Fix Bigscreen compatibility issues (#83)

src/Jellyfin.Plugin.Dlna/Api/DlnaServerController.cs

@@ -4,6 +4,7 @@
 using System.IO;
 using System.Net.Mime;
 using System.Threading.Tasks;
+using Jellyfin.Extensions;
 using Jellyfin.Plugin.Dlna.Model;
 using MediaBrowser.Common.Api;
 using MediaBrowser.Model.Net;
@@ -21,6 +22,8 @@ namespace Jellyfin.Plugin.Dlna.Api;
 [Authorize(Policy = Policies.AnonymousLanAccessPolicy)]
 public class DlnaServerController : ControllerBase
 {
+    private static readonly string[] _relativePathUserAgents = { "Bigscreen" };
+
     private readonly IDlnaManager _dlnaManager;
     private readonly IContentDirectory _contentDirectory;
     private readonly IConnectionManager _connectionManager;
@@ -59,7 +62,15 @@ public DlnaServerController(
     [Produces(MediaTypeNames.Text.Xml)]
     public ActionResult<string> GetDescriptionXml([FromRoute, Required] string serverId)
     {
-        var url = GetAbsoluteUri();
+        var useRelativePath = false;
+        string? userAgent = Request.Headers.UserAgent;
+        if (userAgent is not null)
+        {
+            userAgent = userAgent.Substring(0, userAgent.IndexOf('/'));
+            useRelativePath = _relativePathUserAgents.Contains(userAgent, StringComparison.Ordinal);
+        }
+
+        var url = useRelativePath ? GetRelativePath() : GetAbsoluteUri();
         var serverAddress = url.Substring(0, url.IndexOf("/dlna/", StringComparison.OrdinalIgnoreCase));
         var xml = _dlnaManager.GetServerDescriptionXml(Request.Headers, serverId, serverAddress);
         return Ok(xml);
@@ -279,6 +290,11 @@ private string GetAbsoluteUri()
         return $"{Request.Scheme}://{Request.Host}{Request.PathBase}{Request.Path}";
     }
 
+    private string GetRelativePath()
+    {
+        return $"{Request.PathBase}{Request.Path}";
+    }
+
     private Task<ControlResponse> ProcessControlRequestInternalAsync(string id, Stream requestStream, IUpnpService service)
     {
         return service.ProcessControlRequestAsync(new ControlRequest(Request.Headers)

src/Jellyfin.Plugin.Dlna/ContentDirectory/ControlHandler.cs

@@ -681,11 +681,7 @@ private QueryResult<ServerItem> GetMusicFolders(BaseItem item, User user, StubTy
             new(item, StubType.FavoriteSongs)
         };
 
-        if (limit < serverItems.Length)
-        {
-            serverItems = serverItems[..limit.Value];
-        }
-
+        serverItems = GetTrimmedServerItemsArray(serverItems, startIndex, limit);
         return new QueryResult<ServerItem>(
             startIndex,
             serverItems.Length,
@@ -737,11 +733,7 @@ private QueryResult<ServerItem> GetMovieFolders(BaseItem item, User user, StubTy
             new(item, StubType.Genres)
         };
 
-        if (limit < array.Length)
-        {
-            array = array[..limit.Value];
-        }
-
+        array = GetTrimmedServerItemsArray(array, startIndex, limit);
         return new QueryResult<ServerItem>(
             startIndex,
             array.Length,
@@ -821,11 +813,7 @@ private QueryResult<ServerItem> GetTvFolders(BaseItem item, User user, StubType?
             new(item, StubType.Genres)
         };
 
-        if (limit < serverItems.Length)
-        {
-            serverItems = serverItems[..limit.Value];
-        }
-
+        serverItems = GetTrimmedServerItemsArray(serverItems, startIndex, limit);
         return new QueryResult<ServerItem>(
             startIndex,
             serverItems.Length,
@@ -1023,18 +1011,34 @@ private QueryResult<ServerItem> GetLatest(BaseItem parent, InternalItemsQuery qu
     {
         query.OrderBy = Array.Empty<(ItemSortBy, SortOrder)>();
 
+        int limit;
+
+        if (query.StartIndex > 0)
+        {
+            limit = (query.Limit <= 0) ? int.MaxValue : (query.StartIndex.Value + (query.Limit ?? 50));
+        }
+        else
+        {
+            limit = query.Limit ?? 50;
+        }
+
         var items = _userViewManager.GetLatestItems(
             new LatestItemsQuery
             {
                 // User cannot be null here as the caller has set it
                 User = query.User!,
-                Limit = query.Limit ?? 50,
+                Limit = limit,
                 IncludeItemTypes = new[] { itemType },
                 ParentId = parent?.Id ?? Guid.Empty,
                 GroupItems = true
             },
             query.DtoOptions).Select(i => i.Item1 ?? i.Item2.FirstOrDefault()).Where(i => i is not null).ToArray();
 
+        if (query.StartIndex > 0)
+        {
+            items = (items.Length <= query.StartIndex) ? Array.Empty<BaseItem>() : items[query.StartIndex.Value..];
+        }
+
         return ToResult(query.StartIndex, items);
     }
 
@@ -1243,4 +1247,31 @@ private ServerItem ParseItemId(string id)
 
         return new ServerItem(_libraryManager.GetUserRootFolder(), null);
     }
+
+    /// <summary>
+    /// Discards elements before startIndex and elements after startIndex+limit from an array of <see cref="ServerItem"/>.
+    /// </summary>
+    /// <param name="serverItems">An array of <see cref="ServerItem"/>.</param>
+    /// <param name="startIndex">The start index.</param>
+    /// <param name="limit">The maximum number to return.</param>
+    /// <returns>The corresponding trimmed array of <see cref="ServerItem"/></returns>
+    private static ServerItem[] GetTrimmedServerItemsArray(ServerItem[] serverItems, int? startIndex, int? limit)
+    {
+        if (startIndex >= serverItems.Length)
+        {
+            return Array.Empty<ServerItem>();
+        }
+
+        if (startIndex > 0)
+        {
+            serverItems = serverItems[startIndex.Value..];
+        }
+
+        if (limit < serverItems.Length)
+        {
+            serverItems = serverItems[..limit.Value];
+        }
+
+        return serverItems;
+    }
 }

src/Jellyfin.Plugin.Dlna/Server/DescriptionXmlBuilder.cs

@@ -23,7 +23,6 @@ public class DescriptionXmlBuilder
     public DescriptionXmlBuilder(DlnaDeviceProfile profile, string serverUdn, string serverAddress, string serverName, string serverId)
     {
         ArgumentException.ThrowIfNullOrEmpty(serverUdn);
-        ArgumentException.ThrowIfNullOrEmpty(serverAddress);
 
         _profile = profile;
         _serverUdn = serverUdn;