Handle nzb files containing zero segments.

Author: nzbdav-dev

backend/Clients/CachingNntpClient.cs

@@ -21,6 +21,7 @@ public override async Task<YencHeader> GetSegmentYencHeaderAsync(string segmentI
 
     public override async Task<long> GetFileSizeAsync(NzbFile file, CancellationToken cancellationToken)
     {
+        if (file.Segments.Count == 0) return 0;
         var header = await GetSegmentYencHeaderAsync(file.Segments[0].MessageId, cancellationToken);
         return header.FileSize;
     }

backend/Clients/ThreadSafeNntpClient.cs

@@ -76,6 +76,7 @@ public async Task<YencHeader> GetSegmentYencHeaderAsync(string segmentId, Cancel
 
     public async Task<long> GetFileSizeAsync(NzbFile file, CancellationToken cancellationToken)
     {
+        if (file.Segments.Count == 0) return 0;
         var header = await GetSegmentYencHeaderAsync(file.Segments[0].MessageId.Value, cancellationToken);
         return header.FileSize;
     }

backend/Extensions/NzbFileExtensions.cs

@@ -40,6 +40,7 @@ public static async Task<string> GetHeaderFileName
         CancellationToken ct = default
     )
     {
+        if (file.Segments.Count == 0) return "";
         var firstSegment = file.Segments[0].MessageId.Value;
         var header = await client.GetSegmentYencHeaderAsync(firstSegment, default);
         return header.FileName;

backend/Queue/FileProcessors/FileProcessor.cs

@@ -23,14 +23,11 @@ public static bool CanProcess(string filename)
     {
         try
         {
-            var firstSegment = nzbFile.Segments[0].MessageId.Value;
-            var header = await usenet.GetSegmentYencHeaderAsync(firstSegment, ct);
-
             return new Result()
             {
                 NzbFile = nzbFile,
                 FileName = filename,
-                FileSize = header.FileSize,
+                FileSize = await usenet.GetFileSizeAsync(nzbFile, ct),
             };
         }
 

backend/Queue/QueueItemProcessor.cs

@@ -85,15 +85,16 @@ private async Task ProcessQueueItemAsync(DateTime startTime)
         var documentBytes = Encoding.UTF8.GetBytes(queueItem.NzbContents);
         using var stream = new MemoryStream(documentBytes);
         var nzb = await NzbDocument.LoadAsync(stream);
+        var nzbFiles = nzb.Files.Where(x => x.Segments.Count > 0).ToList();
 
         // parse filenames for each nzb file
-        var filenamesTaskDictionary = nzb.Files.ToDictionary(x => x, x => x.GetFileName(usenetClient));
+        var filenamesTaskDictionary = nzbFiles.ToDictionary(x => x, x => x.GetFileName(usenetClient));
         var filenamesDictionary = new Dictionary<NzbFile, string>();
         foreach (var filenameTask in filenamesTaskDictionary)
             filenamesDictionary[filenameTask.Key] = await filenameTask.Value;
 
         // start file processing tasks
-        var fileProcessingTasks = nzb.Files
+        var fileProcessingTasks = nzbFiles
             .DistinctBy(x => filenamesDictionary[x])
             .Select(x => GetFileProcessor(x, filenamesDictionary[x]))
             .Where(x => x is not null)