新增主题信息获取功能，完善 Discourse 同步机制

- 在 DiscourseAPI 中添加 fetchTopicInfo 和 fetchTopicTags 方法
- 更新发布流程，支持从 Discourse 同步最新标签和分类信息
- 在更新帖子时自动获取并同步 Discourse 上的标签和分类
- 扩展 Front Matter，新增 discourse_category_id 和 discourse_category 字段
- 优化更新逻辑，确保本地文件与 Discourse 内容保持一致

src/api.ts

@@ -387,4 +387,46 @@ export class DiscourseAPI {
             };
         }
     }
+
+    // 获取特定主题的标签和分类信息
+    async fetchTopicInfo(topicId: number): Promise<{ tags: string[], categoryId?: number }> {
+        try {
+            const url = `${this.settings.baseUrl}/t/${topicId}.json`;
+            const headers = {
+                "Api-Key": this.settings.apiKey,
+                "Api-Username": this.settings.disUser,
+            };
+            
+            const response = await requestUrl({
+                url,
+                method: "GET",
+                headers,
+                throw: false
+            });
+            
+            if (response.status === 200) {
+                const data = response.json;
+                return {
+                    tags: data?.tags || [],
+                    categoryId: data?.category_id
+                };
+            }
+            
+            return { tags: [] };
+        } catch (error) {
+            new NotifyUser(this.app, `Exception while fetching topic info: ${error}`).open();
+            return { tags: [] };
+        }
+    }
+
+    // 获取特定主题的标签
+    async fetchTopicTags(topicId: number): Promise<string[]> {
+        try {
+            const topicInfo = await this.fetchTopicInfo(topicId);
+            return topicInfo.tags;
+        } catch (error) {
+            new NotifyUser(this.app, `Exception while fetching topic tags: ${error}`).open();
+            return [];
+        }
+    }
 } 

src/main.ts

@@ -94,12 +94,15 @@ export default class PublishToDiscourse extends Plugin implements PluginInterfac
 		// 使用expandEmbeds处理嵌入内容
 		const content = await expandEmbeds(this.app, targetFile);
 		const fm = getFrontMatter(content);
+		const postId = fm?.discourse_post_id;
+		const topicId = fm?.discourse_topic_id;
+		const isUpdate = postId !== undefined && topicId !== undefined;
 		
 		// 初始化activeFile对象
 		this.activeFile = {
 			name: targetFile.basename,
 			content: content,
-			postId: fm?.discourse_post_id,
+			postId: postId,
 			// 从frontmatter中获取标签，如果没有则使用空数组
 			tags: fm?.discourse_tags || []
 		};
@@ -110,6 +113,32 @@ export default class PublishToDiscourse extends Plugin implements PluginInterfac
 			this.api.fetchTags()
 		]);
 		
+		// 如果是更新帖子，先从Discourse获取最新标签和分类
+		if (isUpdate) {
+			try {
+				const topicInfo = await this.api.fetchTopicInfo(topicId);
+				
+				// 用Discourse上的标签覆盖本地标签
+				if (topicInfo.tags.length > 0) {
+					this.activeFile.tags = topicInfo.tags;
+					console.log(`Updated tags from Discourse: ${topicInfo.tags.join(', ')}`);
+				}
+				
+				// 如果获取到了分类ID，更新设置中的分类
+				if (topicInfo.categoryId) {
+					// 查找分类名称
+					const category = categories.find(c => c.id === topicInfo.categoryId);
+					if (category) {
+						this.settings.category = category.id;
+						console.log(`Updated category from Discourse: ${category.name} (${category.id})`);
+					}
+				}
+			} catch (error) {
+				console.error("Failed to fetch topic info from Discourse:", error);
+				// 如果获取失败，继续使用本地标签和分类
+			}
+		}
+		
 		if (categories.length > 0) {
 			new SelectCategoryModal(this.app, this, categories, tags).open();
 		}
@@ -219,6 +248,13 @@ export default class PublishToDiscourse extends Plugin implements PluginInterfac
 			const fm = getFrontMatter(content);
 			const discourseUrl = `${this.settings.baseUrl}/t/${topicId}`;
 			
+			// 获取当前分类信息
+			const categoryId = this.settings.category;
+			// 查找分类名称
+			const categories = await this.api.fetchCategories();
+			const category = categories.find(c => c.id === categoryId);
+			const categoryName = category ? category.name : '';
+			
 			let newContent: string;
 			if (fm) {
 				// 更新现有Front Matter
@@ -227,7 +263,9 @@ export default class PublishToDiscourse extends Plugin implements PluginInterfac
 					discourse_post_id: postId, 
 					discourse_topic_id: topicId,
 					discourse_url: discourseUrl,
-					discourse_tags: tags
+					discourse_tags: tags,
+					discourse_category_id: categoryId,
+					discourse_category: categoryName
 				};
 				newContent = content.replace(/^---\n[\s\S]*?\n---\n/, `---\n${yaml.stringify(updatedFm)}---\n`);
 			} else {
@@ -236,7 +274,9 @@ export default class PublishToDiscourse extends Plugin implements PluginInterfac
 					discourse_post_id: postId, 
 					discourse_topic_id: topicId,
 					discourse_url: discourseUrl,
-					discourse_tags: tags
+					discourse_tags: tags,
+					discourse_category_id: categoryId,
+					discourse_category: categoryName
 				};
 				newContent = `---\n${yaml.stringify(newFm)}---\n${content}`;
 			}