feat : 팔로우 추가 / 취소 구현

src/main/java/com/codeit/todo/common/exception/follow/FollowNotFoundException.java

@@ -0,0 +1,14 @@
+package com.codeit.todo.common.exception.follow;
+
+import com.codeit.todo.common.exception.EntityNotFoundException;
+
+public class FollowNotFoundException extends EntityNotFoundException {
+    private static final String ENTITY_TYPE = "follow";
+
+    /**
+     * @param request    엔티티를 찾기 위해 요청한 값
+     */
+    public FollowNotFoundException(String request) {
+        super(request, ENTITY_TYPE);
+    }
+}

src/main/java/com/codeit/todo/domain/Follow.java

@@ -29,5 +29,10 @@ public Follow(User follower, User followee){
         this.followee = followee;
     }
 
-
+    public static Follow from(User follower, User followee) {
+        return Follow.builder()
+                .follower(follower)
+                .followee(followee)
+                .build();
+    }
 }

src/main/java/com/codeit/todo/repository/FollowRepository.java

@@ -7,6 +7,7 @@
 import org.springframework.data.repository.query.Param;
 
 import java.util.List;
+import java.util.Optional;
 
 public interface FollowRepository extends JpaRepository<Follow, Integer> {
     @Query(
@@ -28,5 +29,7 @@ public interface FollowRepository extends JpaRepository<Follow, Integer> {
 
     @Query("select f.followee.userId from Follow f where f.follower.userId = :userId")
     List<Integer> findFolloweeIdsByFollowerId(@Param("userId") int userId);
+
+    Optional<Follow> findByFollower_UserIdAndFollowee_UserId(int followerId, int followeeId);
 }
 

src/main/java/com/codeit/todo/service/follow/FollowService.java

@@ -1,9 +1,15 @@
 package com.codeit.todo.service.follow;
 
 import com.codeit.todo.web.dto.request.follow.ReadFollowRequest;
+import com.codeit.todo.web.dto.response.follow.CreateFollowResponse;
+import com.codeit.todo.web.dto.response.follow.DeleteFollowResponse;
 import com.codeit.todo.web.dto.response.follow.ReadFollowResponse;
 import org.springframework.data.domain.Slice;
 
 public interface FollowService {
     Slice<ReadFollowResponse> readFollows(int userId, ReadFollowRequest request);
+
+    CreateFollowResponse registerFollow(int followerId, int followeeId);
+
+    DeleteFollowResponse cancelFollow(int followerId, int followeeId);
 }

src/main/java/com/codeit/todo/service/follow/impl/FollowServiceImpl.java

@@ -1,11 +1,19 @@
 package com.codeit.todo.service.follow.impl;
 
+import com.codeit.todo.common.exception.auth.AuthorizationDeniedException;
+import com.codeit.todo.common.exception.follow.FollowNotFoundException;
+import com.codeit.todo.common.exception.user.UserNotFoundException;
 import com.codeit.todo.domain.Complete;
+import com.codeit.todo.domain.Follow;
+import com.codeit.todo.domain.User;
 import com.codeit.todo.repository.CompleteRepository;
 import com.codeit.todo.repository.FollowRepository;
 import com.codeit.todo.repository.LikesRepository;
+import com.codeit.todo.repository.UserRepository;
 import com.codeit.todo.service.follow.FollowService;
 import com.codeit.todo.web.dto.request.follow.ReadFollowRequest;
+import com.codeit.todo.web.dto.response.follow.CreateFollowResponse;
+import com.codeit.todo.web.dto.response.follow.DeleteFollowResponse;
 import com.codeit.todo.web.dto.response.follow.ReadFollowResponse;
 import com.codeit.todo.web.dto.response.slice.CustomSlice;
 import lombok.RequiredArgsConstructor;
@@ -26,6 +34,7 @@ public class FollowServiceImpl implements FollowService {
     private final FollowRepository followRepository;
     private final CompleteRepository completeRepository;
     private final LikesRepository likesRepository;
+    private final UserRepository userRepository;
 
     @Transactional(readOnly = true)
     @Override
@@ -55,4 +64,38 @@ public Slice<ReadFollowResponse> readFollows(int userId, ReadFollowRequest reque
 
         return new CustomSlice<>(responses, pageable, completes.hasNext(), nextCursor);
     }
+
+    @Override
+    public CreateFollowResponse registerFollow(int followerId, int followeeId) {
+        if (followRepository.existsByFollower_FollowerIdAndFollowee_FolloweeId(followeeId, followerId)) {
+            throw new AuthorizationDeniedException("이미 팔로우로 등록한 회원입니다.");
+        }
+
+        User follower = getUser(followerId);
+        User followee = getUser(followeeId);
+
+        Follow follow = Follow.from(follower, followee);
+        Follow savedFollow = followRepository.save(follow);
+
+        return CreateFollowResponse.fromEntity(savedFollow);
+    }
+
+    @Override
+    public DeleteFollowResponse cancelFollow(int followerId, int followeeId) {
+        if (!followRepository.existsByFollower_FollowerIdAndFollowee_FolloweeId(followeeId, followerId)) {
+            throw new AuthorizationDeniedException("팔로우 내역이 존재하지 않습니다.");
+        }
+
+        Follow follow = followRepository.findByFollower_UserIdAndFollowee_UserId(followerId, followeeId)
+                .orElseThrow(() -> new FollowNotFoundException("FollowerId : " + followerId + ", FolloweeId : " + followeeId));
+
+        followRepository.delete(follow);
+
+        return DeleteFollowResponse.from(followerId, followeeId);
+    }
+
+    private User getUser(int userId) {
+        return userRepository.findById(userId)
+                .orElseThrow(() -> new UserNotFoundException(String.valueOf(userId), "User"));
+    }
 }

src/main/java/com/codeit/todo/web/controller/FollowController.java

@@ -3,17 +3,18 @@
 import com.codeit.todo.repository.CustomUserDetails;
 import com.codeit.todo.service.follow.FollowService;
 import com.codeit.todo.web.dto.request.follow.ReadFollowRequest;
-import com.codeit.todo.web.dto.request.todo.ReadTodoCompleteWithGoalRequest;
 import com.codeit.todo.web.dto.response.Response;
+import com.codeit.todo.web.dto.response.follow.CreateFollowResponse;
+import com.codeit.todo.web.dto.response.follow.DeleteFollowResponse;
 import com.codeit.todo.web.dto.response.follow.ReadFollowResponse;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import jakarta.validation.Valid;
 import lombok.RequiredArgsConstructor;
 import org.springframework.data.domain.Slice;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.ModelAttribute;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.bind.annotation.*;
 
 @RestController
 @RequiredArgsConstructor
@@ -23,6 +24,10 @@ public class FollowController {
     private final FollowService followService;
 
 
+    @Operation(summary = "팔로우의 최근 등록한 인증글 목록 조회", description = "팔로우의 최근 등록한 인증글 목록 조회 API")
+    @ApiResponses(value = {
+            @ApiResponse(responseCode = "200", description = "조회 성공")
+    })
     @GetMapping
     public Response<Slice<ReadFollowResponse>> getFollows(
             @AuthenticationPrincipal CustomUserDetails userDetails,
@@ -32,4 +37,30 @@ public Response<Slice<ReadFollowResponse>> getFollows(
         int userId = userDetails.getUserId();
         return Response.ok(followService.readFollows(userId, request));
     }
+
+    @Operation(summary = "팔로우 등록", description = "팔로우 등록 API")
+    @ApiResponses(value = {
+            @ApiResponse(responseCode = "200", description = "조회 성공")
+    })
+    @PostMapping("{followerId}")
+    public Response<CreateFollowResponse> createFollow(
+            @AuthenticationPrincipal CustomUserDetails userDetails,
+            @PathVariable int followerId
+    ) {
+        int followeeId = userDetails.getUserId();
+        return Response.ok(followService.registerFollow(followerId, followeeId));
+    }
+
+    @Operation(summary = "팔로우 취소", description = "팔로우 취소 API")
+    @ApiResponses(value = {
+            @ApiResponse(responseCode = "200", description = "조회 성공")
+    })
+    @DeleteMapping("{followerId}")
+    public Response<DeleteFollowResponse> cancelFollow(
+            @AuthenticationPrincipal CustomUserDetails userDetails,
+            @PathVariable int followerId
+    ) {
+        int followeeId = userDetails.getUserId();
+        return Response.ok(followService.cancelFollow(followerId, followeeId));
+    }
 }

src/main/java/com/codeit/todo/web/dto/response/follow/CreateFollowResponse.java

@@ -0,0 +1,15 @@
+package com.codeit.todo.web.dto.response.follow;
+
+import com.codeit.todo.domain.Follow;
+import lombok.Builder;
+
+@Builder
+public record CreateFollowResponse(
+        int followId
+) {
+    public static CreateFollowResponse fromEntity(Follow follow) {
+        return CreateFollowResponse.builder()
+                .followId(follow.getFollowId())
+                .build();
+    }
+}

src/main/java/com/codeit/todo/web/dto/response/follow/DeleteFollowResponse.java

@@ -0,0 +1,13 @@
+package com.codeit.todo.web.dto.response.follow;
+
+import lombok.Builder;
+
+@Builder
+public record DeleteFollowResponse(int followerId, int followeeId) {
+    public static DeleteFollowResponse from(int followerId, int followeeId) {
+        return DeleteFollowResponse.builder()
+                .followerId(followerId)
+                .followeeId(followeeId)
+                .build();
+    }
+}