Read file length for symlinks, supersedes #5775 and #5824

Jellyfin.Server/Infrastructure/SymlinkFollowingPhysicalFileResultExecutor.cs

@@ -0,0 +1,123 @@
+using System;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using MediaBrowser.Model.IO;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Http.Extensions;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
+using Microsoft.Extensions.Logging;
+using Microsoft.Net.Http.Headers;
+
+namespace Jellyfin.Server.Infrastructure
+{
+    /// <inheritdoc />
+    public class SymlinkFollowingPhysicalFileResultExecutor : PhysicalFileResultExecutor
+    {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SymlinkFollowingPhysicalFileResultExecutor"/> class.
+        /// </summary>
+        /// <param name="loggerFactory"></param>
+        public SymlinkFollowingPhysicalFileResultExecutor(ILoggerFactory loggerFactory) : base(loggerFactory)
+        {
+        }
+
+        /// <inheritdoc />
+        protected override FileMetadata GetFileInfo(string path)
+        {
+            var fileInfo = new FileInfo(path);
+            var length = fileInfo.Length;
+            // This may or may not be fixed in .NET 6, but looks like it will not https://github.com/dotnet/aspnetcore/issues/34371
+            if ((fileInfo.Attributes & FileAttributes.ReparsePoint) == FileAttributes.ReparsePoint)
+            {
+                using Stream thisFileStream = AsyncFile.OpenRead(path);
+                length = thisFileStream.Length;
+            }
+
+            return new FileMetadata
+            {
+                Exists = fileInfo.Exists,
+                Length = length,
+                LastModified = fileInfo.LastWriteTimeUtc
+            };
+        }
+
+        /// <inheritdoc />
+        protected override Task WriteFileAsync(ActionContext context, PhysicalFileResult result, RangeItemHeaderValue range, long rangeLength)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            if (result == null)
+            {
+                throw new ArgumentNullException(nameof(result));
+            }
+
+            if (range != null && rangeLength == 0)
+            {
+                return Task.CompletedTask;
+            }
+
+            // It's a bit of wasted IO to perform this check again, but non-symlinks shouldn't use this code
+            if (!IsSymLink(result.FileName))
+            {
+                return base.WriteFileAsync(context, result, range, rangeLength);
+            }
+
+            var response = context.HttpContext.Response;
+
+            if (range != null)
+            {
+                return SendFileAsync(result.FileName,
+                    response,
+                    offset: range.From ?? 0L,
+                    count: rangeLength);
+            }
+
+            return SendFileAsync(result.FileName,
+                response,
+                offset: 0,
+                count: null);
+        }
+
+        private async Task SendFileAsync(string filePath, HttpResponse response, long offset, long? count)
+        {
+            var fileInfo = GetFileInfo(filePath);
+            if (offset < 0 || offset > fileInfo.Length)
+            {
+                throw new ArgumentOutOfRangeException(nameof(offset), offset, string.Empty);
+            }
+
+            if (count.HasValue
+                && (count.Value < 0 || count.Value > fileInfo.Length - offset))
+            {
+                throw new ArgumentOutOfRangeException(nameof(count), count, string.Empty);
+            }
+
+            // Copied from SendFileFallback.SendFileAsync
+            const int bufferSize = 1024 * 16;
+
+            await using var fileStream = new FileStream(
+                filePath,
+                FileMode.Open,
+                FileAccess.Read,
+                FileShare.ReadWrite,
+                bufferSize: bufferSize,
+                options: (AsyncFile.UseAsyncIO ? FileOptions.Asynchronous : FileOptions.None) | FileOptions.SequentialScan);
+
+            fileStream.Seek(offset, SeekOrigin.Begin);
+            await StreamCopyOperation
+                .CopyToAsync(fileStream, response.Body, count, bufferSize, CancellationToken.None)
+                .ConfigureAwait(true);
+        }
+
+        private static bool IsSymLink(string path)
+        {
+            var fileInfo = new FileInfo(path);
+            return (fileInfo.Attributes & FileAttributes.ReparsePoint) == FileAttributes.ReparsePoint;
+        }
+    }
+}

Jellyfin.Server/Startup.cs

@@ -7,6 +7,7 @@ using System.Text;
 using Jellyfin.Networking.Configuration;
 using Jellyfin.Server.Extensions;
 using Jellyfin.Server.Implementations;
+using Jellyfin.Server.Infrastructure;
 using Jellyfin.Server.Middleware;
 using MediaBrowser.Common.Net;
 using MediaBrowser.Controller;
@@ -14,6 +15,8 @@ using MediaBrowser.Controller.Configuration;
 using MediaBrowser.Controller.Extensions;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Infrastructure;
 using Microsoft.AspNetCore.StaticFiles;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
@@ -56,6 +59,9 @@ namespace Jellyfin.Server
             {
                 options.HttpsPort = _serverApplicationHost.HttpsPort;
             });
+
+            // TODO remove once this is fixed upstream https://github.com/dotnet/aspnetcore/issues/34371
+            services.AddSingleton<IActionResultExecutor<PhysicalFileResult>, SymlinkFollowingPhysicalFileResultExecutor>();
             services.AddJellyfinApi(_serverApplicationHost.GetApiPluginAssemblies(), _serverConfigurationManager.GetNetworkConfiguration());
 
             services.AddJellyfinApiSwagger();