From e39fee920999db0a3a188ce0ea61862ff825824d Mon Sep 17 00:00:00 2001
From: Taloth Saldono <Taloth@users.noreply.github.com>
Date: Sun, 3 May 2020 16:59:37 +0200
Subject: [PATCH] Skip unknown/removed commands still queued in the database

---
 .../Converters/CommandConverterFixture.cs     |  9 +++++++
 .../Datastore/Converters/CommandConverter.cs  |  6 ++++-
 .../Messaging/Commands/CommandExecutor.cs     |  3 +--
 .../Messaging/Commands/UnknownCommand.cs      | 11 +++++++++
 .../Commands/UnknownCommandExecutor.cs        | 24 +++++++++++++++++++
 5 files changed, 50 insertions(+), 3 deletions(-)
 create mode 100644 src/NzbDrone.Core/Messaging/Commands/UnknownCommand.cs
 create mode 100644 src/NzbDrone.Core/Messaging/Commands/UnknownCommandExecutor.cs

diff --git a/src/NzbDrone.Core.Test/Datastore/Converters/CommandConverterFixture.cs b/src/NzbDrone.Core.Test/Datastore/Converters/CommandConverterFixture.cs
index 633b92ce3..b66cd0896 100644
--- a/src/NzbDrone.Core.Test/Datastore/Converters/CommandConverterFixture.cs
+++ b/src/NzbDrone.Core.Test/Datastore/Converters/CommandConverterFixture.cs
@@ -3,6 +3,7 @@ using FluentAssertions;
 using NUnit.Framework;
 using NzbDrone.Core.Books.Commands;
 using NzbDrone.Core.Datastore.Converters;
+using NzbDrone.Core.Messaging.Commands;
 using NzbDrone.Core.Test.Framework;
 
 namespace NzbDrone.Core.Test.Datastore.Converters
@@ -42,6 +43,14 @@ namespace NzbDrone.Core.Test.Datastore.Converters
             Subject.Parse(data).Should().BeOfType<RefreshAuthorCommand>();
         }
 
+        [Test]
+        public void should_return_unknown_command_when_getting_json_from_db()
+        {
+            var data = "{\"name\": \"EnsureMediaCovers\"}";
+
+            Subject.Parse(data).Should().BeOfType<UnknownCommand>();
+        }
+
         [Test]
         public void should_return_null_for_null_value_when_getting_from_db()
         {
diff --git a/src/NzbDrone.Core/Datastore/Converters/CommandConverter.cs b/src/NzbDrone.Core/Datastore/Converters/CommandConverter.cs
index 6754b237c..e2f77c6f0 100644
--- a/src/NzbDrone.Core/Datastore/Converters/CommandConverter.cs
+++ b/src/NzbDrone.Core/Datastore/Converters/CommandConverter.cs
@@ -27,7 +27,11 @@ namespace NzbDrone.Core.Datastore.Converters
 
             if (impType == null)
             {
-                throw new CommandNotFoundException(contract);
+                var result = JsonSerializer.Deserialize<UnknownCommand>(stringValue, SerializerSettings);
+
+                result.ContractName = contract;
+
+                return result;
             }
 
             return (Command)JsonSerializer.Deserialize(stringValue, impType, SerializerSettings);
diff --git a/src/NzbDrone.Core/Messaging/Commands/CommandExecutor.cs b/src/NzbDrone.Core/Messaging/Commands/CommandExecutor.cs
index 2c9ea763e..18dabae07 100644
--- a/src/NzbDrone.Core/Messaging/Commands/CommandExecutor.cs
+++ b/src/NzbDrone.Core/Messaging/Commands/CommandExecutor.cs
@@ -69,8 +69,7 @@ namespace NzbDrone.Core.Messaging.Commands
 
             try
             {
-                var handlerContract = typeof(IExecute<>).MakeGenericType(command.GetType());
-                handler = (IExecute<TCommand>)_serviceFactory.Build(handlerContract);
+                handler = (IExecute<TCommand>)_serviceFactory.Build(typeof(IExecute<TCommand>));
 
                 _logger.Trace("{0} -> {1}", command.GetType().Name, handler.GetType().Name);
 
diff --git a/src/NzbDrone.Core/Messaging/Commands/UnknownCommand.cs b/src/NzbDrone.Core/Messaging/Commands/UnknownCommand.cs
new file mode 100644
index 000000000..fa579916e
--- /dev/null
+++ b/src/NzbDrone.Core/Messaging/Commands/UnknownCommand.cs
@@ -0,0 +1,11 @@
+namespace NzbDrone.Core.Messaging.Commands
+{
+    public class UnknownCommand : Command
+    {
+        public override bool SendUpdatesToClient => false;
+
+        public override string CompletionMessage => "Skipped";
+
+        public string ContractName { get; set; }
+    }
+}
diff --git a/src/NzbDrone.Core/Messaging/Commands/UnknownCommandExecutor.cs b/src/NzbDrone.Core/Messaging/Commands/UnknownCommandExecutor.cs
new file mode 100644
index 000000000..08fb2725d
--- /dev/null
+++ b/src/NzbDrone.Core/Messaging/Commands/UnknownCommandExecutor.cs
@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using NLog;
+
+namespace NzbDrone.Core.Messaging.Commands
+{
+    public class UnknownCommandExecutor : IExecute<UnknownCommand>
+    {
+        private readonly Logger _logger;
+
+        public UnknownCommandExecutor(Logger logger)
+        {
+            _logger = logger;
+        }
+
+        public void Execute(UnknownCommand message)
+        {
+            _logger.Debug("Ignoring unknown command {0}", message.ContractName);
+        }
+    }
+}