Apply review suggestions and fix bug

Jellyfin.Data/Entities/User.cs

@@ -420,10 +420,7 @@ namespace Jellyfin.Data.Entities
         /// <returns>A string array containing the user's preferences.</returns>
         public string[] GetPreference(PreferenceKind preference)
         {
-            var val = Preferences
-                .Where(p => p.Kind == preference)
-                .Select(p => p.Value)
-                .First();
+            var val = Preferences.First(p => p.Kind == preference).Value;
 
             return Equals(val, string.Empty) ? Array.Empty<string>() : val.Split(Delimiter);
         }

Jellyfin.Server.Implementations/Users/UserManager.cs

@@ -84,24 +84,10 @@ namespace Jellyfin.Server.Implementations.Users
         public event EventHandler<GenericEventArgs<User>> OnUserLockedOut;
 
         /// <inheritdoc/>
-        public IEnumerable<User> Users
-        {
-            get
-            {
-                var dbContext = _dbProvider.CreateContext();
-                return dbContext.Users;
-            }
-        }
+        public IEnumerable<User> Users => _dbProvider.CreateContext().Users;
 
         /// <inheritdoc/>
-        public IEnumerable<Guid> UsersIds
-        {
-            get
-            {
-                var dbContext = _dbProvider.CreateContext();
-                return dbContext.Users.Select(u => u.Id);
-            }
-        }
+        public IEnumerable<Guid> UsersIds => _dbProvider.CreateContext().Users.Select(u => u.Id);
 
         /// <inheritdoc/>
         public User GetUserById(Guid id)
@@ -111,9 +97,7 @@ namespace Jellyfin.Server.Implementations.Users
                 throw new ArgumentException("Guid can't be empty", nameof(id));
             }
 
-            var dbContext = _dbProvider.CreateContext();
-
-            return dbContext.Users.Find(id);
+            return _dbProvider.CreateContext().Users.Find(id);
         }
 
         /// <inheritdoc/>
@@ -124,11 +108,9 @@ namespace Jellyfin.Server.Implementations.Users
                 throw new ArgumentException("Invalid username", nameof(name));
             }
 
-            var dbContext = _dbProvider.CreateContext();
-
             // This can't use an overload with StringComparer because that would cause the query to
             // have to be evaluated client-side.
-            return dbContext.Users.FirstOrDefault(u => string.Equals(u.Username, name));
+            return _dbProvider.CreateContext().Users.FirstOrDefault(u => string.Equals(u.Username, name));
         }
 
         /// <inheritdoc/>

MediaBrowser.Controller/Entities/Folder.cs

@@ -182,12 +182,13 @@ namespace MediaBrowser.Controller.Entities
         {
             if (this is ICollectionFolder && !(this is BasePluginFolder))
             {
-                if (user.GetPreference(PreferenceKind.BlockedMediaFolders) != null)
+                var blockedMediaFolders = user.GetPreference(PreferenceKind.BlockedMediaFolders);
+                if (blockedMediaFolders.Length > 0)
                 {
-                    if (user.GetPreference(PreferenceKind.BlockedMediaFolders).Contains(Id.ToString("N", CultureInfo.InvariantCulture), StringComparer.OrdinalIgnoreCase) ||
+                    if (blockedMediaFolders.Contains(Id.ToString("N", CultureInfo.InvariantCulture), StringComparer.OrdinalIgnoreCase) ||
 
                         // Backwards compatibility
-                        user.GetPreference(PreferenceKind.BlockedMediaFolders).Contains(Name, StringComparer.OrdinalIgnoreCase))
+                        blockedMediaFolders.Contains(Name, StringComparer.OrdinalIgnoreCase))
                     {
                         return false;
                     }