Fixed: Indexer sites returning date as Retry-After header.

fixes #994

src/NzbDrone.Common/Http/TooManyRequestsException.cs

@@ -14,7 +14,18 @@ public TooManyRequestsException(HttpRequest request, HttpResponse response)
         {
             if (response.Headers.ContainsKey("Retry-After"))
             {
-                RetryAfter = TimeSpan.FromSeconds(int.Parse(response.Headers["Retry-After"].ToString()));
+                var retryAfter = response.Headers["Retry-After"].ToString();
+                int seconds;
+                DateTime date;
+
+                if (int.TryParse(retryAfter, out seconds))
+                {
+                    RetryAfter = TimeSpan.FromSeconds(seconds);
+                }
+                else if (DateTime.TryParse(retryAfter, out date))
+                {
+                    RetryAfter = date.ToUniversalTime() - DateTime.UtcNow;
+                }
             }
         }
     }

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

@@ -143,7 +143,28 @@ public void Download_report_should_trigger_indexer_backoff_on_http429_with_long_
             Assert.Throws<ReleaseDownloadException>(() => Subject.DownloadReport(_parseResult));
 
             Mocker.GetMock<IIndexerStatusService>()
-                .Verify(v => v.RecordFailure(It.IsAny<int>(), TimeSpan.FromMinutes(5)), Times.Once());
+                .Verify(v => v.RecordFailure(It.IsAny<int>(), TimeSpan.FromMinutes(5.0)), Times.Once());
+        }
+
+        [Test]
+        public void Download_report_should_trigger_indexer_backoff_on_http429_based_on_date()
+        {
+            var request = new HttpRequest("http://my.indexer.com");
+            var response = new HttpResponse(request, new HttpHeader(), new byte[0], (HttpStatusCode)429);
+            response.Headers["Retry-After"] = DateTime.UtcNow.AddSeconds(300).ToString("r");
+
+            var mock = WithUsenetClient();
+            mock.Setup(s => s.Download(It.IsAny<RemoteEpisode>()))
+                .Callback<RemoteEpisode>(v =>
+                {
+                    throw new ReleaseDownloadException(v.Release, "Error", new TooManyRequestsException(request, response));
+                });
+
+            Assert.Throws<ReleaseDownloadException>(() => Subject.DownloadReport(_parseResult));
+
+            Mocker.GetMock<IIndexerStatusService>()
+                .Verify(v => v.RecordFailure(It.IsAny<int>(),
+                    It.IsInRange<TimeSpan>(TimeSpan.FromMinutes(4.9), TimeSpan.FromMinutes(5.1), Range.Inclusive)), Times.Once());
         }
 
         [Test]