Running

When using Visual Studio 2015+ the NuGet packages should be restored automatically. If you find that they do not or if you are using an older version of Visual Studio please execute the following in a Visual Studio command prompt:

cd {extraction-folder}\Shuttle.Esb.Samples\Shuttle.DependencyInjection
nuget restore

Once you have opened the Shuttle.DependencyInjection.sln solution in Visual Studio set the following projects as startup projects:

• Shuttle.DependencyInjection.Client
• Shuttle.DependencyInjection.Server

Set Shuttle.Core.Host.exe as the Start external program option by navigating to the bin\debug folder of the server project for the Shuttle.DependencyInjection.Server project.

Implementation

By default Shuttle.Esb does not require a dependency injection container. Shuttle makes use of an IMessageHandlerFactory implementation to create message handlers. If no dependency injection container is required one could stick with the DefaultMessageHandlerFactory instantiated by default.

The DefaultMessageHandlerFactory requires message handlers that have a default (parameterless) constructor; else the instantiation of the handler will fail. In this guide we will use the WindsorContainer that is part of the Castle Project.

In this guide we’ll create the following projects:

• a Console Application called Shuttle.DependencyInjection.Client
• a Class Library called Shuttle.DependencyInjection.Server
• another Class Library called Shuttle.DependencyInjection.EMail that will contain a fake e-mail service implementation
• and another Class Library called Shuttle.DependencyInjection.Messages that will contain all our message classes

Messages

Create a new class library called Shuttle.DependencyInjection.Messages with a solution called Shuttle.DependencyInjection

Note: remember to change the Solution name.

RegisterMemberCommand

Rename the Class1 default file to RegisterMemberCommand and add a UserName property.

namespace Shuttle.DependencyInjection.Messages
{
	public class RegisterMemberCommand
	{
		public string UserName { get; set; }
	}
}

Client

Add a new Console Application to the solution called Shuttle.DependencyInjection.Client.

Install the Shuttle.Esb.Msmq nuget package.

This will provide access to the Msmq IQueue implementation and also include the required dependencies.

Add a reference to the Shuttle.DependencyInjection.Messages project.

Program

Implement the main client code as follows:

using System;
using Shuttle.Esb;
using Shuttle.DependencyInjection.Messages;

namespace Shuttle.DependencyInjection.Client
{
	class Program
	{
		static void Main(string[] args)
		{
			using (var bus = ServiceBus.Create().Start())
			{
				string userName;

				while (!string.IsNullOrEmpty(userName = Console.ReadLine()))
				{
					bus.Send(new RegisterMemberCommand
					{
						UserName = userName
					});
				}
			}
		}
	}
}

The message sent will have its IgnoreTilleDate set to 5 seconds into the future. You can have a look at the TransportMessage for more information on the message structure.

App.config

Create the shuttle configuration as follows:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
	<configSections>
		<section name='serviceBus' type="Shuttle.Esb.ServiceBusSection, Shuttle.Esb"/>
	</configSections>

	<serviceBus>
		<messageRoutes>
			<messageRoute uri="msmq://./shuttle-server-work">
				<add specification="StartsWith" value="Shuttle.DependencyInjection.Messages" />
			</messageRoute>
		</messageRoutes>		
	</serviceBus>
	
    <startup> 
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
</configuration>

This tells shuttle that all messages that are sent and have a type name starting with Shuttle.DependencyInjection.Messages should be sent to endpoint msmq://./shuttle-server-work.

E-Mail

To demonstrate the dependency injection we will create a fake e-mail service that we intend using in the server endpoint.

Add a new Class Library to the solution called Shuttle.DependencyInjection.EMail.

IEMailService

Add an interface called IEMailService and implement it as follows:

namespace Shuttle.DependencyInjection.EMail
{
	public interface IEMailService
	{
		void Send(string name);
	}
}

EMailService

Rename the default Class1 file to EMailService and implement the IEMailService interfaces as follows:

using System;
using System.Threading;

namespace Shuttle.DependencyInjection.EMail
{
	public class EMailService : IEMailService
	{
		public void Send(string name)
		{
			Console.WriteLine();
			Console.WriteLine("[SENDING E-MAIL] : name = '{0}'", name);
			Console.WriteLine();

			Thread.Sleep(3000); // simulate communication wait time

			Console.WriteLine();
			Console.WriteLine("[E-MAIL SENT] : name = '{0}'", name);
			Console.WriteLine();
		}
	}
}

Server

Add a new Class Library to the solution called Shuttle.DependencyInjection.Server.

Install both the Shuttle.Esb.Msmq and Shuttle.Esb.Castle nuget packages.

This will provide access to the Msmq IQueue implementation and also include the required dependencies.

It will also include the WindsorContainer implementation of the IMessageHandlerFactory.

Install the Shuttle.Core.Host nuget package.

The default mechanism used to host an endpoint is by using a Windows service. However, by using the Shuttle.Core.Host executable we are able to run the endpoint as a console application or register it as a Windows service for deployment.

Add references to both the Shuttle.DependencyInjection.Messages and Shuttle.DependencyInjection.EMail projects.

Host

Rename the default Class1 file to Host and implement the IHost and IDisposabe interfaces as follows:

using System;
using Castle.MicroKernel.Registration;
using Castle.Windsor;
using Shuttle.Core.Host;
using Shuttle.DependencyInjection.EMail;
using Shuttle.Esb.Castle;
using Shuttle.Esb;

namespace Shuttle.DependencyInjection.Server
{
	public class Host : IHost, IDisposable
	{
		private IServiceBus _bus;
		private WindsorContainer _container;

		public void Start()
		{
			_container = new WindsorContainer();

			_container.Register(Component.For<IEMailService>().ImplementedBy<EMailService>());

			// register all the message handler in this assembly
			_container.Register(
				Classes.FromThisAssembly()
				.BasedOn(typeof(IMessageHandler<>))
				.WithServiceFromInterface(typeof(IMessageHandler<>))
				.LifestyleTransient()
				);

			_bus = ServiceBus.Create(
				c => c.MessageHandlerFactory(new CastleMessageHandlerFactory(_container))
				).Start();
		}

		public void Dispose()
		{
			_bus.Dispose();
		}
	}
}

App.config

Add an Application Configuration File item to create the App.config and populate as follows:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
	<configSections>
		<section name='serviceBus' type="Shuttle.Esb.ServiceBusSection, Shuttle.Esb"/>
	</configSections>

	<serviceBus>
		<inbox
		   workQueueUri="msmq://./shuttle-server-work"
		   errorQueueUri="msmq://./shuttle-error" />
	</serviceBus>
</configuration>

RegisterMemberHandler

Add a new class called RegisterMemberHandler that implements the IMessageHandler<RegisterMemberCommand> interface as follows:

using System;
using Shuttle.Core.Infrastructure;
using Shuttle.DependencyInjection.EMail;
using Shuttle.Esb;
using Shuttle.DependencyInjection.Messages;

namespace Shuttle.DependencyInjection.Server
{
	public class RegisterMemberHandler : IMessageHandler<RegisterMemberCommand>
	{
		private readonly IEMailService _emailService;

		public RegisterMemberHandler(IEMailService emailService)
		{
			Guard.AgainstNull(emailService, "emailService");

			_emailService = emailService;
		}

		public void ProcessMessage(IHandlerContext<RegisterMemberCommand> context)
		{
			Console.WriteLine();
			Console.WriteLine("[MEMBER REGISTERED] : user name = '{0}'", context.Message.UserName);
			Console.WriteLine();

			_emailService.Send(context.Message.UserName);
		}
	}
}

This will write out some information to the console window. The injected e-mail service will also be invoked and you’ll see the result in the console window.

Set Shuttle.Core.Host.exe as the Start external program option by navigating to the bin\debug folder of the server project.

Run

Set both the client and server projects as the startup.

Execute

Execute the application.

The client application will wait for you to input a user name. For this example enter my user name and press enter:

You have now implemented dependency injection for message handlers.