Refactor MarkdownUtils.

build.gradle

@@ -56,6 +56,10 @@ dependencies {
     implementation 'com.atlassian.commonmark:commonmark:0.12.1'
     implementation 'com.atlassian.commonmark:commonmark-ext-gfm-tables:0.12.1'
     implementation 'com.atlassian.commonmark:commonmark-ext-yaml-front-matter:0.12.1'
+    implementation 'com.atlassian.commonmark:commonmark-ext-autolink:0.12.1'
+    implementation 'com.atlassian.commonmark:commonmark-ext-gfm-strikethrough:0.12.1'
+    implementation 'com.atlassian.commonmark:commonmark-ext-heading-anchor:0.12.1'
+    implementation 'com.atlassian.commonmark:commonmark-ext-ins:0.12.1'
     implementation 'io.springfox:springfox-swagger2:2.9.2'
     implementation 'io.springfox:springfox-swagger-ui:2.9.2'
     implementation 'org.apache.commons:commons-lang3:3.8.1'

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

@@ -2,9 +2,13 @@ package run.halo.app.utils;
 
 import org.apache.commons.lang3.StringUtils;
 import org.commonmark.Extension;
+import org.commonmark.ext.autolink.AutolinkExtension;
 import org.commonmark.ext.front.matter.YamlFrontMatterExtension;
 import org.commonmark.ext.front.matter.YamlFrontMatterVisitor;
+import org.commonmark.ext.gfm.strikethrough.StrikethroughExtension;
 import org.commonmark.ext.gfm.tables.TablesExtension;
+import org.commonmark.ext.heading.anchor.HeadingAnchorExtension;
+import org.commonmark.ext.ins.InsExtension;
 import org.commonmark.node.Node;
 import org.commonmark.parser.Parser;
 import org.commonmark.renderer.html.HtmlRenderer;
@@ -26,30 +30,73 @@ import java.util.Set;
  */
 public class MarkdownUtils {
 
-    /**
-     * Front-matter extension
-     */
-    private static final Set<Extension> EXTENSIONS_YAML = Collections.singleton(YamlFrontMatterExtension.create());
 
     /**
-     * Table extension
+     * commonmark-java extension for autolinking
      */
-    private static final Set<Extension> EXTENSIONS_TABLE = Collections.singleton(TablesExtension.create());
+    private static final Set<Extension> EXTENSIONS_AUTO_LINK = Collections.singleton(AutolinkExtension.create());
+
+    /**
+     * commonmark-java extension for strikethrough
+     */
+    private static final Set<Extension> EXTENSIONS_STRIKETHROUGH = Collections.singleton(StrikethroughExtension.create());
+
+    /**
+     * commonmark-java extension for tables
+     */
+    private static final Set<Extension> EXTENSIONS_TABLES = Collections.singleton(TablesExtension.create());
+
+    /**
+     * commonmark-java extension for adding id attributes to h tags
+     */
+    private static final Set<Extension> EXTENSIONS_HEADING_ANCHOR = Collections.singleton(HeadingAnchorExtension.create());
+
+    /**
+     * commonmark-java extension for &lt;ins&gt; (underline)
+     */
+    private static final Set<Extension> EXTENSIONS_INS = Collections.singleton(InsExtension.create());
+
+    /**
+     * commonmark-java extension for YAML front matter
+     */
+    private static final Set<Extension> EXTENSIONS_YAML_FRONT_MATTER = Collections.singleton(YamlFrontMatterExtension.create());
+
 
     /**
      * Parse Markdown content
      */
-    private static final Parser PARSER = Parser.builder().extensions(EXTENSIONS_YAML).extensions(EXTENSIONS_TABLE).build();
+    private static final Parser PARSER = Parser.builder()
+            .extensions(EXTENSIONS_AUTO_LINK)
+            .extensions(EXTENSIONS_STRIKETHROUGH)
+            .extensions(EXTENSIONS_TABLES)
+            .extensions(EXTENSIONS_HEADING_ANCHOR)
+            .extensions(EXTENSIONS_INS)
+            .extensions(EXTENSIONS_YAML_FRONT_MATTER)
+            .build();
 
     /**
      * Render HTML content
      */
-    private static final HtmlRenderer RENDERER = HtmlRenderer.builder().extensions(EXTENSIONS_YAML).extensions(EXTENSIONS_TABLE).build();
+    private static final HtmlRenderer RENDERER = HtmlRenderer.builder()
+            .extensions(EXTENSIONS_AUTO_LINK)
+            .extensions(EXTENSIONS_STRIKETHROUGH)
+            .extensions(EXTENSIONS_TABLES)
+            .extensions(EXTENSIONS_HEADING_ANCHOR)
+            .extensions(EXTENSIONS_INS)
+            .extensions(EXTENSIONS_YAML_FRONT_MATTER)
+            .build();
 
     /**
      * Render text content
      */
-    private static final TextContentRenderer TEXT_CONTENT_RENDERER = TextContentRenderer.builder().extensions(EXTENSIONS_YAML).extensions(EXTENSIONS_TABLE).build();
+    private static final TextContentRenderer TEXT_CONTENT_RENDERER = TextContentRenderer.builder()
+            .extensions(EXTENSIONS_AUTO_LINK)
+            .extensions(EXTENSIONS_STRIKETHROUGH)
+            .extensions(EXTENSIONS_TABLES)
+            .extensions(EXTENSIONS_HEADING_ANCHOR)
+            .extensions(EXTENSIONS_INS)
+            .extensions(EXTENSIONS_YAML_FRONT_MATTER)
+            .build();
 
     /**
      * Render Markdown content
@@ -59,20 +106,25 @@ public class MarkdownUtils {
      * @see <a href="https://github.com/otale/tale/blob/master/src/main/java/com/tale/utils/TaleUtils.java">TaleUtils.java</a>
      */
     public static String renderMarkdown(String content) {
+
         final Node document = PARSER.parse(content);
         String renderContent = RENDERER.render(document);
+
         // render netease music short url
         if (content.contains(HaloConst.NETEASE_MUSIC_PREFIX)) {
             renderContent = content.replaceAll(HaloConst.NETEASE_MUSIC_REG_PATTERN, HaloConst.NETEASE_MUSIC_IFRAME);
         }
+
         // render bilibili video short url
         if (content.contains(HaloConst.BILIBILI_VIDEO_PREFIX)) {
             renderContent = content.replaceAll(HaloConst.BILIBILI_VIDEO_REG_PATTERN, HaloConst.BILIBILI_VIDEO_IFRAME);
         }
+
         // render youtube video short url
         if (content.contains(HaloConst.YOUTUBE_VIDEO_PREFIX)) {
             renderContent = content.replaceAll(HaloConst.YOUTUBE_VIDEO_REG_PATTERN, HaloConst.YOUTUBE_VIDEO_IFRAME);
         }
+
         return renderContent;
     }
 
@@ -84,6 +136,7 @@ public class MarkdownUtils {
      */
     @NonNull
     public static String renderText(@Nullable String markdownContent) {
+
         if (StringUtils.isBlank(markdownContent)) {
             return "";
         }