search_term, $page, $per_page, $orderby, $order );
 		if ( is_wp_error( $result ) ) {
 			return $result;
 		}
 
-		$results = [];
+		$products = [];
+
+		$has_next_page = $result['data']['products']['pageInfo']['hasNextPage'] ?? false;
 
 		foreach ( $result['data']['products']['edges'] as $edge ) {
 			$product = $edge['node'];
@@ -309,7 +353,7 @@ public function get_search( string $search_term, string $orderby = 'date', strin
 			// In this case, we can fall back to a manually constructed product URL.
 			$product_url = $product['onlineStoreUrl'] ?? sprintf( 'https://%1$s/products/%2$s/', $this->get_host(), $product['handle'] );
 
-			$results[] = new Product(
+			$products[] = new Product(
 				[
 					'id'             => $product['id'],
 					'title'          => $product['title'],
@@ -327,6 +371,6 @@ public function get_search( string $search_term, string $orderby = 'date', strin
 			);
 		}
 
-		return $results;
+		return compact( 'products', 'has_next_page' );
 	}
 }