Registering WCF service in Unity Container

Question

I have a wcf service library that is hosted in a windows service. I need to intercept calls to Service methods. For this case it is suggested to register WCF into Unity container as can be seen in this link

http://weblogs.asp.net/fabio/archive/2009/03/24/inversion-of-control-with-wcf-and-unity.aspx

I am trying to implement a similar approach by Unity.WCF assembly from Codeplex.I could not understand where to put my container configuration or bootstrapper in wcf service library(or windows service). There is not a solid sample (vs solution) provided.

My Windows Service Host

    private UnityServiceHost _serviceHost = null;
    private readonly UnityContainer _container;


    public Service() {
        InitializeComponent();
        _container = new UnityContainer();
        _container.AddNewExtension<Interception>();
        _container.RegisterType<ISecurityRepository, SecurityRepository>();
        _container.Configure<Interception>().SetDefaultInterceptorFor<ISecurityRepository>(new TransparentProxyInterceptor());
    }

    protected override void OnStart(string[] args) {

        //SecurityService
        if (_serviceHost != null) {

            _serviceHost.Close();
        } else {
            _serviceHost = new UnityServiceHost(_container, typeof(SecurityRepository));
            _serviceHost.Open();
        }

    }

    protected override void OnStop() {

        //SecurityService
        if (_serviceHost != null) {

            _serviceHost.Close();
            _serviceHost = null;
        }
    }

My Service Contract

[ServiceContract(SessionMode = SessionMode.Required)]
public interface ISecurityRepository
{

    [OperationContract(IsInitiating = true)]
    IList<vNavigationTree> GetNavigationTree(string ticket);

    [OperationContract(IsInitiating = true)]
    string GetSessionGuid(string userName, string IP, string machineName);
}

In this case it seems that interceptor does not work. Briefly what I need is a sample project in which the WCF Service is registered to DI container and the Service methods are intercepted.

Answer 1

I will try to explain what I tried to do more explicitly and how I managed to do it. I have a WPF application communicating with a database via WCF which means my app is divided roughly in two: client-side and server-side (WCF). I have wrapped the client-side into a Unity container via the UnityBootStrapper provided by PRISM. I need to wrap the server-side into another Unity container as well, in order to make Unity resolve the server-side dependencies.

My problem is solved by Unity.WCF (available as a Nuget package) which provides the UnityServiceHost class which can be used instead of ServiceHost. I guess this package is created in the way this post explains:

http://weblogs.asp.net/fabio/archive/2009/03/24/inversion-of-control-with-wcf-and-unity.aspx

Answer 2

What you will need to do is take advantage of unity interception pipeline.

Unity provides a built-in policy injection behavior to facilitate the implementation of aop. The policy injection behavior attaches or injects some functionality to specific methods by using call handlers and matching rules on a per-method basis.

a. Start with a custom interface of a ICallhandler.

>>    public interface ILogAttributeHandler : ICallHandler
>>    {
>>    }
>>

b. Add you implementation for your handler. This is the advice you want to apply when your method is intercepted.

>>    public class ActivityAttributeHandler : ILogAttributeHandler
>>    {
>>    public ActivityAttributeHandler(string activityType)
>>    {
>>    ActivityType = activityType;
>>    }

>>    private string ActivityType { get; set; }
>>    public int Order { get; set; }

>>    public IMethodReturn Invoke(IMethodInvocation input, GetNextHandlerDelegate getNext)
>>    {
 >>           //// Invoke the handler
>>            IMethodReturn output = getNext()(input, getNext);

>>            //// Perform post-processing task
>>            var agent = output.ReturnValue as Agent;

>>            if (agent != null)
>>            {
>>               //// do work here 
>>            }

>>            return getNext()(input, getNext);
>>        }
}

c. Create your custom attribute, this will used as a pointcut in the program.

>>  [AttributeUsage(AttributeTargets.Method)]
>>   public class ActivityAttribute : HandlerAttribute
>>    {
>>        private readonly string _activityName;

 >>       public ActivityAttribute(string activityName)
>>        {
>>            _activityName = activityName;
>>        }
>> }
>>       public override ICallHandler CreateHandler(IUnityContainer container)
>>      {
>>  return null;
>>}

d. Now all you have left is to configure the interception within your unity configuration and add the attribute to your service interface operation that you want to be intercepted.

>  container
>                 .RegisterType<ILogAttributeHandler, LogAttributeHandler>()
>                 .AddNewExtension<Interception>()
>                 .Configure<Interception>()
>                .SetInterceptorFor<ISecurityRepository>("SecurityRepository", new
> InterfaceInterceptor());

e. Apply attributes to your interface operations

>>public interface ISecurityRepository 
>> {
>>    [OperationContract(IsInitiating = true)]
>>    [Activity("Logon")]
>>    IList<vNavigationTree> GetNavigationTree(string ticket)
>>}