Complete cc.ryanc.halo.web.controller.portal.api.TagController.listPostsBy api

src/main/java/cc/ryanc/halo/service/PostTagService.java

@@ -5,6 +5,8 @@ import cc.ryanc.halo.model.entity.Post;
 import cc.ryanc.halo.model.entity.PostTag;
 import cc.ryanc.halo.model.entity.Tag;
 import cc.ryanc.halo.service.base.CrudService;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.lang.NonNull;
 import org.springframework.lang.Nullable;
@@ -58,6 +60,15 @@ public interface PostTagService extends CrudService<PostTag, Integer> {
     @NonNull
     List<Post> listPostsBy(@NonNull Integer tagId);
 
+    /**
+     * Pages posts by tag id.
+     *
+     * @param tagId    must not be null
+     * @param pageable must not be null
+     * @return a page of post
+     */
+    Page<Post> pagePostsBy(@NonNull Integer tagId, Pageable pageable);
+
     /**
      * Merges or creates post tags by post id and tag id set if absent.
      *

src/main/java/cc/ryanc/halo/service/TagService.java

@@ -21,7 +21,8 @@ public interface TagService extends CrudService<Tag, Integer> {
      * @param slugName slug name
      * @return Tag
      */
-    Tag getBySlugName(@NonNull String slugName);
+    @NonNull
+    Tag getBySlugNameOfNonNull(@NonNull String slugName);
 
     /**
      * Converts to tag output dtos.

src/main/java/cc/ryanc/halo/service/impl/PostTagServiceImpl.java

@@ -11,6 +11,8 @@ import cc.ryanc.halo.repository.TagRepository;
 import cc.ryanc.halo.service.PostTagService;
 import cc.ryanc.halo.service.base.AbstractCrudService;
 import cc.ryanc.halo.utils.ServiceUtils;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.stereotype.Service;
 import org.springframework.util.Assert;
@@ -111,6 +113,17 @@ public class PostTagServiceImpl extends AbstractCrudService<PostTag, Integer> im
         return postRepository.findAllById(postIds);
     }
 
+    @Override
+    public Page<Post> pagePostsBy(Integer tagId, Pageable pageable) {
+        Assert.notNull(tagId, "Tag id must not be null");
+        Assert.notNull(pageable, "Page info must not be null");
+
+        // Find all post ids
+        Set<Integer> postIds = postTagRepository.findAllPostIdsByTagId(tagId);
+
+        return postRepository.findAllByIdIn(postIds, pageable);
+    }
+
     @Override
     public List<PostTag> mergeOrCreateByIfAbsent(Integer postId, Set<Integer> tagIds) {
         Assert.notNull(postId, "Post id must not be null");

src/main/java/cc/ryanc/halo/service/impl/TagServiceImpl.java

@@ -55,7 +55,7 @@ public class TagServiceImpl extends AbstractCrudService<Tag, Integer> implements
      * @return Tag
      */
     @Override
-    public Tag getBySlugName(String slugName) {
+    public Tag getBySlugNameOfNonNull(String slugName) {
         return tagRepository.getBySlugName(slugName).orElseThrow(() -> new NotFoundException("The tag does not exist").setErrorData(slugName));
     }
 

src/main/java/cc/ryanc/halo/web/controller/content/ContentTagController.java

@@ -79,7 +79,7 @@ public class ContentTagController extends BaseContentController {
                        @PathVariable("slugName") String slugName,
                        @PathVariable("page") Integer page,
                        @SortDefault(sort = "postDate", direction = DESC) Sort sort) {
-        final Tag tag = tagService.getBySlugName(slugName);
+        final Tag tag = tagService.getBySlugNameOfNonNull(slugName);
         if (null == tag) {
             return this.renderNotFound();
         }

src/main/java/cc/ryanc/halo/web/controller/portal/api/TagController.java

@@ -1,18 +1,22 @@
 package cc.ryanc.halo.web.controller.portal.api;
 
 import cc.ryanc.halo.model.dto.TagOutputDTO;
+import cc.ryanc.halo.model.dto.post.PostSimpleOutputDTO;
+import cc.ryanc.halo.model.entity.Tag;
 import cc.ryanc.halo.service.PostTagService;
 import cc.ryanc.halo.service.TagService;
 import io.swagger.annotations.ApiOperation;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
+import org.springframework.data.web.PageableDefault;
 import org.springframework.data.web.SortDefault;
-import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.*;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RequestParam;
-import org.springframework.web.bind.annotation.RestController;
 
 import java.util.List;
 
+import static org.springframework.data.domain.Sort.Direction.DESC;
+
 /**
  * Portal tag controller.
  *
@@ -34,7 +38,7 @@ public class TagController {
 
     @GetMapping
     @ApiOperation("Lists tags")
-    public List<? extends TagOutputDTO> listTags(@SortDefault(sort = "updateTime", direction = Sort.Direction.DESC) Sort sort,
+    public List<? extends TagOutputDTO> listTags(@SortDefault(sort = "updateTime", direction = DESC) Sort sort,
                                                  @RequestParam(name = "more", required = false, defaultValue = "false") Boolean more) {
         if (more) {
             return postTagService.listTagWithCountDtos(sort);
@@ -42,4 +46,14 @@ public class TagController {
         return tagService.convertTo(tagService.listAll(sort));
     }
 
+    @GetMapping("{slugName}/posts")
+    @ApiOperation("Lists posts by tag slug name")
+    public Page<PostSimpleOutputDTO> listPostsBy(@PathVariable("slugName") String slugName,
+                                                 @PageableDefault(sort = "updateTime", direction = DESC) Pageable pageable) {
+        // Get tag by slug name
+        Tag tag = tagService.getBySlugNameOfNonNull(slugName);
+
+        // Get posts, convert and return
+        return postTagService.pagePostsBy(tag.getId(), pageable).map(post -> new PostSimpleOutputDTO().convertFrom(post));
+    }
 }