Feat: ttl 적용하여 캐싱 기능 개선 (#20)

* 조회수 증가 방식 수정

* 랭킹 조회 메서드 추가

* ConcertServiceImpl에 랭킹 조회 기능 추가

* ConcertController에 API 추가

Author: HeeMang-Lee

src/main/java/org/example/siljeun/domain/concert/controller/ConcertController.java

@@ -64,8 +64,13 @@ public ResponseEntity<ConcertDetailResponse> getConcertDetail(@PathVariable Long
     return ResponseEntity.ok(response);
   }
 
-  @GetMapping("/popular")
-  public ResponseEntity<List<ConcertSimpleResponse>> getPopularConcerts() {
-    return ResponseEntity.ok(concertService.getPopularConcerts());
+  @GetMapping("/popular/daily")
+  public ResponseEntity<List<ConcertSimpleResponse>> getDailyPopularConcerts() {
+    return ResponseEntity.ok(concertService.getDailyPopularConcerts());
+  }
+
+  @GetMapping("/popular/weekly")
+  public ResponseEntity<List<ConcertSimpleResponse>> getWeeklyPopularConcerts() {
+    return ResponseEntity.ok(concertService.getWeeklyPopularConcerts());
   }
 }

src/main/java/org/example/siljeun/domain/concert/service/ConcertCacheService.java

@@ -29,4 +29,10 @@ public List<Long> getTopConcertIds(int limit) {
         .toList();
   }
 
+  public List<Long> getTopConcertIds(String key, int limit) {
+    Set<Object> ids = redisTemplate.opsForZSet()
+        .reverseRange(key, 0, limit - 1);
+    return ids.stream().map(id -> Long.valueOf(id.toString())).toList();
+  }
+
 }

src/main/java/org/example/siljeun/domain/concert/service/ConcertService.java

@@ -18,5 +18,7 @@ public interface ConcertService {
 
   ConcertDetailResponse getConcertDetail(Long concertId);
 
-  List<ConcertSimpleResponse> getPopularConcerts();
+  List<ConcertSimpleResponse> getDailyPopularConcerts();
+
+  List<ConcertSimpleResponse> getWeeklyPopularConcerts();
 }

src/main/java/org/example/siljeun/domain/concert/service/ConcertServiceImpl.java

@@ -120,21 +120,26 @@ public ConcertDetailResponse getConcertDetail(Long concertId) {
   }
 
   @Override
-  public List<ConcertSimpleResponse> getPopularConcerts() {
-    List<Long> topIds = concertCacheService.getTopConcertIds(7);
-    List<Concert> concerts = concertRepository.findByIdIn(topIds);
+  public List<ConcertSimpleResponse> getDailyPopularConcerts() {
+    List<Long> ids = concertCacheService.getTopConcertIds("ranking:daily", 7);
+    return mapConcertsByIdOrder(ids);
+  }
 
+  @Override
+  public List<ConcertSimpleResponse> getWeeklyPopularConcerts() {
+    List<Long> ids = concertCacheService.getTopConcertIds("ranking:weekly", 7);
+    return mapConcertsByIdOrder(ids);
+  }
+
+  private List<ConcertSimpleResponse> mapConcertsByIdOrder(List<Long> ids) {
+    List<Concert> concerts = concertRepository.findByIdIn(ids);
     Map<Long, Concert> concertMap = concerts.stream()
         .collect(Collectors.toMap(Concert::getId, c -> c));
-
-    return topIds.stream()
+    return ids.stream()
         .map(concertMap::get)
         .filter(Objects::nonNull)
         .map(c -> new ConcertSimpleResponse(
-            c.getId(),
-            c.getTitle(),
-            c.getVenue().getName(),
-            c.getCategory().name()
+            c.getId(), c.getTitle(), c.getVenue().getName(), c.getCategory().name()
         ))
         .toList();
   }