Improved error message when nzb download contains an newznab error instead

Signed-off-by: Robin Dadswell <robin@dadswell.email>

src/NzbDrone.Common/Extensions/XmlExtensions.cs

@@ -11,5 +11,21 @@ namespace NzbDrone.Common.Extensions
         {
             return container.Descendants().Where(c => c.Name.LocalName.Equals(localName, StringComparison.InvariantCultureIgnoreCase));
         }
+
+        public static bool TryGetAttributeValue(this XElement element, string name, out string value)
+        {
+            var attr = element.Attribute(name);
+
+            if (attr != null)
+            {
+                value = attr.Value;
+                return true;
+            }
+            else
+            {
+                value = null;
+                return false;
+            }
+        }
     }
 }

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

@@ -1,4 +1,5 @@
 using System.IO;
+using FluentAssertions;
 using NUnit.Framework;
 using NzbDrone.Core.Download;
 using NzbDrone.Core.Test.Framework;
@@ -31,6 +32,17 @@ namespace NzbDrone.Core.Test.Download
             Assert.Throws<InvalidNzbException>(() => Subject.Validate(filename, fileContent));
         }
 
+        [Test]
+        public void should_throw_on_newznab_error()
+        {
+            var filename = "NewznabError";
+            var fileContent = GivenNzbFile(filename);
+
+            var ex = Assert.Throws<InvalidNzbException>(() => Subject.Validate(filename, fileContent));
+
+            ex.Message.Should().Contain("201 - Incorrect parameter");
+        }
+
         [Test]
         public void should_validate_nzb()
         {

src/NzbDrone.Core.Test/Files/Nzbs/NewznabError.nzb

@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<error code="201" description="Incorrect parameter" />

src/NzbDrone.Core/Download/NzbValidationService.cs

@@ -1,3 +1,4 @@
+using System;
 using System.IO;
 using System.Linq;
 using System.Xml;
@@ -27,6 +28,14 @@ namespace NzbDrone.Core.Download
                     throw new InvalidNzbException("Invalid NZB: No Root element [{0}]", filename);
                 }
 
+                // nZEDb has an bug in their error reporting code spitting out invalid http status codes
+                if (nzb.Name.LocalName.Equals("error") &&
+                    nzb.TryGetAttributeValue("code", out var code) &&
+                    nzb.TryGetAttributeValue("description", out var description))
+                {
+                    throw new InvalidNzbException("Invalid NZB: Contains indexer error: {0} - {1}", code, description);
+                }
+
                 if (!nzb.Name.LocalName.Equals("nzb"))
                 {
                     throw new InvalidNzbException("Invalid NZB: Unexpected root element. Expected 'nzb' found '{0}' [{1}]", nzb.Name.LocalName, filename);