should update article

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

@@ -1,25 +1,37 @@
 package io.spring.api;
 
+import com.fasterxml.jackson.annotation.JsonRootName;
+import io.spring.api.exception.NoAuthorizationException;
 import io.spring.api.exception.ResourceNotFoundException;
+import io.spring.application.AuthorizationService;
 import io.spring.application.article.ArticleData;
 import io.spring.application.article.ArticleQueryService;
+import io.spring.core.article.ArticleRepository;
 import io.spring.core.user.User;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.ResponseEntity;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestBody;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
+import javax.validation.Valid;
+
 @RestController
 @RequestMapping(path = "/articles/{slug}")
 public class ArticleApi {
     private ArticleQueryService articleQueryService;
+    private ArticleRepository articleRepository;
 
     @Autowired
-    public ArticleApi(ArticleQueryService articleQueryService) {
+    public ArticleApi(ArticleQueryService articleQueryService, ArticleRepository articleRepository) {
         this.articleQueryService = articleQueryService;
+        this.articleRepository = articleRepository;
     }
 
     @GetMapping
@@ -27,4 +39,30 @@ public class ArticleApi {
                                                @AuthenticationPrincipal User user) {
         return articleQueryService.findBySlug(slug, user).map(ResponseEntity::ok).orElseThrow(ResourceNotFoundException::new);
     }
+
+    @PutMapping
+    public ResponseEntity<ArticleData> updateArticle(@PathVariable("slug") String slug,
+                                                     @AuthenticationPrincipal User user,
+                                                     @Valid @RequestBody UpdateArticleParam updateArticleParam) {
+        return articleRepository.findBySlug(slug).map(article -> {
+            if (!AuthorizationService.canUpdateArticle(user, article)) {
+                throw new NoAuthorizationException();
+            }
+            article.update(
+                updateArticleParam.getTitle(),
+                updateArticleParam.getDescription(),
+                updateArticleParam.getBody());
+            articleRepository.save(article);
+            return ResponseEntity.ok(articleQueryService.findBySlug(slug, user).get());
+        }).orElseThrow(ResourceNotFoundException::new);
+    }
+}
+
+@Getter
+@NoArgsConstructor
+@JsonRootName("article")
+class UpdateArticleParam {
+    private String title = "";
+    private String body = "";
+    private String description = "";
 }

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

@@ -41,8 +41,6 @@ public class ArticlesApi {
         }
 
         Article article = new Article(
-            articleRepository.toSlug(
-                newArticleParam.getTitle()),
             newArticleParam.getTitle(),
             newArticleParam.getDescription(),
             newArticleParam.getBody(),

src/main/java/io/spring/api/exception/NoAuthorizationException.java

@@ -0,0 +1,8 @@
+package io.spring.api.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.web.bind.annotation.ResponseStatus;
+
+@ResponseStatus(HttpStatus.FORBIDDEN)
+public class NoAuthorizationException extends RuntimeException {
+}

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

@@ -0,0 +1,10 @@
+package io.spring.application;
+
+import io.spring.core.article.Article;
+import io.spring.core.user.User;
+
+public class AuthorizationService {
+    public static boolean canUpdateArticle(User user, Article article) {
+        return user.getId().equals(article.getUserId());
+    }
+}

src/main/java/io/spring/core/article/Article.java

@@ -26,9 +26,9 @@ public class Article {
     private DateTime createdAt;
     private DateTime updatedAt;
 
-    public Article(String slug, String title, String description, String body, String[] tagList, String userId) {
+    public Article(String title, String description, String body, String[] tagList, String userId) {
         this.id = UUID.randomUUID().toString();
-        this.slug = slug;
+        this.slug = toSlug(title);
         this.title = title;
         this.description = description;
         this.body = body;
@@ -38,4 +38,20 @@ public class Article {
         this.updatedAt = new DateTime();
     }
 
+    public void update(String title, String description, String body) {
+        if (!"".equals(title)) {
+            this.title = title;
+            this.slug = toSlug(title);
+        }
+        if (!"".equals(description)) {
+            this.description = description;
+        }
+        if (!"".equals(body)) {
+            this.body = body;
+        }
+    }
+
+    private String toSlug(String title) {
+        return title.toLowerCase().replace(' ', '-');
+    }
 }

src/main/java/io/spring/core/article/ArticleRepository.java

@@ -3,9 +3,10 @@ package io.spring.core.article;
 import java.util.Optional;
 
 public interface ArticleRepository {
-    String toSlug(String title);
 
     void save(Article article);
 
     Optional<Article> findById(String id);
+
+    Optional<Article> findBySlug(String slug);
 }

src/main/java/io/spring/infrastructure/article/ArticleMapper.java

@@ -18,4 +18,8 @@ public interface ArticleMapper {
     void insertTag(@Param("tag") Tag tag);
 
     void insertArticleTagRelation(@Param("articleId") String articleId, @Param("tagId") String tagId);
+
+    Article findBySlug(@Param("slug") String slug);
+
+    void update(@Param("article") Article article);
 }

src/main/java/io/spring/infrastructure/article/MyBatisArticleRepository.java

@@ -16,12 +16,15 @@ public class MyBatisArticleRepository implements ArticleRepository {
     }
 
     @Override
-    public String toSlug(String title) {
-        return title.toLowerCase().replace(' ', '-');
+    public void save(Article article) {
+        if (articleMapper.findById(article.getId()) == null) {
+            createNew(article);
+        } else {
+            articleMapper.update(article);
+        }
     }
 
-    @Override
-    public void save(Article article) {
+    private void createNew(Article article) {
         articleMapper.insert(article);
         for (Tag tag : article.getTags()) {
             if (!articleMapper.findTag(tag.getName())) {
@@ -35,4 +38,9 @@ public class MyBatisArticleRepository implements ArticleRepository {
     public Optional<Article> findById(String id) {
         return Optional.ofNullable(articleMapper.findById(id));
     }
+
+    @Override
+    public Optional<Article> findBySlug(String slug) {
+        return Optional.ofNullable(articleMapper.findBySlug(slug));
+    }
 }