feat: 添加磁盘空间检查功能，处理因空间不足而暂存的下载任务

sql/add-disk-space-check.sql

@@ -0,0 +1,2 @@
+-- 添加磁盘空间暂存字段到订阅下载表
+ALTER TABLE "AppRssSubscriptionDownloads" ADD COLUMN "IsPendingDueToLowDiskSpace" INTEGER NOT NULL DEFAULT 0;

src/DFApp.Application.Contracts/Rss/RssSubscriptionDto.cs

@@ -111,6 +111,8 @@ public class RssSubscriptionDownloadDto : EntityDto<long>
 
         public string? DownloadStatusText { get; set; }
 
+        public bool IsPendingDueToLowDiskSpace { get; set; }
+
         public string? ErrorMessage { get; set; }
 
         public DateTime? DownloadStartTime { get; set; }

src/DFApp.Application/Background/DiskSpaceCheckWorker.cs

@@ -0,0 +1,54 @@
+using DFApp.Rss;
+using System;
+using System.IO;
+using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
+using Quartz;
+using Volo.Abp.BackgroundWorkers.Quartz;
+using Volo.Abp.DependencyInjection;
+
+namespace DFApp.Background
+{
+    /// <summary>
+    /// 磁盘空间检查后台任务，处理因空间不足而暂存的下载
+    /// </summary>
+    public class DiskSpaceCheckWorker : QuartzBackgroundWorkerBase, ITransientDependency
+    {
+        private readonly IRssSubscriptionService _rssSubscriptionService;
+
+        public DiskSpaceCheckWorker(
+            IRssSubscriptionService rssSubscriptionService)
+        {
+            _rssSubscriptionService = rssSubscriptionService;
+
+            JobDetail = JobBuilder
+                .Create<DiskSpaceCheckWorker>()
+                .WithIdentity(nameof(DiskSpaceCheckWorker))
+                .Build();
+
+            Trigger = TriggerBuilder
+                .Create()
+                .WithIdentity(nameof(DiskSpaceCheckWorker))
+                .WithSimpleSchedule(x => x
+                    .WithIntervalInMinutes(10)
+                    .RepeatForever())
+                .Build();
+        }
+
+        public override async Task Execute(IJobExecutionContext context)
+        {
+            Logger.LogInformation("开始执行磁盘空间检查任务");
+
+            try
+            {
+                await _rssSubscriptionService.ProcessPendingDownloadsAsync();
+
+                Logger.LogInformation("磁盘空间检查任务完成");
+            }
+            catch (Exception ex)
+            {
+                Logger.LogError(ex, "磁盘空间检查任务执行失败");
+            }
+        }
+    }
+}

src/DFApp.Application/Rss/RssSubscriptionService.cs

@@ -2,6 +2,7 @@
 using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
 using System.Threading.Tasks;
 using Volo.Abp.DependencyInjection;
@@ -163,6 +164,9 @@ public async Task<List<RssSubscriptionMatchResult>> MatchSubscriptionsAsync(RssM
             return results;
         }
 
+        private const long MinDiskSpaceGB = 2;
+        private const long MinDiskSpaceBytes = MinDiskSpaceGB * 1024 * 1024 * 1024;
+
         public async Task CreateDownloadTaskAsync(long subscriptionId, long rssMirrorItemId)
         {
             var subscription = await _rssSubscriptionRepository.GetAsync(subscriptionId);
@@ -178,6 +182,27 @@ public async Task CreateDownloadTaskAsync(long subscriptionId, long rssMirrorIte
                 return;
             }
 
+            var availableSpace = GetAvailableDiskSpace();
+
+            if (availableSpace < MinDiskSpaceBytes)
+            {
+                _logger.LogWarning("磁盘空间不足 {MinGB} GB，暂存订阅 {SubscriptionName} 的下载: {Title}", 
+                    MinDiskSpaceGB, subscription.Name, item.Title);
+
+                var pendingRecord = new RssSubscriptionDownload
+                {
+                    SubscriptionId = subscriptionId,
+                    RssMirrorItemId = rssMirrorItemId,
+                    Aria2Gid = string.Empty,
+                    DownloadStatus = 0,
+                    IsPendingDueToLowDiskSpace = true,
+                    CreationTime = DateTime.Now
+                };
+
+                await _rssSubscriptionDownloadRepository.InsertAsync(pendingRecord);
+                return;
+            }
+
             var downloadRequest = new AddDownloadRequestDto
             {
                 Urls = new List<string> { item.Link },
@@ -203,5 +228,75 @@ public async Task CreateDownloadTaskAsync(long subscriptionId, long rssMirrorIte
             _logger.LogInformation("订阅 {SubscriptionName} 自动下载: {Title} (GID: {Gid})", 
                 subscription.Name, item.Title, result.Id);
         }
+
+        private long GetAvailableDiskSpace()
+        {
+            try
+            {
+                var currentDirectory = Directory.GetCurrentDirectory();
+                var driveInfo = new DriveInfo(Path.GetPathRoot(currentDirectory)!);
+                return driveInfo.AvailableFreeSpace;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "获取磁盘空间失败");
+                return 0;
+            }
+        }
+
+        public async Task ProcessPendingDownloadsAsync()
+        {
+            var availableSpace = GetAvailableDiskSpace();
+
+            if (availableSpace < MinDiskSpaceBytes)
+            {
+                _logger.LogInformation("磁盘空间不足 {MinGB} GB，跳过暂存下载处理", MinDiskSpaceGB);
+                return;
+            }
+
+            var pendingDownloads = await _rssSubscriptionDownloadRepository.GetListAsync(
+                d => d.IsPendingDueToLowDiskSpace && d.DownloadStatus == 0);
+
+            if (!pendingDownloads.Any())
+            {
+                return;
+            }
+
+            _logger.LogInformation("找到 {Count} 个暂存的下载任务", pendingDownloads.Count);
+
+            foreach (var download in pendingDownloads)
+            {
+                try
+                {
+                    var subscription = await _rssSubscriptionRepository.GetAsync(download.SubscriptionId);
+                    var item = await _rssMirrorItemRepository.GetAsync(download.RssMirrorItemId);
+
+                    var downloadRequest = new AddDownloadRequestDto
+                    {
+                        Urls = new List<string> { item.Link },
+                        VideoOnly = subscription.VideoOnly,
+                        EnableKeywordFilter = subscription.EnableKeywordFilter,
+                        SavePath = subscription.SavePath
+                    };
+
+                    var result = await _aria2Service.AddDownloadAsync(downloadRequest);
+
+                    download.Aria2Gid = result.Id;
+                    download.DownloadStatus = 1;
+                    download.DownloadStartTime = DateTime.Now;
+                    download.IsPendingDueToLowDiskSpace = false;
+
+                    await _rssSubscriptionDownloadRepository.UpdateAsync(download);
+
+                    _logger.LogInformation("已处理暂存下载: {Id} (GID: {Gid})", download.Id, result.Id);
+                }
+                catch (Exception ex)
+                {
+                    _logger.LogError(ex, "处理暂存下载失败: {Id}", download.Id);
+                }
+            }
+
+            _logger.LogInformation("已处理 {Count} 个暂存下载任务", pendingDownloads.Count);
+        }
     }
 }

src/DFApp.Domain/Rss/IRssSubscriptionService.cs

@@ -8,6 +8,7 @@ public interface IRssSubscriptionService
     {
         Task<List<RssSubscriptionMatchResult>> MatchSubscriptionsAsync(RssMirrorItem item);
         Task CreateDownloadTaskAsync(long subscriptionId, long rssMirrorItemId);
+        Task ProcessPendingDownloadsAsync();
     }
 
     public class RssSubscriptionMatchResult

src/DFApp.Domain/Rss/RssSubscriptionDownload.cs

@@ -22,6 +22,8 @@ public class RssSubscriptionDownload : Entity<long>, IHasCreationTime
 
         public DateTime? DownloadCompleteTime { get; set; }
 
+        public bool IsPendingDueToLowDiskSpace { get; set; }
+
         public DateTime CreationTime { get; set; }
 
         public Guid? CreatorId { get; set; }