feat: 랭킹 API date 파라미터 유효성 검증 추가

Author: sylee6529

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

@@ -13,6 +13,9 @@
 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;
@@ -25,6 +28,8 @@
 @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;
@@ -37,8 +42,8 @@ public class RankingFacade {
      * @return 랭킹 페이지 정보
      */
     public RankingPageInfo getRankings(String date, int page, int size) {
-        // 날짜 기본값: 오늘
-        String targetDate = date != null ? date : productRankingCache.getTodayDate();
+        // 날짜 검증 및 기본값 처리
+        String targetDate = validateAndNormalizeDate(date);
 
         // 1. ZSET에서 랭킹 조회
         List<RankingEntry> rankingEntries = productRankingCache.getTopRankings(targetDate, page, size);
@@ -95,4 +100,23 @@ public RankingPageInfo getRankings(String date, int page, int size) {
 
         return RankingPageInfo.of(rankings, targetDate, page, size, totalCount);
     }
+
+    /**
+     * 날짜 파라미터 검증 및 정규화
+     * @param date 날짜 문자열 (yyyyMMdd 형식) 또는 null
+     * @return 검증된 날짜 문자열 (null이면 오늘 날짜)
+     * @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/test/java/com/loopers/application/ranking/RankingFacadeTest.java

@@ -20,6 +20,7 @@
 import java.util.List;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.mockito.ArgumentMatchers.*;
 import static org.mockito.Mockito.*;
 
@@ -174,4 +175,28 @@ private Brand createBrand(Long id, String name) {
         when(brand.getName()).thenReturn(name);
         return brand;
     }
+
+    @Test
+    @DisplayName("getRankings - 잘못된 날짜 형식은 예외 발생")
+    void getRankings_throwsExceptionForInvalidDateFormat() {
+        // given
+        String invalidDate = "2025-12-26";  // yyyy-MM-dd 형식 (잘못됨)
+
+        // when & then
+        assertThatThrownBy(() -> rankingFacade.getRankings(invalidDate, 0, 10))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("Invalid date format");
+    }
+
+    @Test
+    @DisplayName("getRankings - 존재하지 않는 날짜는 예외 발생")
+    void getRankings_throwsExceptionForNonExistentDate() {
+        // given
+        String invalidDate = "20251332";  // 13월 32일 (존재하지 않는 날짜)
+
+        // when & then
+        assertThatThrownBy(() -> rankingFacade.getRankings(invalidDate, 0, 10))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("Invalid date format");
+    }
 }