feat: 新增可配置的文件库扫描日志记录及缩略图清理功能

- 为文件库的定时轮询及根目录扫描过程，新增扫描生​​命周期日志
- 允许通过 `appsettings` 配置文件，自定义定时扫描的轮询间隔
- 当检测到媒体文件已被删除时，自动清理过期的缩略图映射记录及对应的缩略图文件

FileShare-API/Configuration/ServicesConfiguration.cs

@@ -52,6 +52,7 @@ namespace FileShare_API.Configuration
             services.AddScoped<IFileLibraryEndpointService, FileLibraryEndpointService>();
             services.AddScoped<IFileStreamService, FileStreamService>();
             services.AddScoped<IQrCodeService, QrCodeService>();
+            services.Configure<FileLibraryScanOptions>(configuration.GetSection(nameof(FileLibraryScanOptions)));
             services.AddHostedService<FileLibraryScanHostedService>();
             services.AddDataProtection()
                 .PersistKeysToFileSystem(new DirectoryInfo(Path.Combine(AppContext.BaseDirectory, "data-protection-keys")));

FileShare-API/FileShare-API.csproj.user

@@ -2,6 +2,7 @@
 <Project ToolsVersion="Current" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <ActiveDebugProfile>http</ActiveDebugProfile>
+    <NameOfLastUsedPublishProfile>D:\Project\FileShare\FileShare-API\Properties\PublishProfiles\FolderProfile.pubxml</NameOfLastUsedPublishProfile>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
     <DebuggerFlavor>ProjectDebugger</DebuggerFlavor>

FileShare-API/Services/FileLibraryScanHostedService.cs

@@ -1,27 +1,30 @@
 using FileShare_Services.Services.FileLibrary;
+using Microsoft.Extensions.Options;
 
 namespace FileShare_API.Services
 {
     /// <summary>
-    /// 文件库定时扫描后台服务，每分钟执行一次扫描，检查是否有需要扫描的文件库目录。
+    /// 文件库定时扫描后台服务，按配置间隔检查是否有需要扫描的文件库目录。
     /// </summary>
-    public sealed class FileLibraryScanHostedService(IServiceScopeFactory scopeFactory, ILogger<FileLibraryScanHostedService> logger)
+    public sealed class FileLibraryScanHostedService(
+        IServiceScopeFactory scopeFactory,
+        IOptions<FileLibraryScanOptions> options,
+        ILogger<FileLibraryScanHostedService> logger)
         : BackgroundService
     {
-        /// <summary>
-        /// 扫描间隔，固定为 1 分钟。
-        /// </summary>
-        private static readonly TimeSpan Interval = TimeSpan.FromMinutes(1);
+        /// <summary>后台服务检查到期扫描任务的轮询间隔。</summary>
+        private readonly TimeSpan _interval = TimeSpan.FromMinutes(Math.Max(1, options.Value.PollingIntervalMinutes));
 
         /// <summary>
-        /// 启动扫描循环，首次立即执行，之后按 <see cref="Interval"/> 周期重复执行。
+        /// 启动扫描循环，首次立即执行，之后按配置的轮询间隔重复执行。
         /// </summary>
         /// <param name="stoppingToken">应用关闭时触发的取消令牌。</param>
         protected override async Task ExecuteAsync(CancellationToken stoppingToken)
         {
+            logger.LogInformation("文件库定时扫描服务已启动，轮询间隔 {IntervalMinutes} 分钟。", _interval.TotalMinutes);
             await ScanAsync(stoppingToken);
 
-            using var timer = new PeriodicTimer(Interval);
+            using var timer = new PeriodicTimer(_interval);
             while (await timer.WaitForNextTickAsync(stoppingToken))
             {
                 await ScanAsync(stoppingToken);
@@ -34,14 +37,21 @@ namespace FileShare_API.Services
         /// <param name="cancellationToken">取消令牌。</param>
         private async Task ScanAsync(CancellationToken cancellationToken)
         {
+            var startedAt = DateTime.UtcNow;
+            logger.LogInformation("文件库定时扫描轮询开始。");
+
             try
             {
                 await using var scope = scopeFactory.CreateAsyncScope();
                 var scanner = scope.ServiceProvider.GetRequiredService<IFileLibraryService>();
                 await scanner.ScanDueRootsAsync(cancellationToken);
+                logger.LogInformation(
+                    "文件库定时扫描轮询完成，耗时 {ElapsedMilliseconds} ms。",
+                    (DateTime.UtcNow - startedAt).TotalMilliseconds);
             }
             catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
             {
+                logger.LogInformation("文件库定时扫描轮询已取消。");
             }
             catch (Exception ex)
             {

FileShare-API/Services/FileLibraryScanOptions.cs

@@ -0,0 +1,13 @@
+namespace FileShare_API.Services
+{
+    /// <summary>
+    /// 文件库定时扫描后台服务配置。
+    /// </summary>
+    public sealed class FileLibraryScanOptions
+    {
+        /// <summary>
+        /// 后台服务检查到期文件库目录的轮询间隔分钟数。
+        /// </summary>
+        public int PollingIntervalMinutes { get; set; } = 1;
+    }
+}

FileShare-API/appsettings.json

@@ -29,5 +29,8 @@
     "RootPath": "thumbnails",
     "FfmpegPath": "tools/ffmpeg/bin/ffmpeg.exe",
     "FfprobePath": "tools/ffmpeg/bin/ffprobe.exe"
+  },
+  "FileLibraryScanOptions": {
+    "PollingIntervalMinutes": 5
   }
 }