In my last post I had shown you how to create a self hosted windows service.
In this post I am going to walk through the process of adding an installer in a window service and how to use it for installation of window service.

1. Right click on SelfHostService project and add an installer class named as WindowServiceInstaller.cs
2. A class with following code snippet will be generated by default

namespace SelfHostService
{
    [RunInstaller(true)]
    public partial class WindowServiceInstaller : System.Configuration.Install.Installer
    {
        public WindowServiceInstaller()
        {
            InitializeComponent();
        }
    }
}

3. To install this SelfHostService executable, which contains a class that extend ServiceBase, we will require a ServiceProcessInstaller
4. MSDN description of the ServiceProcessInstaller class is

Installs an executable containing classes that extend ServiceBase. This class is called by installation utilities, such as InstallUtil.exe, when installing a service application.

5. Also we will require ServiceInstaller class. MSDN description of the ServiceInstaller class is

Installs a class that extends ServiceBase to implement a service. This class is called by the install utility when installing a service application.

6. Let us finish our tiny installer. A complete code would look like this

namespace SelfHostService
{
    [RunInstaller(true)]
    public partial class WindowServiceInstaller : System.Configuration.Install.Installer
    {
        private ServiceProcessInstaller process;
        private ServiceInstaller service;

        public WindowServiceInstaller()
        {
            process = new ServiceProcessInstaller();
            process.Account = ServiceAccount.LocalService;
            service = new ServiceInstaller();
            service.ServiceName = "Self Hosted Windows Service";
            service.Description = "This is a self hosted windows service and can accept messages on port 8082 through HTTP";
            Installers.Add(process);
            Installers.Add(service);
        }
    }
}

7. [RunInstaller(true)] attributes is used by installutil.exe to identify the correct installer
8. Compile the project. From command prompt, navigate to the path on your machine where InstallUtil.exe is located.
9. Run command >installutil SelfHostService.exe
10. Above command will install a window service. Now open Service Control Manager and start the service.

Thats all for this post. In next post I will show you how to create a MSI Installer file using a set up project.

Today I am going to show you how to host a WCF service in a managed environment such as windows service. Let us see how to achieve this through C#.
Here, I will first show you how to create a simple windows service and then how to host a WCF service in it.
I will also show you how to pass the external messages received on this service, to a host. I am going to use a singleton pattern to avoid the race condition while receiving messages concurrently.

1. Create a “Console Application” project named as “SelfHostService” using installed templates in Visual Studio
2. Delete Program.cs file from project
3. Add a new class named as SelfHostService.cs
4. Click Add Reference menu to open a Add Reference Dialog Box
5. Select System.ServiceProcess namespace to refer
6. ServiceBase class resides in this newly added namespace, which is required to create a service application. Derive SerivceBase class in SelfHostService class
7. Also add a reference to System.ServiceModel namespace
8. Now let us put some code in SelfHostService class

    public class SelfHostService : ServiceBase
    {
        public ServiceHost serviceHost = null;
        private bool startProcessing;        
        private static SelfHostService instance = null;
        private static readonly object padlock = new object();

        //a private constructor
        SelfHostService()
        {
            ServiceName = "Self Hosted Service";
        }

        //public static property to access the instance of the SelfHostService class
        public static SelfHostService Instance
        {
            get
            {
                lock (padlock)
                {
                    if (instance == null)
                        instance = new SelfHostService();

                    return instance;
                }
            }
        }
    }

9. In above code I have created a public property named Instance to provide a single instance of SelfHostService class
10. Now let us define a service contract IMessageListener

namespace SelfHostService
{
    public interface IMessageListener
    {
        bool AcceptMessages(string messsage);
    }
}

11. We will have to override OnStart() and OnStop() methods of ServiceBase class. These methods contains instructions to follow when service starts and stops respectively. Let us write a code for these methods

        protected override void OnStart(string[] args)
        {
             if (serviceHost != null)
                    serviceHost.Close();

                serviceHost = new ServiceHost(typeof(MessageListenerService));

                serviceHost.Open();

                var timer = new Timer();
                timer.Interval = 60000;
                timer.Elapsed += new ElapsedEventHandler(DoWork);
                timer.Start();
        }

        protected override void OnStop()
        {
            if (serviceHost != null)
            {
                serviceHost.Close();
                serviceHost = null;
            }
        }

12. DoWork method is a task assigned to a timer which has been initialized in OnStart() method. After every interval elapses, this method will get executed. So one can write any code which is to be performed repetitively by a window service.

        private void DoWork(object sender, ElapsedEventArgs e)
        {
            //Add code to do the intended work
        }

13. I will add a method to accept requests, received by MessageListenerService

        public bool AcceptExternalMessages(string message)
        {
            if (string.IsNullOrEmpty(message))
                return false;
            else
                return true;
        }

14. Now we will implement IMessageListener in MessageListenerService

    public class MessageListenerService : IMessageListener
    {
        public bool AcceptMessages(string message)
        {
            //Notify message to windows service
            return SelfHostService.Instance.AcceptExternalMessages(message);
        }
    }

15. We will have to configure the services’ base address, binding and contracts

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.serviceModel>    
	<services>
      <service name="SelfHostService.MessageListenerService" behaviorConfiguration="ServiceBehavior">
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8082/SelfHostService/Service"/>
          </baseAddresses>
        </host>
        
        <endpoint address="" binding="wsHttpBinding" contract="SelfHostService.IMessageListener" />
        
        <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
      </service>
    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior name="ServiceBehavior" >
          <serviceMetadata httpGetEnabled="true"/>
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
  </system.serviceModel>
</configuration>

In my next post I will write about how to install this service using InstallUtil.exe

Note: This code post is written in C# 6.0 in Visual Studio 2015