Upload public.js

backend/src/routes/public.js

@@ -1,6 +1,7 @@
 import express from 'express';
 import githubService from '../services/githubService.js';
 import memoryStorageService from '../services/memoryStorageService.js';
+import screenshotService from '../services/screenshotService.js';
 
 const router = express.Router();
 
@@ -445,6 +446,8 @@ router.post('/generate-share-link', async (req, res, next) => {
       pptUrl: `${protocol}://${baseUrl}/api/public/ppt/${userId}/${pptId}`,
       // 前端查看链接
       viewUrl: `${protocol}://${baseUrl}/public/${userId}/${pptId}/${slideIndex}`,
+      // 新增：截图链接
+      screenshotUrl: `${protocol}://${baseUrl}/api/public/screenshot/${userId}/${pptId}/${slideIndex}`,
       // 添加PPT信息
       pptInfo: {
         id: pptId,
@@ -461,4 +464,71 @@ router.post('/generate-share-link', async (req, res, next) => {
   }
 });
 
+// 截图功能 - 返回JPEG图片
+router.get('/screenshot/:userId/:pptId/:slideIndex?', async (req, res, next) => {
+  try {
+    const { userId, pptId, slideIndex = 0 } = req.params;
+    const slideIdx = parseInt(slideIndex);
+    const fileName = `${pptId}.json`;
+    const storageService = getStorageService();
+
+    let pptData = null;
+    
+    // 获取PPT数据（复用现有逻辑）
+    if (storageService === githubService && storageService.repositories) {
+      for (let i = 0; i < storageService.repositories.length; i++) {
+        try {
+          const result = await storageService.getFile(userId, fileName, i);
+          if (result) {
+            pptData = result.content;
+            break;
+          }
+        } catch (error) {
+          continue;
+        }
+      }
+    } else {
+      const result = await storageService.getFile(userId, fileName);
+      if (result) {
+        pptData = result.content;
+      }
+    }
+
+    // 如果GitHub失败，尝试内存存储fallback
+    if (!pptData && storageService === githubService) {
+      try {
+        const memoryResult = await memoryStorageService.getFile(userId, fileName);
+        if (memoryResult) {
+          pptData = memoryResult.content;
+        }
+      } catch (memoryError) {
+        // 忽略内存存储错误
+      }
+    }
+
+    if (!pptData) {
+      return res.status(404).json({ error: 'PPT not found' });
+    }
+
+    if (slideIdx >= pptData.slides.length || slideIdx < 0) {
+      return res.status(404).json({ error: 'Slide not found' });
+    }
+
+    // 生成HTML内容（复用现有函数）
+    const htmlContent = generateSlideHTML(pptData, slideIdx, pptData.title);
+    
+    // 生成截图
+    const screenshot = await screenshotService.generateScreenshot(htmlContent);
+    
+    // 返回图片
+    res.setHeader('Content-Type', 'image/jpeg');
+    res.setHeader('Cache-Control', 'public, max-age=300'); // 5分钟缓存
+    res.setHeader('Content-Disposition', `inline; filename="${pptData.title}-${slideIdx + 1}.jpg"`);
+    res.send(screenshot);
+  } catch (error) {
+    console.error('Screenshot generation error:', error);
+    next(error);
+  }
+});
+
 export default router;