fix: handle broken thumbnails and incomplete uploads

- Implement automatic thumbnail regeneration for corrupted files
- Add validation middleware to check uploaded files before processing
- Improve error handling for "Premature end of input file" errors
- Delete and regenerate thumbnails when serving fails
- Add file integrity checks during upload process
- Better error reporting for failed uploads

This fixes the VipsJpeg errors and ensures reliable thumbnail generation.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

backend/src/middleware/uploadValidation.js

@@ -0,0 +1,90 @@
+const fs = require('fs').promises;
+const path = require('path');
+const sharp = require('sharp');
+const logger = require('../utils/logger');
+
+/**
+ * Validate uploaded file is complete and not corrupted
+ */
+async function validateUploadedFile(filePath) {
+  try {
+    // Check file exists and has size
+    const stats = await fs.stat(filePath);
+    if (stats.size === 0) {
+      throw new Error('File is empty');
+    }
+    
+    // For image files, verify they can be read by Sharp
+    const ext = path.extname(filePath).toLowerCase();
+    const imageExtensions = ['.jpg', '.jpeg', '.png', '.gif', '.webp'];
+    
+    if (imageExtensions.includes(ext)) {
+      // Try to read metadata - this will fail if image is corrupted
+      const metadata = await sharp(filePath).metadata();
+      
+      if (!metadata.width || !metadata.height) {
+        throw new Error('Invalid image dimensions');
+      }
+      
+      // Check for reasonable dimensions
+      if (metadata.width < 10 || metadata.height < 10) {
+        throw new Error('Image dimensions too small');
+      }
+      
+      return true;
+    }
+    
+    return true;
+  } catch (error) {
+    logger.error(`File validation failed for ${filePath}:`, error.message);
+    throw error;
+  }
+}
+
+/**
+ * Middleware to validate uploaded files after multer processing
+ */
+async function validateUploadedFiles(req, res, next) {
+  if (!req.files || req.files.length === 0) {
+    return next();
+  }
+  
+  const validFiles = [];
+  const invalidFiles = [];
+  
+  // Validate each file
+  for (const file of req.files) {
+    try {
+      await validateUploadedFile(file.path);
+      validFiles.push(file);
+    } catch (error) {
+      logger.warn(`Removing invalid upload ${file.originalname}: ${error.message}`);
+      invalidFiles.push({
+        filename: file.originalname,
+        error: error.message
+      });
+      
+      // Delete the invalid file
+      try {
+        await fs.unlink(file.path);
+      } catch (unlinkErr) {
+        logger.error(`Failed to delete invalid file ${file.path}:`, unlinkErr.message);
+      }
+    }
+  }
+  
+  // Update req.files to only include valid files
+  req.files = validFiles;
+  
+  // Store invalid files info for response
+  if (invalidFiles.length > 0) {
+    req.invalidFiles = invalidFiles;
+  }
+  
+  next();
+}
+
+module.exports = {
+  validateUploadedFile,
+  validateUploadedFiles
+};

backend/src/routes/adminPhotos.js

@@ -4,9 +4,10 @@ const path = require('path');
 const fs = require('fs').promises;
 const { db, logActivity } = require('../database/db');
 const { adminAuth } = require('../middleware/auth');
-const { generateThumbnail } = require('../services/imageProcessor');
+const { generateThumbnail, ensureThumbnail } = require('../services/imageProcessor');
 const { generatePhotoFilename } = require('../utils/filenameSanitizer');
 const { escapeLikePattern } = require('../utils/sqlSecurity');
+const { validateUploadedFiles } = require('../middleware/uploadValidation');
 const router = express.Router();
 
 // Get storage path from environment or default
@@ -106,7 +107,7 @@ router.post('/:eventId/upload', adminAuth, (req, res, next) => {
     }
     next();
   });
-}, validateUploadContent, async (req, res) => {
+}, validateUploadContent, validateUploadedFiles, async (req, res) => {
   try {
     const { eventId } = req.params;
     const { category_id } = req.body;
@@ -197,8 +198,14 @@ router.post('/:eventId/upload', adminAuth, (req, res, next) => {
             file.filename = newFilename;
             file.path = newPath;
             
-            // Generate thumbnail with new filename
-            const thumbnailPath = await generateThumbnail(file.path);
+            // Generate thumbnail with new filename (with better error handling)
+            let thumbnailPath = null;
+            try {
+              thumbnailPath = await generateThumbnail(file.path);
+            } catch (thumbError) {
+              console.error(`Thumbnail generation failed for ${file.filename}:`, thumbError.message);
+              // Continue without thumbnail rather than failing the whole upload
+            }
             
             // Calculate relative paths
             const storagePath = getStoragePath();
@@ -269,19 +276,23 @@ router.post('/:eventId/upload', adminAuth, (req, res, next) => {
       { type: 'admin', id: req.admin.id, name: req.admin.username }
     );
     
+    // Include any files that were invalid from the validation middleware
+    const totalInvalidFiles = (req.invalidFiles || []).concat(errors);
+    
     // Prepare response
+    const totalAttempted = req.files.length + (req.invalidFiles ? req.invalidFiles.length : 0);
     const response = {
       message: `Successfully uploaded ${uploadedPhotos.length} photos`,
       photos: uploadedPhotos,
-      totalFiles: req.files.length,
+      totalFiles: totalAttempted,
       successCount: uploadedPhotos.length,
-      failureCount: errors.length
+      failureCount: totalInvalidFiles.length
     };
     
     // Include error details if any files failed
-    if (errors.length > 0) {
-      response.errors = errors;
-      response.message = `Uploaded ${uploadedPhotos.length} of ${req.files.length} photos. ${errors.length} failed.`;
+    if (totalInvalidFiles.length > 0) {
+      response.errors = totalInvalidFiles;
+      response.message = `Uploaded ${uploadedPhotos.length} of ${totalAttempted} photos. ${totalInvalidFiles.length} failed.`;
     }
     
     res.json(response);
@@ -613,26 +624,24 @@ router.get('/:eventId/thumbnail/:photoId', adminAuth, async (req, res) => {
       .where({ id: photoId, event_id: eventId })
       .first();
     
-    if (!photo || !photo.thumbnail_path) {
-      console.error(`Thumbnail not found for photo ${photoId}, event ${eventId}`);
-      return res.status(404).json({ error: 'Thumbnail not found' });
+    if (!photo) {
+      console.error(`Photo not found: ${photoId}, event ${eventId}`);
+      return res.status(404).json({ error: 'Photo not found' });
+    }
+    
+    // Ensure thumbnail exists and is valid, regenerate if needed
+    const thumbnailPath = await ensureThumbnail(photo);
+    
+    if (!thumbnailPath) {
+      console.error(`Failed to generate thumbnail for photo ${photoId}`);
+      return res.status(404).json({ error: 'Thumbnail generation failed' });
     }
     
     const storagePath = getStoragePath();
-    const filePath = path.join(storagePath, photo.thumbnail_path);
-    
-    console.log(`Attempting to serve thumbnail: ${filePath}`);
-    
-    // Check if file exists
-    try {
-      await fs.access(filePath);
-    } catch (error) {
-      console.error(`Thumbnail file not found: ${filePath}`, error);
-      return res.status(404).json({ error: 'Thumbnail file not found' });
-    }
+    const filePath = path.join(storagePath, thumbnailPath);
     
     // Set appropriate headers
-    res.setHeader('Content-Type', `image/${path.extname(photo.thumbnail_path).slice(1)}`);
+    res.setHeader('Content-Type', 'image/jpeg'); // Thumbnails are always JPEG
     res.setHeader('Cache-Control', 'private, max-age=3600');
     res.setHeader('Cross-Origin-Resource-Policy', 'cross-origin');
     

backend/src/services/imageProcessor.js

@@ -1,6 +1,7 @@
 const sharp = require('sharp');
 const path = require('path');
 const fs = require('fs').promises;
+const logger = require('../utils/logger');
 
 // Configure sharp for better memory management with large batches
 sharp.cache(false); // Disable cache to prevent memory buildup
@@ -10,7 +11,7 @@ const THUMBNAIL_WIDTH = 300;
 const getStoragePath = () => process.env.STORAGE_PATH || path.join(__dirname, '../../../storage');
 const getThumbnailPath = () => path.join(getStoragePath(), 'thumbnails');
 
-async function generateThumbnail(imagePath) {
+async function generateThumbnail(imagePath, options = {}) {
   const filename = path.basename(imagePath);
   const thumbnailFilename = `thumb_${filename}`;
   const thumbnailDir = getThumbnailPath();
@@ -19,11 +20,29 @@ async function generateThumbnail(imagePath) {
   // Ensure thumbnail directory exists
   await fs.mkdir(thumbnailDir, { recursive: true });
   
+  // Check if we need to regenerate (for broken thumbnails)
+  if (options.regenerate) {
+    try {
+      await fs.unlink(thumbnailPath);
+      logger.info(`Deleted broken thumbnail: ${thumbnailPath}`);
+    } catch (err) {
+      // File might not exist, that's okay
+    }
+  }
+  
   try {
-    // Generate thumbnail with memory-efficient settings
+    // First, verify the source image is complete and valid
+    const metadata = await sharp(imagePath).metadata();
+    
+    if (!metadata.width || !metadata.height) {
+      throw new Error('Invalid image metadata - file may be incomplete');
+    }
+    
+    // Generate thumbnail with memory-efficient settings and error handling
     await sharp(imagePath, { 
       limitInputPixels: 268402689, // ~16k x 16k max
-      sequentialRead: true // More memory efficient for large images
+      sequentialRead: true, // More memory efficient for large images
+      failOnError: false // Don't fail on minor issues
     })
       .resize(THUMBNAIL_WIDTH, null, {
         withoutEnlargement: true,
@@ -36,12 +55,80 @@ async function generateThumbnail(imagePath) {
       })
       .toFile(thumbnailPath);
     
+    // Verify the thumbnail was created successfully
+    const stats = await fs.stat(thumbnailPath);
+    if (stats.size === 0) {
+      throw new Error('Generated thumbnail is empty');
+    }
+    
     return path.relative(getStoragePath(), thumbnailPath);
   } catch (error) {
-    console.error(`Failed to generate thumbnail for ${filename}:`, error);
+    logger.error(`Failed to generate thumbnail for ${filename}:`, error.message);
+    
+    // Clean up any partially created file
+    try {
+      await fs.unlink(thumbnailPath);
+    } catch (unlinkErr) {
+      // Ignore unlink errors
+    }
+    
     // Return null if thumbnail generation fails, don't fail the whole upload
     return null;
   }
 }
 
-module.exports = { generateThumbnail };
+/**
+ * Check if a thumbnail exists and is valid
+ */
+async function isThumbnailValid(thumbnailPath) {
+  try {
+    const fullPath = path.join(getStoragePath(), thumbnailPath);
+    const stats = await fs.stat(fullPath);
+    
+    // Check if file exists and has content
+    if (stats.size === 0) {
+      return false;
+    }
+    
+    // Try to read metadata to ensure it's a valid image
+    await sharp(fullPath).metadata();
+    return true;
+  } catch (error) {
+    return false;
+  }
+}
+
+/**
+ * Regenerate thumbnail if it's broken or missing
+ */
+async function ensureThumbnail(photo) {
+  const storagePath = getStoragePath();
+  const originalPath = path.join(storagePath, 'events/active', photo.path);
+  
+  // Check if thumbnail exists and is valid
+  if (photo.thumbnail_path) {
+    const isValid = await isThumbnailValid(photo.thumbnail_path);
+    if (isValid) {
+      return photo.thumbnail_path;
+    }
+    logger.warn(`Invalid thumbnail detected for photo ${photo.id}, regenerating...`);
+  }
+  
+  // Generate new thumbnail
+  const newThumbnailPath = await generateThumbnail(originalPath, { regenerate: true });
+  
+  if (newThumbnailPath) {
+    // Update database with new thumbnail path
+    const { db } = require('../database/db');
+    await db('photos')
+      .where({ id: photo.id })
+      .update({ thumbnail_path: newThumbnailPath });
+    
+    logger.info(`Regenerated thumbnail for photo ${photo.id}`);
+    return newThumbnailPath;
+  }
+  
+  return null;
+}
+
+module.exports = { generateThumbnail, isThumbnailValid, ensureThumbnail };