[FEAT] add follow and unfollow API

src/main/kotlin/healthiee/rest/api/member/MemberApiController.kt

@@ -2,20 +2,29 @@ package healthiee.rest.api.member
 
 import healthiee.rest.api.member.dto.MemberDto
 import healthiee.rest.api.member.dto.response.CheckMemberResponse
+import healthiee.rest.domain.member.Member
+import healthiee.rest.lib.error.ApiException
+import healthiee.rest.lib.error.ApplicationErrorCode.NOT_FOUND_MEMBER
 import healthiee.rest.lib.response.BaseResponse
 import healthiee.rest.repository.member.MemberRepository
+import healthiee.rest.service.FollowService
 import healthiee.rest.service.MemberService
+import org.springframework.data.repository.findByIdOrNull
 import org.springframework.http.HttpStatus
 import org.springframework.http.ResponseEntity
 import org.springframework.security.access.prepost.PreAuthorize
+import org.springframework.security.core.annotation.AuthenticationPrincipal
+import org.springframework.web.bind.annotation.DeleteMapping
 import org.springframework.web.bind.annotation.GetMapping
 import org.springframework.web.bind.annotation.PathVariable
+import org.springframework.web.bind.annotation.PostMapping
 import org.springframework.web.bind.annotation.RestController
 import java.util.*
 
 @RestController
 class MemberApiController(
     private val memberService: MemberService,
+    private val followService: FollowService,
     private val memberRepository: MemberRepository,
 ) {
 
@@ -34,4 +43,42 @@ class MemberApiController(
         return ResponseEntity.ok(BaseResponse(code = HttpStatus.OK.value(), data = CheckMemberResponse(exist)))
     }
 
+    @PostMapping("/v1/members/{memberId}/follow")
+    @PreAuthorize("hasRole('MEMBER')")
+    fun followMember(
+        @AuthenticationPrincipal member: Member,
+        @PathVariable("memberId") targetMemberId: UUID,
+    ): ResponseEntity<BaseResponse<Any>> {
+        val findMember = memberRepository.findByIdOrNull(targetMemberId)
+            ?: throw ApiException(NOT_FOUND_MEMBER)
+
+        followService.follow(member, findMember)
+
+        return ResponseEntity.ok(
+            BaseResponse(
+                code = HttpStatus.OK.value(),
+                message = "팔로우가 완료 되었습니다",
+            )
+        )
+    }
+
+    @DeleteMapping("/v1/members/{memberId}/follow")
+    @PreAuthorize("hasRole('MEMBER')")
+    fun unfollowMember(
+        @AuthenticationPrincipal member: Member,
+        @PathVariable("memberId") targetMemberId: UUID,
+    ): ResponseEntity<BaseResponse<Any>> {
+        val findMember = memberRepository.findByIdOrNull(targetMemberId)
+            ?: throw ApiException(NOT_FOUND_MEMBER)
+
+        followService.unfollow(member, findMember)
+
+        return ResponseEntity.ok(
+            BaseResponse(
+                code = HttpStatus.OK.value(),
+                message = "팔로우가 취소 되었습니다",
+            )
+        )
+    }
+
 }

src/main/kotlin/healthiee/rest/domain/base/BaseEntity.kt

@@ -22,6 +22,11 @@ abstract class BaseEntity {
         protected set
 
     @Column(nullable = false)
-    val deleted: Boolean = false
+    var deleted: Boolean = false
+        private set
+
+    fun delete() {
+        deleted = true
+    }
 
 }

src/main/kotlin/healthiee/rest/domain/follow/Follow.kt

@@ -30,4 +30,8 @@ class Follow(
     @Column(name = "follow_id")
     val id: Long = 0L
 
+    companion object {
+        fun createFollow(member: Member, targetMember: Member) = Follow(member, targetMember)
+    }
+
 }

src/main/kotlin/healthiee/rest/lib/error/ApplicationErrorCode.kt

@@ -5,12 +5,17 @@ import org.springframework.http.HttpStatus
 enum class ApplicationErrorCode(
     private val _httpStatus: HttpStatus,
     private val _message: String,
-): ErrorCode {
+) : ErrorCode {
     // Not Found
     NOT_FOUND_MEMBER(HttpStatus.NOT_FOUND, "멤버를 찾을 수 없습니다"),
     NOT_FOUND_CODE(HttpStatus.NOT_FOUND, "코드를 찾을 수 없습니다"),
+    NOT_FOUND_FOLLOW(HttpStatus.NOT_FOUND, "팔로우를 찾을 수 없습니다"),
+
     // Forbidden
-    FORBIDDEN_INVALID_REFRESH_TOKEN(HttpStatus.FORBIDDEN, "유효하지 않는 리프레쉬 토큰입니다")
+    FORBIDDEN_INVALID_REFRESH_TOKEN(HttpStatus.FORBIDDEN, "유효하지 않는 리프레쉬 토큰입니다"),
+
+    // Bad Request
+    BAD_REQUEST_ALREADY_EXIST_FOLLOW(HttpStatus.BAD_REQUEST, "이미 팔로우가 되어 있습니다"),
     ;
 
     override val httpStatus: HttpStatus

src/main/kotlin/healthiee/rest/repository/follow/FollowCustomRepository.kt

@@ -0,0 +1,10 @@
+package healthiee.rest.repository.follow
+
+import healthiee.rest.domain.follow.Follow
+import healthiee.rest.domain.member.Member
+
+interface FollowCustomRepository {
+
+    fun findByMember(member: Member, targetMember: Member): Follow?
+
+}

src/main/kotlin/healthiee/rest/repository/follow/FollowCustomRepositoryImpl.kt

@@ -0,0 +1,23 @@
+package healthiee.rest.repository.follow
+
+import com.querydsl.jpa.impl.JPAQueryFactory
+import healthiee.rest.domain.follow.Follow
+import healthiee.rest.domain.follow.QFollow.follow
+import healthiee.rest.domain.member.Member
+import java.util.*
+
+class FollowCustomRepositoryImpl(
+    private val queryFactory: JPAQueryFactory,
+) : FollowCustomRepository {
+
+    override fun findByMember(member: Member, targetMember: Member): Follow? {
+        return queryFactory.selectFrom(follow)
+            .where(
+                follow.member.eq(member),
+                follow.targetMember.eq(targetMember),
+                follow.deleted.eq(false)
+            )
+            .fetchOne()
+
+    }
+}

src/main/kotlin/healthiee/rest/repository/follow/FollowRepository.kt

@@ -6,7 +6,7 @@ import org.springframework.data.jpa.repository.JpaRepository
 import org.springframework.stereotype.Repository
 
 @Repository
-interface FollowRepository : JpaRepository<Follow, Long> {
+interface FollowRepository : JpaRepository<Follow, Long>, FollowCustomRepository {
     fun countByMember(member: Member): Int // 팔로우 수
     fun countByTargetMember(member: Member): Int // 팔로워 수
 }

src/main/kotlin/healthiee/rest/service/FollowService.kt

@@ -0,0 +1,38 @@
+package healthiee.rest.service
+
+import healthiee.rest.domain.follow.Follow
+import healthiee.rest.domain.member.Member
+import healthiee.rest.lib.error.ApiException
+import healthiee.rest.lib.error.ApplicationErrorCode.BAD_REQUEST_ALREADY_EXIST_FOLLOW
+import healthiee.rest.lib.error.ApplicationErrorCode.NOT_FOUND_FOLLOW
+import healthiee.rest.repository.follow.FollowRepository
+import org.springframework.stereotype.Service
+import org.springframework.transaction.annotation.Transactional
+
+@Service
+@Transactional(readOnly = true)
+class FollowService(
+    val followRepository: FollowRepository,
+) {
+
+    @Transactional
+    fun follow(member: Member, targetMember: Member) {
+        val findFollow = followRepository.findByMember(member, targetMember)
+        findFollow?.let { throw ApiException(BAD_REQUEST_ALREADY_EXIST_FOLLOW) }
+
+        followRepository.save(Follow.createFollow(member, targetMember))
+    }
+
+    @Transactional
+    fun unfollow(member: Member, targetMember: Member) {
+        val findFollow = followRepository.findByMember(member, targetMember)
+            ?: throw ApiException(NOT_FOUND_FOLLOW)
+
+        findFollow.delete()
+    }
+
+    fun getFollowingCount(member: Member): Int = followRepository.countByMember(member)
+
+    fun getFollowerCount(member: Member): Int = followRepository.countByTargetMember(member)
+
+}

src/main/kotlin/healthiee/rest/service/MemberService.kt

@@ -3,7 +3,6 @@ package healthiee.rest.service
 import healthiee.rest.api.member.dto.MemberDto
 import healthiee.rest.lib.error.ApiException
 import healthiee.rest.lib.error.ApplicationErrorCode.NOT_FOUND_MEMBER
-import healthiee.rest.repository.follow.FollowRepository
 import healthiee.rest.repository.member.MemberRepository
 import org.springframework.data.repository.findByIdOrNull
 import org.springframework.stereotype.Service
@@ -14,17 +13,20 @@ import java.util.*
 @Transactional(readOnly = true)
 class MemberService(
     val memberRepository: MemberRepository,
-    val followRepository: FollowRepository,
+    val followService: FollowService,
 ) {
 
     fun getMember(id: UUID): MemberDto {
         val findMember =
             memberRepository.findByIdOrNull(id) ?: throw ApiException(NOT_FOUND_MEMBER)
 
-        val followingCount = followRepository.countByMember(findMember)
-        val followerCount = followRepository.countByTargetMember(findMember)
-
-        return MemberDto.create(MemberDto.Params(findMember, followingCount, followerCount))
+        return MemberDto.create(
+            MemberDto.Params(
+                findMember,
+                followService.getFollowingCount(findMember),
+                followService.getFollowerCount(findMember),
+            )
+        )
     }
 
 }