feat: 팔로워 조회 API 구현 (#86)

* feat: 팔로워 목록 조회 API 구현 (#65) * fix: size default값 변경 (#65) * feat: 응답에 cursorId 포함 (#65)
8-Sprinters · Feb 8, 2024 · c123e8c · c123e8c
1 parent 44d0072
commit c123e8c
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Showing 6 changed files with 128 additions and 2 deletions.
diff --git a/src/main/java/com/listywave/user/application/dto/FollowersResponse.java b/src/main/java/com/listywave/user/application/dto/FollowersResponse.java
@@ -0,0 +1,54 @@
+package com.listywave.user.application.dto;
+
+import com.listywave.user.application.domain.User;
+import java.util.Collections;
+import java.util.List;
+import lombok.Builder;
+
+@Builder
+public record FollowersResponse(
+        List<FollowerInfo> followers,
+        int totalCount,
+        Long cursorId,
+        boolean hasNext
+) {
+
+    public static FollowersResponse of(List<User> users, int totalCount, boolean hasNext) {
+        return FollowersResponse.builder()
+                .followers(FollowerInfo.toList(users))
+                .totalCount(totalCount)
+                .cursorId(users.get(users.size() - 1).getId())
+                .hasNext(hasNext)
+                .build();
+    }
+
+    public static FollowersResponse empty() {
+        return FollowersResponse.builder()
+                .followers(Collections.emptyList())
+                .totalCount(0)
+                .hasNext(false)
+                .build();
+    }
+}
+
+@Builder
+record FollowerInfo(
+        Long id,
+        String nickname,
+        String profileImageUrl
+) {
+
+    public static List<FollowerInfo> toList(List<User> users) {
+        return users.stream()
+                .map(FollowerInfo::of)
+                .toList();
+    }
+
+    public static FollowerInfo of(User user) {
+        return FollowerInfo.builder()
+                .id(user.getId())
+                .nickname(user.getNickname())
+                .profileImageUrl(user.getProfileImageUrl())
+                .build();
+    }
+}
diff --git a/src/main/java/com/listywave/user/application/service/UserService.java b/src/main/java/com/listywave/user/application/service/UserService.java
@@ -8,6 +8,7 @@
 import com.listywave.user.application.domain.User;
 import com.listywave.user.application.dto.AllUserListsResponse;
 import com.listywave.user.application.dto.AllUserResponse;
+import com.listywave.user.application.dto.FollowersResponse;
 import com.listywave.user.application.dto.FollowingsResponse;
 import com.listywave.user.application.dto.RecommendUsersResponse;
 import com.listywave.user.application.dto.UserInfoResponse;
@@ -103,7 +104,26 @@ public void unfollow(Long followingUserId, String accessToken) {
 
         followRepository.deleteByFollowingUserAndFollowerUser(followingUser, followerUser);
     }
-
+
+    public FollowersResponse getFollowers(Long userId, int size, int cursorId) {
+        User followingUser = userRepository.getById(userId);
+
+        List<Follow> follows = followRepository.findAllByFollowingUser(followingUser, size, cursorId);
+        List<User> followerUsers = follows.stream()
+                .map(Follow::getFollowerUser)
+                .toList();
+
+        if (followerUsers.isEmpty()) {
+            return FollowersResponse.empty();
+        }
+
+        int totalCount = followRepository.countByFollowingUser(followingUser);
+        if (followerUsers.size() > size) {
+            return FollowersResponse.of(followerUsers.subList(0, size), totalCount, true);
+        }
+        return FollowersResponse.of(followerUsers, totalCount, false);
+    }
+
      @Transactional(readOnly = true)
      public List<RecommendUsersResponse> getRecommendUsers() {
          List<User> recommendUsers = userRepository.getRecommendUsers();

diff --git a/src/main/java/com/listywave/user/presentation/UserController.java b/src/main/java/com/listywave/user/presentation/UserController.java
@@ -5,6 +5,7 @@
 import com.listywave.list.application.domain.CategoryType;
 import com.listywave.user.application.dto.AllUserListsResponse;
 import com.listywave.user.application.dto.AllUserResponse;
+import com.listywave.user.application.dto.FollowersResponse;
 import com.listywave.user.application.dto.FollowingsResponse;
 import com.listywave.user.application.dto.RecommendUsersResponse;
 import com.listywave.user.application.dto.UserInfoResponse;
@@ -59,6 +60,16 @@ ResponseEntity<FollowingsResponse> getFollowings(@PathVariable(name = "userId")
         return ResponseEntity.ok(response);
     }
 
+    @GetMapping("/users/{userId}/followers")
+    ResponseEntity<FollowersResponse> getFollowers(
+            @PathVariable(name = "userId") Long userId,
+            @RequestParam(name = "size", defaultValue = "20") int size,
+            @RequestParam(name = "cursorId", defaultValue = "0") int cursorId
+    ) {
+        FollowersResponse response = userService.getFollowers(userId, size, cursorId);
+        return ResponseEntity.ok(response);
+    }
+
     @PostMapping("/follow/{userId}")
     ResponseEntity<Void> follow(
             @PathVariable(value = "userId") Long followingUserId,

diff --git a/src/main/java/com/listywave/user/repository/follow/FollowRepository.java b/src/main/java/com/listywave/user/repository/follow/FollowRepository.java
@@ -2,12 +2,15 @@
 
 import com.listywave.user.application.domain.Follow;
 import com.listywave.user.application.domain.User;
+import com.listywave.user.repository.follow.custom.CustomFollowRepository;
 import java.util.List;
 import org.springframework.data.jpa.repository.JpaRepository;
 
-public interface FollowRepository extends JpaRepository<Follow, Long> {
+public interface FollowRepository extends JpaRepository<Follow, Long>, CustomFollowRepository {
 
     List<Follow> getAllByFollowerUser(User user);
 
     void deleteByFollowingUserAndFollowerUser(User following, User follower);
+
+    int countByFollowingUser(User user);
 }
diff --git a/src/main/java/com/listywave/user/repository/follow/custom/CustomFollowRepository.java b/src/main/java/com/listywave/user/repository/follow/custom/CustomFollowRepository.java
@@ -0,0 +1,10 @@
+package com.listywave.user.repository.follow.custom;
+
+import com.listywave.user.application.domain.Follow;
+import com.listywave.user.application.domain.User;
+import java.util.List;
+
+public interface CustomFollowRepository {
+
+    List<Follow> findAllByFollowingUser(User user, int size, int cursorId);
+}
diff --git a/...ain/java/com/listywave/user/repository/follow/custom/impl/CustomFollowRepositoryImpl.java b/...ain/java/com/listywave/user/repository/follow/custom/impl/CustomFollowRepositoryImpl.java
@@ -0,0 +1,28 @@
+package com.listywave.user.repository.follow.custom.impl;
+
+import static com.listywave.user.application.domain.QFollow.follow;
+
+import com.listywave.user.application.domain.Follow;
+import com.listywave.user.application.domain.User;
+import com.listywave.user.repository.follow.custom.CustomFollowRepository;
+import com.querydsl.jpa.impl.JPAQueryFactory;
+import java.util.List;
+import lombok.RequiredArgsConstructor;
+
+@RequiredArgsConstructor
+public class CustomFollowRepositoryImpl implements CustomFollowRepository {
+
+    private final JPAQueryFactory queryFactory;
+
+    @Override
+    public List<Follow> findAllByFollowingUser(User followingUser, int size, int cursorId) {
+        return queryFactory.selectFrom(follow)
+                .where(
+                        follow.followingUser.eq(followingUser),
+                        follow.followingUser.id.gt(cursorId)
+                )
+                .orderBy(follow.createdDate.desc())
+                .limit(size + 1)
+                .fetch();
+    }
+}