Fixed: Newznab default capabilities erroneously cached if indexer is unavailable.

src/NzbDrone.Core.Test/IndexerTests/NewznabTests/NewznabCapabilitiesProviderFixture.cs

@@ -1,9 +1,12 @@
-using FluentAssertions;
+using System;
+using System.Xml;
+using FluentAssertions;
 using Moq;
 using NUnit.Framework;
 using NzbDrone.Common.Http;
 using NzbDrone.Core.Indexers.Newznab;
 using NzbDrone.Core.Test.Framework;
+using NzbDrone.Test.Common;
 
 namespace NzbDrone.Core.Test.IndexerTests.NewznabTests
 {
@@ -64,5 +67,35 @@ namespace NzbDrone.Core.Test.IndexerTests.NewznabTests
             caps.DefaultPageSize.Should().Be(100);
             caps.MaxPageSize.Should().Be(100);
         }
+
+        [Test]
+        public void should_throw_if_failed_to_get()
+        {
+            Mocker.GetMock<IHttpClient>()
+                .Setup(o => o.Get(It.IsAny<HttpRequest>()))
+                .Throws<Exception>();
+
+            Assert.Throws<Exception>(() => Subject.GetCapabilities(_settings));
+        }
+
+        [Test]
+        public void should_throw_if_xml_invalid()
+        {
+            GivenCapsResponse(_caps.Replace("<limits", "<>"));
+
+            Assert.Throws<XmlException>(() => Subject.GetCapabilities(_settings));
+        }
+
+        [Test]
+        public void should_not_throw_on_xml_data_unexpected()
+        {
+            GivenCapsResponse(_caps.Replace("5030", "asdf"));
+
+            var result = Subject.GetCapabilities(_settings);
+
+            result.Should().NotBeNull();
+
+            ExceptionVerification.ExpectedErrors(1);
+        }
     }
 }

src/NzbDrone.Core/Indexers/Newznab/NewznabCapabilitiesProvider.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Generic;
+using System.Net;
+using System.Xml;
 using System.Xml.Linq;
 using NLog;
 using NzbDrone.Common.Cache;
@@ -48,15 +50,30 @@ namespace NzbDrone.Core.Indexers.Newznab
 
             var request = new HttpRequest(url, HttpAccept.Rss);
 
+            HttpResponse response;
+
             try
             {
-                var response = _httpClient.Get(request);
+                response = _httpClient.Get(request);
+            }
+            catch (Exception ex)
+            {
+                _logger.Debug(ex, "Failed to get newznab api capabilities from {0}", indexerSettings.Url);
+                throw;
+            }
 
+            try
+            {
                 capabilities = ParseCapabilities(response);
             }
+            catch (XmlException ex)
+            {
+                _logger.Debug(ex, "Failed to parse newznab api capabilities for {0}.", indexerSettings.Url);
+                throw;
+            }
             catch (Exception ex)
             {
-                _logger.Debug(ex, string.Format("Failed to get capabilities from {0}: {1}", indexerSettings.Url, ex.Message));
+                _logger.Error(ex, "Failed to determine newznab api capabilities for {0}, using the defaults instead till Sonarr restarts.", indexerSettings.Url);
             }
 
             return capabilities;