delete comment

src/main/java/io/spring/api/CommentsApi.java

@@ -2,7 +2,9 @@ package io.spring.api;
 
 import com.fasterxml.jackson.annotation.JsonRootName;
 import io.spring.api.exception.InvalidRequestException;
+import io.spring.api.exception.NoAuthorizationException;
 import io.spring.api.exception.ResourceNotFoundException;
+import io.spring.application.AuthorizationService;
 import io.spring.application.comment.CommentData;
 import io.spring.application.comment.CommentQueryService;
 import io.spring.core.article.Article;
@@ -22,6 +24,7 @@ import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.RestController;
 
 import javax.validation.Valid;
@@ -70,6 +73,20 @@ public class CommentsApi {
         }});
     }
 
+    @RequestMapping(path = "{id}", method = RequestMethod.DELETE)
+    public ResponseEntity deleteComment(@PathVariable("slug") String slug,
+                                        @PathVariable("id") String commentId,
+                                        @AuthenticationPrincipal User user) {
+        Article article = findArticle(slug);
+        return commentRepository.findById(article.getId(), commentId).map(comment -> {
+            if (!AuthorizationService.canWriteComment(user, article, comment)) {
+                throw new NoAuthorizationException();
+            }
+            commentRepository.remove(comment);
+            return ResponseEntity.noContent().build();
+        }).orElseThrow(ResourceNotFoundException::new);
+    }
+
     private Article findArticle(String slug) {
         return articleRepository.findBySlug(slug).map(article -> article).orElseThrow(ResourceNotFoundException::new);
     }

src/main/java/io/spring/application/AuthorizationService.java

@@ -1,10 +1,15 @@
 package io.spring.application;
 
 import io.spring.core.article.Article;
+import io.spring.core.comment.Comment;
 import io.spring.core.user.User;
 
 public class AuthorizationService {
     public static boolean canWriteArticle(User user, Article article) {
         return user.getId().equals(article.getUserId());
     }
+
+    public static boolean canWriteComment(User user, Article article, Comment comment) {
+        return user.getId().equals(article.getUserId()) || user.getId().equals(comment.getUserId());
+    }
 }

src/main/java/io/spring/core/comment/CommentRepository.java

@@ -5,5 +5,7 @@ import java.util.Optional;
 public interface  CommentRepository {
     void save(Comment comment);
 
-    Optional<Comment> findById(String id);
+    Optional<Comment> findById(String articleId, String id);
+
+    void remove(Comment comment);
 }

src/main/java/io/spring/infrastructure/comment/CommentMapper.java

@@ -10,5 +10,7 @@ import org.springframework.stereotype.Component;
 public interface CommentMapper {
     void insert(@Param("comment") Comment comment);
 
-    Comment findById(@Param("id") String id);
+    Comment findById(@Param("articleId") String articleId, @Param("id") String id);
+
+    void delete(@Param("id") String id);
 }

src/main/java/io/spring/infrastructure/comment/MyBatisCommentRepository.java

@@ -22,7 +22,12 @@ public class MyBatisCommentRepository implements CommentRepository {
     }
 
     @Override
-    public Optional<Comment> findById(String id) {
-        return Optional.ofNullable(commentMapper.findById(id));
+    public Optional<Comment> findById(String articleId, String id) {
+        return Optional.ofNullable(commentMapper.findById(articleId, id));
+    }
+
+    @Override
+    public void remove(Comment comment) {
+        commentMapper.delete(comment.getId());
     }
 }