NES (.NET Event Sourcing) is a lightweight framework that helps you build domain models when you're doing event sourcing.

If you're looking to take advantage of event sourcing on the .NET platform then you may also be looking to use NServiceBus and Jonathan Oliver's EventStore. NES is an attempt to fill in the gaps between these two frameworks.

The code required to bring NServiceBus and the EventStore together isn't hard to write but it is important and it does have to work a certain way to take full advantage of both frameworks. There's some great resources out there already that help you write this yourself but ideally you'd want to concentrate on developing your domain model's behaviour rather than the infrastructure to glue these two frameworks together.

NES hooks into NServiceBus' and the EventStore's configuration objects and transparently takes care of everything for you. All you have to do is add two extra lines to your application's initialisation code.

• Allow processing of messages sent in a batch as a single transaction (Ref)
• Allow use of interfaces for events (Ref)
• Allow up-conversion of events (Ref @ 36:00)
• Automatic persistence of message headers
• Automatic publishing of persisted events
• Convention based event handling within aggregates
• No 'Save()' methods on repositories
• Minimal configuration

• Supports EventStore v3
• Supports NServiceBus v3

• Supports EventStore v3
• Supports NServiceBus v2

• Supports EventStore v2
• Supports NServiceBus v2

The easiest way to install NES is via NuGet (NES, NES.EventStore, NES.EventStore.Raven, NES.NServiceBus) or you can download the source and run 'build.bat' from the command line. Once built, the files will be placed in the 'build' folder.

public class EndpointConfig : IConfigureThisEndpoint, AsA_Publisher, IWantCustomInitialization
{
	public void Init()
	{
		EventStore.Wireup.Init()
			.UsingSqlPersistence("EventStore")
			.InitializeStorageEngine()
			.NES()
			.UsingJsonSerialization()
			.Build();

		NServiceBus.Configure.With()
			.Log4Net()
			.DefaultBuilder()
			.XmlSerializer()
			.NES();
	}
}

For a more complete example, please open and build NES.Sample.sln in Visual Studio and hit F5. This will start the NES.Sample NServiceBus endpoint as well as the NES.Sample.Web MVC3 website.

• For guidance on how to use NES please take a look at the wiki pages.
• If you have any problems using NES please submit a new issue.
• Ask your question on Stack Overflow and tag your question with the CQRS tag and the word "NES" in the title.