Failed Download detection now ignores history without unique download client id.

src/NzbDrone.Common/DictionaryExtensions.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NzbDrone.Common
+{
+    public static class DictionaryExtensions
+    {
+        public static TValue GetValueOrDefault<TKey, TValue>(this IDictionary<TKey, TValue> dictionary, TKey key, TValue defaultValue = default(TValue))
+        {
+            TValue value;
+            return dictionary.TryGetValue(key, out value) ? value : defaultValue;
+        }
+    }
+}

src/NzbDrone.Common/NzbDrone.Common.csproj

@@ -67,6 +67,7 @@
     <Compile Include="Composition\IContainer.cs" />
     <Compile Include="Composition\ContainerBuilderBase.cs" />
     <Compile Include="DateTimeExtensions.cs" />
+    <Compile Include="DictionaryExtensions.cs" />
     <Compile Include="Disk\DiskProviderBase.cs" />
     <Compile Include="EnsureThat\Ensure.cs" />
     <Compile Include="EnsureThat\EnsureBoolExtensions.cs" />

src/NzbDrone.Core.Test/Download/FailedDownloadServiceFixture.cs

@@ -131,6 +131,54 @@ namespace NzbDrone.Core.Test.Download
             VerifyNoFailedDownloads();
         }
 
+        [Test]
+        public void should_not_process_if_grabbed_history_contains_null_downloadclient_id()
+        {
+            GivenFailedDownloadClientHistory();
+
+            var historyGrabbed = Builder<History.History>.CreateListOfSize(1)
+                                                  .Build()
+                                                  .ToList();
+
+            historyGrabbed.First().Data.Add("downloadClient", "SabnzbdClient");
+            historyGrabbed.First().Data.Add("downloadClientId", null);
+
+            GivenGrabbedHistory(historyGrabbed);
+            GivenNoFailedHistory();
+
+            Subject.Execute(new CheckForFailedDownloadCommand());
+
+            VerifyNoFailedDownloads();
+        }
+
+        [Test]
+        public void should_process_if_failed_history_contains_null_downloadclient_id()
+        {
+            GivenFailedDownloadClientHistory();
+
+            var historyGrabbed = Builder<History.History>.CreateListOfSize(1)
+                                                  .Build()
+                                                  .ToList();
+
+            historyGrabbed.First().Data.Add("downloadClient", "SabnzbdClient");
+            historyGrabbed.First().Data.Add("downloadClientId", _failed.First().Id);
+
+            GivenGrabbedHistory(historyGrabbed);
+
+            var historyFailed = Builder<History.History>.CreateListOfSize(1)
+                                                  .Build()
+                                                  .ToList();
+
+            historyFailed.First().Data.Add("downloadClient", "SabnzbdClient");
+            historyFailed.First().Data.Add("downloadClientId", null);
+            
+            GivenFailedHistory(historyFailed);
+
+            Subject.Execute(new CheckForFailedDownloadCommand());
+
+            VerifyFailedDownloads();
+        }
+
         [Test]
         public void should_not_process_if_already_added_to_history_as_failed()
         {

src/NzbDrone.Core/Download/FailedDownloadService.cs

@@ -1,6 +1,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using NLog;
+using NzbDrone.Common;
 using NzbDrone.Core.Configuration;
 using NzbDrone.Core.History;
 using NzbDrone.Core.Messaging.Commands;
@@ -72,8 +73,7 @@ namespace NzbDrone.Core.Download
                     continue;
                 }
 
-                if (failedHistory.Any(h => h.Data.ContainsKey(DOWNLOAD_CLIENT_ID) &&
+                if (failedHistory.Any(h => failedLocal.Id.Equals(h.Data.GetValueOrDefault(DOWNLOAD_CLIENT_ID))))
-                                           h.Data[DOWNLOAD_CLIENT_ID].Equals(failedLocal.Id)))
                 {
                     _logger.Trace("Already added to history as failed");
                     continue;
@@ -118,8 +118,7 @@ namespace NzbDrone.Core.Download
                     continue;
                 }
 
-                if (failedHistory.Any(h => h.Data.ContainsKey(DOWNLOAD_CLIENT_ID) &&
+                if (failedHistory.Any(h => failedLocal.Id.Equals(h.Data.GetValueOrDefault(DOWNLOAD_CLIENT_ID))))
-                                           h.Data[DOWNLOAD_CLIENT_ID].Equals(failedLocal.Id)))
                 {
                     _logger.Trace("Already added to history as failed");
                     continue;
@@ -137,8 +136,7 @@ namespace NzbDrone.Core.Download
 
         private List<History.History> GetHistoryItems(List<History.History> grabbedHistory, string downloadClientId)
         {
-            return grabbedHistory.Where(h => h.Data.ContainsKey(DOWNLOAD_CLIENT_ID) &&
+            return grabbedHistory.Where(h => downloadClientId.Equals(h.Data.GetValueOrDefault(DOWNLOAD_CLIENT_ID)))
-                                             h.Data[DOWNLOAD_CLIENT_ID].Equals(downloadClientId))
                                  .ToList();
         }
 
@@ -148,17 +146,14 @@ namespace NzbDrone.Core.Download
             string downloadClient;
             string downloadClientId;
 
-            historyItem.Data.TryGetValue(DOWNLOAD_CLIENT, out downloadClient);
-            historyItem.Data.TryGetValue(DOWNLOAD_CLIENT_ID, out downloadClientId);
-
             _eventAggregator.PublishEvent(new DownloadFailedEvent
             {
                 SeriesId = historyItem.SeriesId,
                 EpisodeIds = historyItems.Select(h => h.EpisodeId).ToList(),
                 Quality = historyItem.Quality,
                 SourceTitle = historyItem.SourceTitle,
-                DownloadClient = downloadClient,
+                DownloadClient = historyItem.Data.GetValueOrDefault(DOWNLOAD_CLIENT),
-                DownloadClientId = downloadClientId,
+                DownloadClientId = historyItem.Data.GetValueOrDefault(DOWNLOAD_CLIENT_ID),
                 Message = message
             });
         }