Merge pull request #2288 from MediaBrowser/dev

Dev

1 files changed, 29 insertions, 4 deletions

diff --git a/Emby.Server.Implementations/Channels/ChannelManager.cs b/Emby.Server.Implementations/Channels/ChannelManager.cs
index 2ce880c93a..0df916ded3 100644
--- a/Emby.Server.Implementations/Channels/ChannelManager.cs
+++ b/Emby.Server.Implementations/Channels/ChannelManager.cs
@@ -326,7 +326,7 @@ namespace Emby.Server.Implementations.Channels
 
             if (requiresCallback != null)
             {
-                results = await GetChannelItemMediaSourcesInternal(requiresCallback, item.ExternalId, cancellationToken)
+                results = await GetChannelItemMediaSourcesInternal(requiresCallback, GetItemExternalId(item), cancellationToken)
                     .ConfigureAwait(false);
             }
             else
@@ -1075,6 +1075,18 @@ namespace Emby.Server.Implementations.Channels
             return result;
         }
 
+        private string GetItemExternalId(BaseItem item)
+        {
+            var externalId = item.ExternalId;
+
+            if (string.IsNullOrWhiteSpace(externalId))
+            {
+                externalId = item.GetProviderId("ProviderExternalId");
+            }
+
+            return externalId;
+        }
+
         private readonly SemaphoreSlim _resourcePool = new SemaphoreSlim(1, 1);
         private async Task<ChannelItemResult> GetChannelItems(IChannel channel,
             User user,
@@ -1096,7 +1108,11 @@ namespace Emby.Server.Implementations.Channels
                 {
                     if (_fileSystem.GetLastWriteTimeUtc(cachePath).Add(cacheLength) > DateTime.UtcNow)
                     {
-                        return _jsonSerializer.DeserializeFromFile<ChannelItemResult>(cachePath);
+                        var cachedResult = _jsonSerializer.DeserializeFromFile<ChannelItemResult>(cachePath);
+                        if (cachedResult != null)
+                        {
+                            return cachedResult;
+                        }
                     }
                 }
             }
@@ -1119,7 +1135,11 @@ namespace Emby.Server.Implementations.Channels
                     {
                         if (_fileSystem.GetLastWriteTimeUtc(cachePath).Add(cacheLength) > DateTime.UtcNow)
                         {
-                            return _jsonSerializer.DeserializeFromFile<ChannelItemResult>(cachePath);
+                            var cachedResult = _jsonSerializer.DeserializeFromFile<ChannelItemResult>(cachePath);
+                            if (cachedResult != null)
+                            {
+                                return cachedResult;
+                            }
                         }
                     }
                 }
@@ -1145,11 +1165,16 @@ namespace Emby.Server.Implementations.Channels
                 {
                     var categoryItem = _libraryManager.GetItemById(new Guid(folderId));
 
-                    query.FolderId = categoryItem.ExternalId;
+                    query.FolderId = GetItemExternalId(categoryItem);
                 }
 
                 var result = await channel.GetChannelItems(query, cancellationToken).ConfigureAwait(false);
 
+                if (result == null)
+                {
+                    throw new InvalidOperationException("Channel returned a null result from GetChannelItems");
+                }
+
                 if (!startIndex.HasValue && !limit.HasValue)
                 {
                     CacheResponse(result, cachePath);