[volume-9] Product Ranking with Redis

apps/commerce-api/src/main/java/com/loopers/application/product/ProductDetailInfo.java

@@ -1,39 +1,25 @@
 package com.loopers.application.product;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder;
 import com.loopers.domain.common.vo.Money;
 import com.loopers.domain.product.vo.Stock;
 import lombok.Builder;
+import lombok.Getter;
 
+@Getter
 @Builder
-@JsonDeserialize(builder = ProductDetailInfo.ProductDetailInfoBuilder.class)
 public class ProductDetailInfo {
 
     private final Long id;
     private final String name;
     private final String description;
+    private final Long brandId;
     private final String brandName;
     private final String brandDescription;
     private final Money price;
     private final Stock stock;
     private final int likeCount;
-    private final boolean isLikedByMember;
-
-    public Long getId() { return id; }
-    public String getName() { return name; }
-    public String getDescription() { return description; }
-    public String getBrandName() { return brandName; }
-    public String getBrandDescription() { return brandDescription; }
-    public Money getPrice() { return price; }
-    public Stock getStock() { return stock; }
-    public int getLikeCount() { return likeCount; }
-
     @JsonProperty("likedByMember")
-    public boolean isLikedByMember() { return isLikedByMember; }
-
-    @JsonPOJOBuilder(withPrefix = "")
-    public static class ProductDetailInfoBuilder {
-    }
+    private final boolean isLikedByMember;
+    private final Integer ranking;  // 순위 (1-based), 순위권 밖이면 null
 }

apps/commerce-api/src/main/java/com/loopers/application/product/ProductFacade.java

@@ -2,13 +2,12 @@
 
 import com.loopers.application.event.product.ProductViewedEvent;
 import com.loopers.domain.like.service.LikeReadService;
-import com.loopers.domain.product.Product;
-import com.loopers.domain.product.repository.ProductRepository;
 import com.loopers.domain.product.service.ProductReadService;
 import com.loopers.domain.product.command.ProductSearchFilter;
 import com.loopers.domain.product.enums.ProductSortCondition;
 import com.loopers.infrastructure.cache.ProductDetailCache;
 import com.loopers.infrastructure.cache.ProductListCache;
+import com.loopers.infrastructure.cache.ProductRankingCache;
 import lombok.RequiredArgsConstructor;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.data.domain.Page;
@@ -29,7 +28,7 @@ public class ProductFacade {
     private final LikeReadService likeReadService;
     private final ProductDetailCache productDetailCache;
     private final ProductListCache productListCache;
-    private final ProductRepository productRepository;
+    private final ProductRankingCache productRankingCache;
     private final ApplicationEventPublisher eventPublisher;
 
     @Transactional(readOnly = true)
@@ -100,33 +99,33 @@ public ProductDetailInfo getProductDetail(Long productId, Long memberIdOrNull) {
                     return result;
                 });
 
-        // 2. Product 엔티티 조회 (brandId 획득용)
-        Product product = productRepository.findById(productId)
-                .orElseThrow(() -> new com.loopers.support.error.CoreException(
-                        com.loopers.support.error.ErrorType.NOT_FOUND,
-                        "상품을 찾을 수 없습니다."));
-
-        // 3. isLikedByMember 동적 계산
+        // 2. isLikedByMember 동적 계산
         boolean isLiked = memberIdOrNull != null && likeReadService.isLikedBy(memberIdOrNull, productId);
 
-        // 4. isLikedByMember 필드만 교체해서 반환
+        // 3. 순위 조회 (실시간)
+        Integer ranking = productRankingCache.getRank(productId);
+
+        // 4. 동적 필드(isLikedByMember, ranking)를 교체해서 반환
         ProductDetailInfo result = ProductDetailInfo.builder()
                 .id(cachedInfo.getId())
                 .name(cachedInfo.getName())
                 .description(cachedInfo.getDescription())
+                .brandId(cachedInfo.getBrandId())
                 .brandName(cachedInfo.getBrandName())
                 .brandDescription(cachedInfo.getBrandDescription())
                 .price(cachedInfo.getPrice())
                 .stock(cachedInfo.getStock())
                 .likeCount(cachedInfo.getLikeCount())
-                .isLikedByMember(isLiked)  // ⭐ 동적 계산
+                .isLikedByMember(isLiked)
+                .ranking(ranking)
                 .build();
 
         // 5. ProductViewedEvent 발행 (조회수 집계)
+        // brandId는 캐시된 정보에서 가져옴 (불필요한 DB 조회 제거)
         eventPublisher.publishEvent(new ProductViewedEvent(
             memberIdOrNull,  // 비로그인 사용자는 null
             productId,
-            product.getBrandId(),
+            cachedInfo.getBrandId(),
             LocalDateTime.now()
         ));
 

apps/commerce-api/src/main/java/com/loopers/application/product/ProductSummaryInfo.java

@@ -1,32 +1,19 @@
 package com.loopers.application.product;
 
 import com.fasterxml.jackson.annotation.JsonProperty;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonPOJOBuilder;
 import com.loopers.domain.common.vo.Money;
 import lombok.Builder;
+import lombok.Getter;
 
+@Getter
 @Builder
-@JsonDeserialize(builder = ProductSummaryInfo.ProductSummaryInfoBuilder.class)
 public class ProductSummaryInfo {
 
     private final Long id;
     private final String name;
     private final String brandName;
     private final Money price;
     private final int likeCount;
-    private final boolean isLikedByMember;
-
-    public Long getId() { return id; }
-    public String getName() { return name; }
-    public String getBrandName() { return brandName; }
-    public Money getPrice() { return price; }
-    public int getLikeCount() { return likeCount; }
-
     @JsonProperty("likedByMember")
-    public boolean isLikedByMember() { return isLikedByMember; }
-
-    @JsonPOJOBuilder(withPrefix = "")
-    public static class ProductSummaryInfoBuilder {
-    }
+    private final boolean isLikedByMember;
 }

apps/commerce-api/src/main/java/com/loopers/application/ranking/RankingFacade.java

@@ -0,0 +1,111 @@
+package com.loopers.application.ranking;
+
+import com.loopers.application.ranking.RankingInfo.RankingItemInfo;
+import com.loopers.application.ranking.RankingInfo.RankingPageInfo;
+import com.loopers.domain.brand.Brand;
+import com.loopers.domain.brand.repository.BrandRepository;
+import com.loopers.domain.product.Product;
+import com.loopers.domain.product.repository.ProductRepository;
+import com.loopers.infrastructure.cache.ProductRankingCache;
+import com.loopers.infrastructure.cache.ProductRankingCache.RankingEntry;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.time.LocalDate;
+import java.time.format.DateTimeFormatter;
+import java.time.format.DateTimeParseException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+@Slf4j
+@RequiredArgsConstructor
+@Component
+@Transactional(readOnly = true)
+public class RankingFacade {
+
+    private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("yyyyMMdd");
+
+    private final ProductRankingCache productRankingCache;
+    private final ProductRepository productRepository;
+    private final BrandRepository brandRepository;
+
+    /** @param page 0-based */
+    public RankingPageInfo getRankings(String date, int page, int size) {
+        // 날짜 검증 및 기본값 처리
+        String targetDate = validateAndNormalizeDate(date);
+
+        // 1. ZSET에서 랭킹 조회
+        List<RankingEntry> rankingEntries = productRankingCache.getTopRankings(targetDate, page, size);
+
+        if (rankingEntries.isEmpty()) {
+            return RankingPageInfo.of(Collections.emptyList(), targetDate, page, size, 0);
+        }
+
+        // 2. 상품 ID 목록 추출
+        List<Long> productIds = rankingEntries.stream()
+                .map(RankingEntry::productId)
+                .toList();
+
+        // 3. 상품 정보 조회
+        List<Product> products = productRepository.findByIdIn(productIds);
+        Map<Long, Product> productMap = products.stream()
+                .collect(Collectors.toMap(Product::getId, Function.identity()));
+
+        // 4. 브랜드 정보 조회 (N+1 방지)
+        List<Long> brandIds = products.stream()
+                .map(Product::getBrandId)
+                .distinct()
+                .toList();
+        List<Brand> brands = brandRepository.findByIdIn(brandIds);
+        Map<Long, Brand> brandMap = brands.stream()
+                .collect(Collectors.toMap(Brand::getId, Function.identity()));
+
+        // 5. 응답 생성
+        List<RankingItemInfo> rankings = rankingEntries.stream()
+                .map(entry -> {
+                    Product product = productMap.get(entry.productId());
+                    if (product == null) {
+                        log.warn("[Ranking] Product not found - productId: {}", entry.productId());
+                        return null;
+                    }
+                    Brand brand = brandMap.get(product.getBrandId());
+                    String brandName = brand != null ? brand.getName() : "Unknown";
+
+                    return new RankingItemInfo(
+                            entry.rank(),
+                            product.getId(),
+                            product.getName(),
+                            brandName,
+                            product.getPrice(),
+                            product.getLikeCount(),
+                            entry.score()
+                    );
+                })
+                .filter(item -> item != null)
+                .toList();
+
+        // 6. 전체 개수 조회
+        long totalCount = productRankingCache.getTotalCount(targetDate);
+
+        return RankingPageInfo.of(rankings, targetDate, page, size, totalCount);
+    }
+
+    /** @throws IllegalArgumentException 유효하지 않은 날짜 형식 */
+    private String validateAndNormalizeDate(String date) {
+        if (date == null || date.isBlank()) {
+            return productRankingCache.getTodayDate();
+        }
+
+        try {
+            LocalDate.parse(date, DATE_FORMATTER);
+            return date;
+        } catch (DateTimeParseException e) {
+            throw new IllegalArgumentException("Invalid date format. Expected yyyyMMdd, got: " + date);
+        }
+    }
+}

apps/commerce-api/src/main/java/com/loopers/application/ranking/RankingInfo.java

@@ -0,0 +1,40 @@
+package com.loopers.application.ranking;
+
+import com.loopers.domain.common.vo.Money;
+
+import java.util.List;
+
+public class RankingInfo {
+
+    public record RankingPageInfo(
+            List<RankingItemInfo> rankings,
+            String date,
+            int page,
+            int size,
+            long totalCount,
+            int totalPages,
+            boolean hasNext
+    ) {
+        public static RankingPageInfo of(
+                List<RankingItemInfo> rankings,
+                String date,
+                int page,
+                int size,
+                long totalCount
+        ) {
+            int totalPages = size > 0 ? (int) Math.ceil((double) totalCount / size) : 0;
+            boolean hasNext = page < totalPages - 1;
+            return new RankingPageInfo(rankings, date, page, size, totalCount, totalPages, hasNext);
+        }
+    }
+
+    public record RankingItemInfo(
+            int rank,
+            Long productId,
+            String productName,
+            String brandName,
+            Money price,
+            int likeCount,
+            Double score
+    ) {}
+}

apps/commerce-api/src/main/java/com/loopers/domain/product/service/ProductReadService.java

@@ -51,12 +51,14 @@ public ProductDetailInfo getProductDetail(Long productId, Long memberIdOrNull) {
                 .id(product.getId())
                 .name(product.getName())
                 .description(product.getDescription())
+                .brandId(product.getBrandId())
                 .brandName(brand.getName())
                 .brandDescription(brand.getDescription())
                 .price(product.getPrice())
                 .stock(product.getStock())
                 .likeCount(product.getLikeCount())
                 .isLikedByMember(isLikedByMember)
+                .ranking(null)  // 캐시 저장용, Facade에서 실시간 조회로 교체
                 .build();
     }
 

apps/commerce-api/src/main/java/com/loopers/infrastructure/cache/CacheKeyGenerator.java

@@ -50,4 +50,10 @@ public static String productLikeCountKey(Long productId) {
     public static String productLikeCountKeyPattern() {
         return String.format("product:like:count:%s:*", VERSION);
     }
+
+    // Daily ranking ZSET key
+    public static String dailyRankingKey(String date) {
+        return String.format("ranking:all:%s:%s", VERSION, date);
+        // 예: "ranking:all:v1:20251223"
+    }
 }