feat(pictureManagement): improve thumbnail generation and handling for uploaded images

Services/Background/BackgroundTaskQueue.cs

@@ -236,38 +236,58 @@ public sealed class BackgroundTaskQueue : IBackgroundTaskQueue, IDisposable
                 throw new Exception($"找不到图片文件: {localFilePath}");
             }
 
-            // 创建缩略图
+            // 检查并生成缩略图（如果不存在）
             await UpdatePictureStatus(task.PictureId, ProcessingStatus.Processing, 20);
-            var thumbnailPath = Path.Combine(
-                Path.GetDirectoryName(localFilePath)!,
-                Path.GetFileNameWithoutExtension(Path.GetFileName(localFilePath)) + "_thumb.webp");
-
-            await ImageHelper.CreateThumbnailAsync(localFilePath, thumbnailPath, 500);
-
-            // 更新缩略图路径到数据库
-            await UpdatePictureStatus(task.PictureId, ProcessingStatus.Processing, 25);
-
-            if (picture.StorageType == StorageType.Local)
+            
+            string thumbnailForAI = localFilePath; // 用于AI分析的缩略图路径
+            
+            if (string.IsNullOrEmpty(picture.ThumbnailPath))
             {
-                // 本地存储缩略图
-                var relativeThumbnailPath =
-                    $"/Uploads/{Path.GetRelativePath("Uploads", Path.GetDirectoryName(thumbnailPath)!)}/{Path.GetFileName(thumbnailPath)}";
-                picture.ThumbnailPath = relativeThumbnailPath.Replace('\\', '/');
+                // 如果缩略图不存在，生成缩略图
+                var thumbnailPath = Path.Combine(
+                    Path.GetDirectoryName(localFilePath)!,
+                    Path.GetFileNameWithoutExtension(Path.GetFileName(localFilePath)) + "_thumb.webp");
+
+                await ImageHelper.CreateThumbnailAsync(localFilePath, thumbnailPath, 500);
+                thumbnailForAI = thumbnailPath;
+
+                // 更新缩略图路径到数据库
+                await UpdatePictureStatus(task.PictureId, ProcessingStatus.Processing, 25);
+
+                if (picture.StorageType == StorageType.Local)
+                {
+                    // 本地存储缩略图
+                    var relativeThumbnailPath =
+                        $"/Uploads/{Path.GetRelativePath("Uploads", Path.GetDirectoryName(thumbnailPath)!)}/{Path.GetFileName(thumbnailPath)}";
+                    picture.ThumbnailPath = relativeThumbnailPath.Replace('\\', '/');
+                }
+                else
+                {
+                    // 上传缩略图并获取存储路径或元数据
+                    await using var thumbnailFileStream = new FileStream(thumbnailPath, FileMode.Open, FileAccess.Read);
+                    var thumbnailFileName = Path.GetFileName(thumbnailPath);
+                    var thumbnailContentType = "image/webp";
+
+                    string thumbnailStoragePath = await storageService.ExecuteAsync(
+                        picture.StorageType,
+                        provider => provider.SaveAsync(thumbnailFileStream, thumbnailFileName, thumbnailContentType));
+
+                    // 将路径或元数据存储到ThumbnailPath
+                    picture.ThumbnailPath = thumbnailStoragePath;
+                }
             }
             else
             {
-                // 非本地存储，上传缩略图到对应的存储服务
-                await using var thumbnailFileStream = new FileStream(thumbnailPath, FileMode.Open, FileAccess.Read);
-                var thumbnailFileName = Path.GetFileName(thumbnailPath);
-                var thumbnailContentType = "image/webp";
-
-                // 上传缩略图并获取存储路径或元数据
-                string thumbnailStoragePath = await storageService.ExecuteAsync(
-                    picture.StorageType,
-                    provider => provider.SaveAsync(thumbnailFileStream, thumbnailFileName, thumbnailContentType));
-
-                // 将路径或元数据存储到ThumbnailPath
-                picture.ThumbnailPath = thumbnailStoragePath;
+                // 如果缩略图已存在，下载用于AI分析
+                if (picture.StorageType != StorageType.Local)
+                {
+                    thumbnailForAI = await storageService.ExecuteAsync(picture.StorageType,
+                        provider => provider.DownloadFileAsync(picture.ThumbnailPath));
+                }
+                else
+                {
+                    thumbnailForAI = Path.Combine(Directory.GetCurrentDirectory(), picture.ThumbnailPath.TrimStart('/'));
+                }
             }
 
             // 3. 提取EXIF信息
@@ -283,7 +303,7 @@ public sealed class BackgroundTaskQueue : IBackgroundTaskQueue, IDisposable
 
             // 5. 将缩略图转换为Base64并调用AI分析
             await UpdatePictureStatus(task.PictureId, ProcessingStatus.Processing, 50);
-            string base64Image = await ImageHelper.ConvertImageToBase64(thumbnailPath);
+            string base64Image = await ImageHelper.ConvertImageToBase64(thumbnailForAI);
             var (title, description) = await aiService.AnalyzeImageAsync(base64Image);
 
             // 6. 确定最终标题和描述

Services/Media/PictureService.cs

@@ -516,12 +516,67 @@ public class PictureService(
             }
         }
 
+        string? tempOriginalFileForThumbnail = null;
+        string? tempThumbnailFile = null;
+
         try
         {
+            // 如果是匿名用户或者需要立即生成缩略图，先保存到临时文件
+            bool shouldGenerateThumbnail = userId.HasValue; // 只为注册用户生成缩略图
+            
+            if (shouldGenerateThumbnail)
+            {
+                tempOriginalFileForThumbnail = Path.GetTempFileName();
+                
+                // 保存原始文件到临时位置用于生成缩略图
+                await using (var tempFileStream = new FileStream(tempOriginalFileForThumbnail, FileMode.Create))
+                {
+                    if (finalStream != fileStream) // 已经是转换后的流
+                    {
+                        finalStream.Position = 0;
+                        await finalStream.CopyToAsync(tempFileStream);
+                        finalStream.Position = 0; // 重置位置用于后续上传
+                    }
+                    else
+                    {
+                        await finalStream.CopyToAsync(tempFileStream);
+                        finalStream.Position = 0; // 重置位置用于后续上传
+                    }
+                }
+            }
+
             // 使用存储服务保存文件
             string relativePath = await storageService.ExecuteAsync(storageType.Value,
                 provider => provider.SaveAsync(finalStream, finalFileName, finalContentType));
 
+            string? thumbnailPath = null;
+
+            // 生成缩略图
+            if (shouldGenerateThumbnail && !string.IsNullOrEmpty(tempOriginalFileForThumbnail))
+            {
+                try
+                {
+                    tempThumbnailFile = Path.GetTempFileName();
+                    string thumbnailFileName = Path.ChangeExtension(tempThumbnailFile, ".webp");
+                    File.Move(tempThumbnailFile, thumbnailFileName);
+                    tempThumbnailFile = thumbnailFileName;
+
+                    // 生成缩略图
+                    await ImageHelper.CreateThumbnailAsync(tempOriginalFileForThumbnail, tempThumbnailFile, 500);
+
+                    // 上传缩略图
+                    await using var thumbnailFileStream = new FileStream(tempThumbnailFile, FileMode.Open, FileAccess.Read);
+                    var thumbnailStorageFileName = Path.GetFileNameWithoutExtension(finalFileName) + "_thumb.webp";
+                    
+                    thumbnailPath = await storageService.ExecuteAsync(storageType.Value,
+                        provider => provider.SaveAsync(thumbnailFileStream, thumbnailStorageFileName, "image/webp"));
+                }
+                catch (Exception ex)
+                {
+                    Console.WriteLine($"生成缩略图失败: {ex.Message}");
+                }
+            }
+
             // 创建基本的Picture对象，使用文件名作为标题和描述
             string initialTitle = Path.GetFileNameWithoutExtension(originalFileName);
             string initialDescription = $"Uploaded on {DateTime.UtcNow}";
@@ -570,7 +625,7 @@ public class PictureService(
                 AlbumId = albumId,
                 StorageType = storageType.Value,
                 ProcessingStatus = isAnonymous ? ProcessingStatus.Completed : ProcessingStatus.Pending,
-                ThumbnailPath = isAnonymous ? relativePath : null
+                ThumbnailPath = thumbnailPath ?? (isAnonymous ? relativePath : null) // 匿名用户使用原图作为缩略图
             };
 
             dbContext.Pictures.Add(picture);
@@ -588,10 +643,13 @@ public class PictureService(
                 Name = picture.Name,
                 Path = await storageService.ExecuteAsync(picture.StorageType, provider =>
                     Task.FromResult(provider.GetUrl(relativePath))),
-                ThumbnailPath = isAnonymous
+                ThumbnailPath = !string.IsNullOrEmpty(thumbnailPath)
                     ? await storageService.ExecuteAsync(picture.StorageType, provider =>
-                        Task.FromResult(provider.GetUrl(relativePath)))
-                    : null,
+                        Task.FromResult(provider.GetUrl(thumbnailPath)))
+                    : (isAnonymous 
+                        ? await storageService.ExecuteAsync(picture.StorageType, provider =>
+                            Task.FromResult(provider.GetUrl(relativePath)))
+                        : null),
                 Description = picture.Description,
                 CreatedAt = picture.CreatedAt,
                 Tags = new List<string>(),
@@ -605,6 +663,17 @@ public class PictureService(
         }
         finally
         {
+            // 清理临时文件
+            if (!string.IsNullOrEmpty(tempOriginalFileForThumbnail) && File.Exists(tempOriginalFileForThumbnail))
+            {
+                try { File.Delete(tempOriginalFileForThumbnail); } catch { }
+            }
+            
+            if (!string.IsNullOrEmpty(tempThumbnailFile) && File.Exists(tempThumbnailFile))
+            {
+                try { File.Delete(tempThumbnailFile); } catch { }
+            }
+
             // 清理转换后的临时流
             if (finalStream != fileStream && finalStream is FileStream tempFileStream)
             {
@@ -613,8 +682,8 @@ public class PictureService(
                 if (File.Exists(tempFilePath)) File.Delete(tempFilePath);
 
                 // 同时清理原始临时文件
-                string tempOriginalFile = Path.ChangeExtension(tempFilePath, null);
-                if (File.Exists(tempOriginalFile)) File.Delete(tempOriginalFile);
+                string tempOriginalFileFromConvert = Path.ChangeExtension(tempFilePath, null);
+                if (File.Exists(tempOriginalFileFromConvert)) File.Delete(tempOriginalFileFromConvert);
             }
         }
     }