#24 simple sns: 좋아요 api

simple_sns/src/main/java/com/example/sns/controller/PostController.java

@@ -54,4 +54,11 @@ public class PostController {
     public Response<Page<PostResponse>> my(Pageable pageable, Authentication authentication) {
         return Response.success(postService.my(authentication.getName(), pageable).map(PostResponse::fromPost));
     }
+
+    @PostMapping("/{postId}/likes")
+    public Response<Void> like(@PathVariable Integer postId, Authentication authentication) {
+        postService.like(postId, authentication.getName());
+        return Response.success();
+    }
+
 }

simple_sns/src/main/java/com/example/sns/exception/ErrorCode.java

@@ -14,7 +14,8 @@ public enum ErrorCode {
     INVALID_TOKEN(HttpStatus.UNAUTHORIZED, "Token is invalid."),
     POST_NOT_FOUND(HttpStatus.NOT_FOUND, "Post not founded."),
     INVALID_PERMISSION(HttpStatus.UNAUTHORIZED, "Permission is invalid."),
-    INTERNAL_SERVER_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "Internal server error.")
+    INTERNAL_SERVER_ERROR(HttpStatus.INTERNAL_SERVER_ERROR, "Internal server error."),
+    ALREADY_LIKED(HttpStatus.CONFLICT, "User already liked the post."),
 
     ;
 

simple_sns/src/main/java/com/example/sns/model/entity/LikeEntity.java

@@ -0,0 +1,54 @@
+package com.example.sns.model.entity;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.hibernate.annotations.SQLDelete;
+import org.hibernate.annotations.Where;
+
+import javax.persistence.*;
+import java.sql.Timestamp;
+import java.time.Instant;
+
+@Entity
+@Table(name = "likes")
+@Getter
+@Setter
+@SQLDelete(sql = "UPDATE likes SET deleted_at = NOW() where id=?")
+@Where(clause = "deleted_at IS NULL")
+public class LikeEntity {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Integer id;
+
+    @ManyToOne
+    @JoinColumn(name = "user_id")
+    private UserEntity user;
+
+    @ManyToOne
+    @JoinColumn(name = "post_id")
+    private PostEntity post;
+
+    private Timestamp registeredAt;
+    private Timestamp updatedAt;
+
+    @Column(name = "deleted_at")
+    private Timestamp deletedAt;
+
+    @PrePersist
+    void registeredAt() {
+        this.registeredAt = Timestamp.from(Instant.now());
+    }
+
+    @PreUpdate
+    void updatedAt() {
+        this.updatedAt = Timestamp.from(Instant.now());
+    }
+
+    public static LikeEntity of(UserEntity userEntity, PostEntity postEntity) {
+        LikeEntity entity = new LikeEntity();
+        entity.setUser(userEntity);
+        entity.setPost(postEntity);
+        return entity;
+    }
+}

simple_sns/src/main/java/com/example/sns/repository/LikeEntityRepository.java

@@ -0,0 +1,15 @@
+package com.example.sns.repository;
+
+import com.example.sns.model.entity.LikeEntity;
+import com.example.sns.model.entity.PostEntity;
+import com.example.sns.model.entity.UserEntity;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.util.Optional;
+
+@Repository
+public interface LikeEntityRepository extends JpaRepository<LikeEntity, Integer> {
+
+    Optional<LikeEntity> findByUserAndPost(UserEntity user, PostEntity post);
+}

simple_sns/src/main/java/com/example/sns/service/PostService.java

@@ -2,8 +2,10 @@ package com.example.sns.service;
 
 import com.example.sns.exception.SnsApplicationException;
 import com.example.sns.model.Post;
+import com.example.sns.model.entity.LikeEntity;
 import com.example.sns.model.entity.PostEntity;
 import com.example.sns.model.entity.UserEntity;
+import com.example.sns.repository.LikeEntityRepository;
 import com.example.sns.repository.PostEntityRepository;
 import com.example.sns.repository.UserEntityRepository;
 import lombok.RequiredArgsConstructor;
@@ -20,6 +22,7 @@ public class PostService {
 
     private final PostEntityRepository postEntityRepository;
     private final UserEntityRepository userEntityRepository;
+    private final LikeEntityRepository likeEntityRepository;
 
     @Transactional
     public void create(String title, String body, String username) {
@@ -107,4 +110,35 @@ public class PostService {
                 );
         return postEntityRepository.findAllByUser(userEntity, pageable).map(Post::fromEntity);
     }
+
+    @Transactional
+    public void like(Integer postId, String username) {
+        PostEntity postEntity = postEntityRepository.findById(postId)
+                .orElseThrow(
+                        () -> new SnsApplicationException(
+                                POST_NOT_FOUND,
+                                String.format("%s not founded", postId)
+                        )
+                );
+
+        UserEntity userEntity = userEntityRepository.findByUsername(username)
+                .orElseThrow(
+                        () -> new SnsApplicationException(
+                                USER_NOT_FOUND,
+                                String.format("%s not founded", username)
+                        )
+                );
+
+        // check liked
+        likeEntityRepository.findByUserAndPost(userEntity, postEntity)
+                .ifPresent(it -> {
+                    throw new SnsApplicationException(
+                            ALREADY_LIKED,
+                            String.format("username %s already like post %d", username, postId)
+                    );
+                });
+
+        // save like
+        likeEntityRepository.save(LikeEntity.of(userEntity, postEntity));
+    }
 }

simple_sns/src/test/java/com/example/sns/controller/PostControllerTest.java

@@ -226,4 +226,36 @@ public class PostControllerTest {
                 ).andDo(print())
                 .andExpect(status().isUnauthorized());
     }
+
+    @Test
+    @WithMockUser
+    void 좋아요기능() throws Exception {
+
+        mockMvc.perform(post("/api/v1/posts/1/likes")
+                        .contentType(MediaType.APPLICATION_JSON)
+                ).andDo(print())
+                .andExpect(status().isOk());
+    }
+
+    @Test
+    @WithAnonymousUser
+    void 좋아요버튼클릭시_로그인하지_않은경우() throws Exception {
+
+        mockMvc.perform(post("/api/v1/posts/1/likes")
+                        .contentType(MediaType.APPLICATION_JSON)
+                ).andDo(print())
+                .andExpect(status().isUnauthorized());
+    }
+
+    @Test
+    @WithMockUser
+    void 좋아요버튼클릭시_게시글이_없는경우() throws Exception {
+
+        doThrow(new SnsApplicationException(ErrorCode.POST_NOT_FOUND)).when(postService).like(any(), any());
+
+        mockMvc.perform(post("/api/v1/posts/1/likes")
+                        .contentType(MediaType.APPLICATION_JSON)
+                ).andDo(print())
+                .andExpect(status().isNotFound());
+    }
 }