Fix Book collections scanning all items

Added static method GetBaseItemKindsForCollectionType in ItemsController (moved from ContentFolderImageProvider to be shared)

Added AudioBook to GetRepresentativeItemTypes for CollectionType.books for consistency

Added GetBooks to GetUserItems for CollectionType.books which gets BaseItemKind.Book and BaseItemKind.AudioBook

Move GetBaseItemKindsForCollectionType to DtoExtensions

Cleaned up the missing null checks and used new collection expressions.
Associate Person to Book and AudioBook for related items.

Emby.Server.Implementations/Dto/DtoService.cs

@@ -71,6 +71,8 @@ namespace Emby.Server.Implementations.Dto
             {
                 BaseItemKind.Person, [
                     BaseItemKind.Audio,
+                    BaseItemKind.AudioBook,
+                    BaseItemKind.Book,
                     BaseItemKind.Episode,
                     BaseItemKind.Movie,
                     BaseItemKind.LiveTvProgram,

Emby.Server.Implementations/Images/CollectionFolderImageProvider.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using Jellyfin.Api.Extensions;
 using Jellyfin.Data.Enums;
 using Jellyfin.Database.Implementations.Enums;
 using MediaBrowser.Common.Configuration;
@@ -14,7 +15,6 @@ using MediaBrowser.Controller.Entities;
 using MediaBrowser.Controller.Providers;
 using MediaBrowser.Model.Entities;
 using MediaBrowser.Model.IO;
-using MediaBrowser.Model.Querying;
 
 namespace Emby.Server.Implementations.Images
 {
@@ -28,38 +28,7 @@ namespace Emby.Server.Implementations.Images
         {
             var view = (CollectionFolder)item;
             var viewType = view.CollectionType;
-
+            var includeItemTypes = DtoExtensions.GetBaseItemKindsForCollectionType(viewType);
-            BaseItemKind[] includeItemTypes;
-
-            switch (viewType)
-            {
-                case CollectionType.movies:
-                    includeItemTypes = new[] { BaseItemKind.Movie };
-                    break;
-                case CollectionType.tvshows:
-                    includeItemTypes = new[] { BaseItemKind.Series };
-                    break;
-                case CollectionType.music:
-                    includeItemTypes = new[] { BaseItemKind.MusicArtist };  // Music albums usually don't have dedicated backdrops, so use artist instead
-                    break;
-                case CollectionType.musicvideos:
-                    includeItemTypes = new[] { BaseItemKind.MusicVideo };
-                    break;
-                case CollectionType.books:
-                    includeItemTypes = new[] { BaseItemKind.Book, BaseItemKind.AudioBook };
-                    break;
-                case CollectionType.boxsets:
-                    includeItemTypes = new[] { BaseItemKind.BoxSet };
-                    break;
-                case CollectionType.homevideos:
-                case CollectionType.photos:
-                    includeItemTypes = new[] { BaseItemKind.Video, BaseItemKind.Photo };
-                    break;
-                default:
-                    includeItemTypes = new[] { BaseItemKind.Video, BaseItemKind.Audio, BaseItemKind.Photo, BaseItemKind.Movie, BaseItemKind.Series };
-                    break;
-            }
-
             var recursive = viewType != CollectionType.playlists;
 
             return view.GetItemList(new InternalItemsQuery
@@ -67,12 +36,9 @@ namespace Emby.Server.Implementations.Images
                 CollapseBoxSetItems = false,
                 Recursive = recursive,
                 DtoOptions = new DtoOptions(false),
-                ImageTypes = new[] { ImageType.Primary },
+                ImageTypes = [ImageType.Primary],
                 Limit = 8,
-                OrderBy = new[]
+                OrderBy = [(ItemSortBy.Random, SortOrder.Ascending)],
-                {
-                    (ItemSortBy.Random, SortOrder.Ascending)
-                },
                 IncludeItemTypes = includeItemTypes
             });
         }

Jellyfin.Api/Controllers/ItemsController.cs

@@ -287,6 +287,8 @@ public class ItemsController : BaseJellyfinApiController
         QueryResult<BaseItem> result;
 
         Guid[] linkedChildAncestorIds = [];
+
+        includeItemTypes ??= [];
         if (includeItemTypes.Length == 1
             && (includeItemTypes[0] == BaseItemKind.BoxSet || includeItemTypes[0] == BaseItemKind.Playlist)
             && item is not BoxSet
@@ -314,6 +316,7 @@ public class ItemsController : BaseJellyfinApiController
         if (folder is IHasCollectionType hasCollectionType)
         {
             collectionType = hasCollectionType.CollectionType;
+            includeItemTypes = [.. includeItemTypes.Union(DtoExtensions.GetBaseItemKindsForCollectionType(collectionType))];
         }
 
         if (collectionType == CollectionType.playlists)

Jellyfin.Api/Extensions/DtoExtensions.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Jellyfin.Data.Enums;
 using MediaBrowser.Controller.Dto;
 using MediaBrowser.Model.Entities;
 
@@ -9,6 +10,35 @@ namespace Jellyfin.Api.Extensions;
 /// </summary>
 public static class DtoExtensions
 {
+    /// <summary>
+    /// Gets the BaseItemKind values associated with the specified CollectionType.
+    /// </summary>
+    /// <param name="collectionType">The collection type to map to BaseItemKind values.</param>
+    /// <returns>An array of BaseItemKind values that correspond to the collection type.</returns>
+    public static BaseItemKind[] GetBaseItemKindsForCollectionType(CollectionType? collectionType)
+    {
+        switch (collectionType)
+        {
+            case CollectionType.movies:
+                return [BaseItemKind.Movie];
+            case CollectionType.tvshows:
+                return [BaseItemKind.Series];
+            case CollectionType.music:
+                return [BaseItemKind.MusicAlbum, BaseItemKind.MusicArtist];
+            case CollectionType.musicvideos:
+                return [BaseItemKind.MusicVideo];
+            case CollectionType.books:
+                return [BaseItemKind.Book, BaseItemKind.AudioBook];
+            case CollectionType.boxsets:
+                return [BaseItemKind.BoxSet];
+            case CollectionType.homevideos:
+            case CollectionType.photos:
+                return [BaseItemKind.Video, BaseItemKind.Photo];
+            default:
+                return [BaseItemKind.Video, BaseItemKind.Audio, BaseItemKind.Photo, BaseItemKind.Movie, BaseItemKind.Series];
+        }
+    }
+
     /// <summary>
     /// Add additional DtoOptions.
     /// </summary>

MediaBrowser.Controller/Entities/UserViewBuilder.cs

@@ -61,6 +61,9 @@ namespace MediaBrowser.Controller.Entities
                 case CollectionType.folders:
                     return GetResult(_libraryManager.GetUserRootFolder().GetChildren(user, true), query);
 
+                case CollectionType.books:
+                    return GetBooks(queryParent, user, query);
+
                 case CollectionType.tvshows:
                     return GetTvView(queryParent, user, query);
 
@@ -190,6 +193,17 @@ namespace MediaBrowser.Controller.Entities
             return _libraryManager.GetItemsResult(query);
         }
 
+        private QueryResult<BaseItem> GetBooks(Folder parent, User user, InternalItemsQuery query)
+        {
+            query.Recursive = true;
+            query.Parent = parent;
+            query.SetUser(user);
+
+            query.IncludeItemTypes = new[] { BaseItemKind.Book, BaseItemKind.AudioBook };
+
+            return _libraryManager.GetItemsResult(query);
+        }
+
         private QueryResult<BaseItem> GetMovieMovies(Folder parent, User user, InternalItemsQuery query)
         {
             query.Recursive = true;