Return post summary for listing

src/main/java/run/halo/app/service/impl/BasePostServiceImpl.java

@@ -7,6 +7,7 @@ import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.domain.Sort;
 import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.CollectionUtils;
 import run.halo.app.exception.AlreadyExistsException;
@@ -17,7 +18,9 @@ import run.halo.app.model.dto.post.BasePostMinimalDTO;
 import run.halo.app.model.dto.post.BasePostSimpleDTO;
 import run.halo.app.model.entity.BasePost;
 import run.halo.app.model.enums.PostStatus;
+import run.halo.app.model.properties.PostProperties;
 import run.halo.app.repository.base.BasePostRepository;
+import run.halo.app.service.OptionService;
 import run.halo.app.service.base.AbstractCrudService;
 import run.halo.app.service.base.BasePostService;
 import run.halo.app.utils.DateUtils;
@@ -44,9 +47,13 @@ public abstract class BasePostServiceImpl<POST extends BasePost> extends Abstrac
 
     private final BasePostRepository<POST> basePostRepository;
 
-    public BasePostServiceImpl(BasePostRepository<POST> basePostRepository) {
+    private final OptionService optionService;
+
+    public BasePostServiceImpl(BasePostRepository<POST> basePostRepository,
+                               OptionService optionService) {
         super(basePostRepository);
         this.basePostRepository = basePostRepository;
+        this.optionService = optionService;
     }
 
     @Override
@@ -264,7 +271,14 @@ public abstract class BasePostServiceImpl<POST extends BasePost> extends Abstrac
     public BasePostSimpleDTO convertToSimple(POST post) {
         Assert.notNull(post, "Post must not be null");
 
-        return new BasePostSimpleDTO().convertFrom(post);
+        BasePostSimpleDTO basePostSimpleDTO = new BasePostSimpleDTO().convertFrom(post);
+
+        // Set summary
+        if (StringUtils.isBlank(basePostSimpleDTO.getSummary())) {
+            basePostSimpleDTO.setSummary(convertToSummary(post.getOriginalContent()));
+        }
+
+        return basePostSimpleDTO;
     }
 
     @Override
@@ -331,4 +345,17 @@ public abstract class BasePostServiceImpl<POST extends BasePost> extends Abstrac
             throw new AlreadyExistsException("The post url " + post.getUrl() + " has been exist");
         }
     }
+
+    @NonNull
+    protected String convertToSummary(@Nullable String markdownContent) {
+        // Render text content
+        String textContent = MarkdownUtils.renderText(markdownContent);
+
+        // Get summary length
+        Integer summaryLength = optionService.getByPropertyOrDefault(PostProperties.SUMMARY_LENGTH, Integer.class, 150);
+
+        // Set summary
+        return StringUtils.substring(textContent, 0, summaryLength);
+    }
+
 }

src/main/java/run/halo/app/service/impl/PostServiceImpl.java

@@ -67,8 +67,9 @@ public class PostServiceImpl extends BasePostServiceImpl<Post> implements PostSe
                            PostTagService postTagService,
                            PostCategoryService postCategoryService,
                            PostCommentService postCommentService,
-                           ApplicationEventPublisher eventPublisher) {
+                           ApplicationEventPublisher eventPublisher,
-        super(postRepository);
+                           OptionService optionService) {
+        super(postRepository, optionService);
         this.postRepository = postRepository;
         this.tagService = tagService;
         this.categoryService = categoryService;
@@ -333,6 +334,11 @@ public class PostServiceImpl extends BasePostServiceImpl<Post> implements PostSe
         return postPage.map(post -> {
             PostListVO postListVO = new PostListVO().convertFrom(post);
 
+            if (StringUtils.isBlank(postListVO.getSummary())) {
+                // Set summary
+                postListVO.setSummary(convertToSummary(post.getOriginalContent()));
+            }
+
             Optional.ofNullable(tagListMap.get(post.getId())).orElseGet(LinkedList::new);
 
             // Set tags

src/main/java/run/halo/app/service/impl/SheetServiceImpl.java

@@ -10,6 +10,7 @@ import run.halo.app.model.entity.Sheet;
 import run.halo.app.model.enums.PostStatus;
 import run.halo.app.model.vo.SheetListVO;
 import run.halo.app.repository.SheetRepository;
+import run.halo.app.service.OptionService;
 import run.halo.app.service.SheetCommentService;
 import run.halo.app.service.SheetService;
 import run.halo.app.utils.ServiceUtils;
@@ -35,8 +36,9 @@ public class SheetServiceImpl extends BasePostServiceImpl<Sheet> implements Shee
 
     public SheetServiceImpl(SheetRepository sheetRepository,
                             ApplicationEventPublisher eventPublisher,
-                            SheetCommentService sheetCommentService) {
+                            SheetCommentService sheetCommentService,
-        super(sheetRepository);
+                            OptionService optionService) {
+        super(sheetRepository, optionService);
         this.sheetRepository = sheetRepository;
         this.eventPublisher = eventPublisher;
         this.sheetCommentService = sheetCommentService;

src/main/java/run/halo/app/utils/MarkdownUtils.java

@@ -1,6 +1,6 @@
 package run.halo.app.utils;
 
-import run.halo.app.model.support.HaloConst;
+import org.apache.commons.lang3.StringUtils;
 import org.commonmark.Extension;
 import org.commonmark.ext.front.matter.YamlFrontMatterExtension;
 import org.commonmark.ext.front.matter.YamlFrontMatterVisitor;
@@ -8,6 +8,10 @@ import org.commonmark.ext.gfm.tables.TablesExtension;
 import org.commonmark.node.Node;
 import org.commonmark.parser.Parser;
 import org.commonmark.renderer.html.HtmlRenderer;
+import org.commonmark.renderer.text.TextContentRenderer;
+import org.springframework.lang.NonNull;
+import org.springframework.lang.Nullable;
+import run.halo.app.model.support.HaloConst;
 
 import java.util.Collections;
 import java.util.List;
@@ -42,6 +46,11 @@ public class MarkdownUtils {
      */
     private static final HtmlRenderer RENDERER = HtmlRenderer.builder().extensions(EXTENSIONS_YAML).extensions(EXTENSIONS_TABLE).build();
 
+    /**
+     * Render text content
+     */
+    private static final TextContentRenderer TEXT_CONTENT_RENDERER = TextContentRenderer.builder().extensions(EXTENSIONS_YAML).extensions(EXTENSIONS_TABLE).build();
+
     /**
      * Render Markdown content
      *
@@ -67,6 +76,21 @@ public class MarkdownUtils {
         return renderContent;
     }
 
+    /**
+     * Render text content.
+     *
+     * @param markdownContent markdown content
+     * @return text content or empty string if markdown content is blank
+     */
+    @NonNull
+    public static String renderText(@Nullable String markdownContent) {
+        if (StringUtils.isBlank(markdownContent)) {
+            return "";
+        }
+
+        return TEXT_CONTENT_RENDERER.render(PARSER.parse(markdownContent));
+    }
+
     /**
      * Get front-matter
      *