Support post and sheet export.

src/main/java/run/halo/app/service/PostService.java

@@ -106,6 +106,24 @@ public interface PostService extends BasePostService<Post> {
     @NonNull
     Post importMarkdown(@NonNull String markdown);
 
+    /**
+     * Export post to markdown file by post id.
+     *
+     * @param id post id
+     * @return markdown file content
+     */
+    @NonNull
+    String exportMarkdown(@NonNull Integer id);
+
+    /**
+     * Export post to markdown file by post.
+     *
+     * @param post current post
+     * @return markdown file content
+     */
+    @NonNull
+    String exportMarkdown(@NonNull Post post);
+
     /**
      * Converts to detail vo.
      *

src/main/java/run/halo/app/service/SheetService.java

@@ -54,6 +54,24 @@ public interface SheetService extends BasePostService<Sheet> {
     @NonNull
     Sheet importMarkdown(@NonNull String markdown);
 
+    /**
+     * Export sheet to markdown file by sheet id.
+     *
+     * @param id sheet id
+     * @return markdown file content
+     */
+    @NonNull
+    String exportMarkdown(@NonNull Integer id);
+
+    /**
+     * Export sheet to markdown file by sheet.
+     *
+     * @param sheet current sheet
+     * @return markdown file content
+     */
+    @NonNull
+    String exportMarkdown(@NonNull Sheet sheet);
+
     /**
      * Converts to list dto page.
      *

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

@@ -1,5 +1,6 @@
 package run.halo.app.service.impl;
 
+import cn.hutool.core.text.StrBuilder;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.context.ApplicationEventPublisher;
@@ -286,6 +287,51 @@ public class PostServiceImpl extends BasePostServiceImpl<Post> implements PostSe
         return null;
     }
 
+    @Override
+    public String exportMarkdown(Integer id) {
+        Assert.notNull(id, "Post id must not be null");
+        Post post = getById(id);
+        return exportMarkdown(post);
+    }
+
+    @Override
+    public String exportMarkdown(Post post) {
+        Assert.notNull(post, "Post must not be null");
+
+        StrBuilder content = new StrBuilder("---\n");
+
+        content.append("type: ").append("post").append("\n");
+        content.append("title: ").append(post.getTitle()).append("\n");
+        content.append("permalink: ").append(post.getUrl()).append("\n");
+        content.append("thumbnail: ").append(post.getThumbnail()).append("\n");
+        content.append("status: ").append(post.getStatus()).append("\n");
+        content.append("date: ").append(post.getCreateTime()).append("\n");
+        content.append("updated: ").append(post.getEditTime()).append("\n");
+        content.append("comments: ").append(!post.getDisallowComment()).append("\n");
+
+        List<Tag> tags = postTagService.listTagsBy(post.getId());
+
+        if (tags.size() > 0) {
+            content.append("tags:").append("\n");
+            for (Tag tag : tags) {
+                content.append("  - ").append(tag.getName()).append("\n");
+            }
+        }
+
+        List<Category> categories = postCategoryService.listCategoryBy(post.getId());
+
+        if (categories.size() > 0) {
+            content.append("categories:").append("\n");
+            for (Category category : categories) {
+                content.append("  - ").append(category.getName()).append("\n");
+            }
+        }
+
+        content.append("---\n\n");
+        content.append(post.getOriginalContent());
+        return content.toString();
+    }
+
     @Override
     public PostDetailVO convertToDetailVo(Post post) {
         return convertTo(post,

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

@@ -1,5 +1,6 @@
 package run.halo.app.service.impl;
 
+import cn.hutool.core.text.StrBuilder;
 import org.springframework.context.ApplicationEventPublisher;
 import org.springframework.data.domain.Page;
 import org.springframework.data.domain.Pageable;
@@ -108,6 +109,33 @@ public class SheetServiceImpl extends BasePostServiceImpl<Sheet> implements Shee
         return null;
     }
 
+    @Override
+    public String exportMarkdown(Integer id) {
+        Assert.notNull(id, "sheet id must not be null");
+        Sheet sheet = getById(id);
+        return exportMarkdown(sheet);
+    }
+
+    @Override
+    public String exportMarkdown(Sheet sheet) {
+        Assert.notNull(sheet, "Sheet must not be null");
+
+        StrBuilder content = new StrBuilder("---\n");
+
+        content.append("type: ").append("sheet").append("\n");
+        content.append("title: ").append(sheet.getTitle()).append("\n");
+        content.append("permalink: ").append(sheet.getUrl()).append("\n");
+        content.append("thumbnail: ").append(sheet.getThumbnail()).append("\n");
+        content.append("status: ").append(sheet.getStatus()).append("\n");
+        content.append("date: ").append(sheet.getCreateTime()).append("\n");
+        content.append("updated: ").append(sheet.getEditTime()).append("\n");
+        content.append("comments: ").append(!sheet.getDisallowComment()).append("\n");
+
+        content.append("---\n\n");
+        content.append(sheet.getOriginalContent());
+        return content.toString();
+    }
+
     @Override
     public Sheet removeById(Integer id) {
         Sheet sheet = super.removeById(id);

src/test/java/run/halo/app/service/impl/PostServiceImplTest.java

@@ -0,0 +1,24 @@
+package run.halo.app.service.impl;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@ActiveProfiles("dev")
+public class PostServiceImplTest {
+
+    @Autowired
+    private PostServiceImpl postService;
+
+    @Test
+    public void getContent(){
+        String exportMarkdown = postService.exportMarkdown(18);
+        System.out.println(exportMarkdown);
+    }
+}