Unity Interception using auto wiring - asp.net-mvc

I got Unity interception working using a HadlerAttribute and an instance of ICallHandler. To get it working all I have to do is decorate the class with the [Trace] attribute, and the interceptor works great.
[Trace]
public interface IPersonService
{
string GetPerson();
}
However I would like to have interception working for all my methods in a couple of assemblies. So I am using Unity AutoRegistration to set up my container as follows:
private static IUnityContainer BuildUnityContainer()
{
var container = new UnityContainer();
//container.AddNewExtension<UnityInterfaceInterceptionRegisterer>();
container.
ConfigureAutoRegistration().
ExcludeSystemAssemblies().
LoadAssemblyFrom(typeof(PersonService).Assembly.Location).
Include(If.ImplementsITypeName, Then.Register()).
ApplyAutoRegistration();
return container;
}
Works great, except when I attempt to setup global registration as per this post:
http://unity.codeplex.com/discussions/281022
I have a UnityContainerExtension configured as follows, where MVC4Unity is my DLL:
public class UnityInterfaceInterceptionRegisterer : UnityContainerExtension
{
protected override void Initialize()
{
base.Container.AddNewExtension<Interception>();
base.Container.Configure<Interception>().
AddPolicy("LoggingPolicy").
AddMatchingRule<AssemblyMatchingRule>
(new InjectionConstructor("MVC4Unity")).
AddCallHandler(new TraceCallHandler());
base.Context.Registering += new EventHandler<RegisterEventArgs>(this.OnRegister);
}
private void OnRegister(object sender, RegisterEventArgs e)
{
IUnityContainer container = sender as IUnityContainer;
if (e != null && e.TypeFrom != null && e.TypeFrom.IsInterface)
{
container.Configure<Interception>()
.SetInterceptorFor(e.TypeFrom, e.Name, new InterfaceInterceptor());
}
}
}
Unfortunately it is always throwing a StackOverflowException (!) when it goes into the OnRegister method.
The question then is, has anyone implemented assembly or even namespace wide interception using Unity, and was this the way to go?
[EDIT]
It seems that no matter what I add in the AddMatchingRule line below, that the OnRegister handler is invoked for all included assemblies as well! ( for example even the Microsoft.* namespace assemblies!)
base.Container.AddNewExtension<Interception>();
base.Container.Configure<Interception>().
AddPolicy("LoggingPolicy").
// see what other types of matchings rules there are!
AddMatchingRule<NamespaceMatchingRule>
(new InjectionConstructor("MVC4Unity.*")).
AddCallHandler(new TraceCallHandler());
base.Context.Registering += new EventHandler<RegisterEventArgs>(this.OnRegister);

I'm late with my answer, but maybe someone will find this useful.
If I understood the problem correctly you need to apply one matching rule to multiple assemblies. For these kind of tasks you can use AssemblyMatchingRule (MSDN).
container.Configure<Interception>()
.AddPolicy("logging")
.AddMatchingRule<AssemblyMatchingRule>(
new InjectionConstructor(
new InjectionParameter("YourAssemblyName")))
.AddCallHandler<LoggingCallHandler>(
new ContainerControlledLifetimeManager(),
new InjectionConstructor(), new InjectionProperty("Order", 1));
In your last code snippet i think you need to remove dot asterisk in the end of namespace in order to add MVC4Unity namespace to your NamespaceMatchingRule.
For additional information please check this link - Policy Injection MSDN

Related

StructureMap: How to send the container to a class that has a Constructor that does not accept Parameters

I am trying to find out how I can pass the StructrueMap container to a class that I wrote that inherits from another (MS-Class).
namespace TheNamespace
{
public class DatabaseIssuerNameRegistry : ValidatingIssuerNameRegistry
{
/* **This can't be done**
public DatabaseIssuerNameRegistry(IPortalTenantManager portalTenantManager)
{
_someField= portalTenantManager;
}*/
protected override bool IsThumbprintValid(string thumbprint, string issuer)
{
//How does it work ???????????
var portalTenantManager = container.GetInstance<IPortalTenantManager>();
//Do something with the portalTenantManager
}
}
I need portalTenantManager to be the Instance that I have defined in my container in the Global.asax.
My Global Assax has these things setup:
protected void Application_Start()
{
var container = new Container();
container.Configure(x =>
{ ....
....
x.For<IPortalTenantManager>().Use<PortalTenantManager>();
});
...
...
ControllerBuilder.Current.SetControllerFactory(new StructureMapControllerFactory(container));
...
GlobalConfiguration.Configuration.DependencyResolver = new StructureMapApiControllerFactory(container);
...
}
Edit:
Because of the comments of #NightOwl888 I'll explain a bit further what this class does. (Hopefully explaining so why my hands are tied)
My application is able to authenticate a user with Azure Active Directory and is Multi-tenant capable. In the authentication pipeline I have the possibility to store the validation endpoints in my database instead of the default way on the web.config file. See MSDN
and this, which actually is explaining exactly what I'm doing.
So I registered my class in the web.config under the Tag issuerNameRegistry. At some point of the validation pipeline my class is instantiated and the overriden method IsThumbprintValid is beeing called. The problem is that the class registered in issuerNameRegistry expects a parameterless constructor (there it is! the constrained construction!), therefore I cannot create a constructor that would solve my problem.
Thanks for your help
It turns out that this question has been asked before on MSDN, the answer of which was provided by Travis Spencer in 2 different posts.
it is typical in my experience to have a single container and use that service- or Web-side-wide. In the startup of the service or Web app, you can create the container, register the dependencies, new up an instance of your SecurityTokenServiceConfiguration class, resolve your dependencies, use it to punch out a SecurityTokenService object, and host it.
After the first beta, we really pushed for DI support. We got a little hook in beta 2. You can now create a custom SecurityTokenServiceConfiguration class that overrides the virtual CreateSecurityTokenService method. The implementation in Microsoft's SecurityTokenServiceConfiguration does Activator.CreateInstance; yours can do IoC. This can include the resolution of an IssuerNameRegistiry. Something like this perhaps:
RequestSecurityTokenResponse Issue(IClaimsPrincipal principal, RequestSecurityToken request)
{
SecurityTokenServiceConfiguration config = new MyGoodSecurityTokenServiceConfiguration();
SecurityTokenService sts = config.CreateSecurityTokenService();
RequestSecurityTokenResponse rstr = sts.Issue(principal, request);
return rstr;
}
public class MyGoodSecurityTokenServiceConfiguration : SecurityTokenServiceConfiguration
{
public override SecurityTokenService CreateSecurityTokenService()
{
IssuerNameRegistry = IoC.Resolve<IssuerNameRegistry>();
var sts = IoC.Reslove<SecurityTokenService>();
return sts;
}
}
Of course, this means that you need to create a static instance of your DI container so it is accessible to your SecurityTokenServiceConfiguration class. Personally, I don't like that idea because it makes your DI container accessible throughout the application, which can lead to abuse of the DI container as a service locator.
Ideally, there would be a way in any DI friendly framework to pass the container into an abstract factory in order to resolve service dependencies. However, since I am not familiar with WIF it is unclear whether that can be done - perhaps the class where the Issue method exists could have a constructor added? The trick is to keep walking up the chain until you find the first place in the framework where you can intervene and do all of your DI configuration there.

Simple Injector manually registering controllers

I'm attempting to implement Dependency Injection into my architecture (MVC, DDD - Domain Model, Repository). And my architecture includes ASP.NET Identity 2.0.
At this stage, I don't want DI controlling any of the Identity 2.0 objects (UserAdminController, RolesAdminController...). I'd prefer the security objects outside of DI. At this stage, integrating the Identity objects in DI looks very difficult. I had a good look to see if someone has already done this, so I could read and learn how to do this. I couldn't find anything. (Found one post which came close, but no resolution).
Anyway, I've followed the Simple Injector MVC implementation (see standard code below), and trying many things, I believe the problem lies in me calling RegisterMvcControllers.
Correct me if I'm wrong, but this statement will pickup all controllers with their name post-fixed with "controller".
Question: How can I select which controllers get registered with Simple Injector? (Is this called manually registering?)
Any help would be greatly appreciated, as I've spent most of today trying to get my head around all this, and proceed to the next step, i.e. have DI implemented, and instantiating my objects.
...
...
... called from Application_Start()
// Create a Simple Injector container
var container = new Container();
// Configure the container
InitializeContainer(container);
container.RegisterMvcControllers(Assembly.GetExecutingAssembly());
// Verify the container's configuration
container.Verify();
DependencyResolver.SetResolver(new SimpleInjectorDependencyResolver(container));
private static void InitializeContainer(Container container)
{
container.Register<MyService1>();
container.Register<IMyRepositoryA, MyRepositoryA>();
// Trying to include Identity into Simple Injector - please ignore
container.Register<IUserStore<ApplicationUser>>(() => new UserStore<ApplicationUser>(new ApplicationDbContext()));
}
The RegisterMvcControllers has the following constraints on the types it registers:
The type must be public
The type must implement System.Web.Mvc.IController
The type must not be abstract
The type must not be a generic type definition
Its name must end with "Controller"
You can see what happens here in the source code.
The RegisterMvcControllers extension method calls into the SimpleInjectorMvcExtensions.GetControllerTypesToRegister method to get the list of controllers to register. You can call that method yourself to see what is registered as follows:
var registeredControllerTypes =
SimpleInjectorMvcExtensions.GetControllerTypesToRegister(
container, Assembly.GetExecutingAssembly())
So instead of calling RegisterMvcControllers you can register the controllers yourself by calling the GetControllerTypesToRegister method:
var registeredControllerTypes =
SimpleInjectorMvcExtensions.GetControllerTypesToRegister(
container, Assembly.GetExecutingAssembly());
foreach (var controllerType in registeredControllerTypes)
{
container.Register(controllerType, controllerType, Lifestyle.Transient);
}
This way you can filter out any controller you want to register manually:
var registeredControllerTypes =
SimpleInjectorMvcExtensions.GetControllerTypesToRegister(
container, Assembly.GetExecutingAssembly())
.Where(type => type.Name != "UserStore`1");
foreach (var controllerType in registeredControllerTypes)
{
container.Register(controllerType, controllerType, Lifestyle.Transient);
}
Another option is to override the registration:
container.RegisterMvcControllers(Assembly.GetExecutingAssembly());
container.Options.AllowOverridingRegistrations = true;
container.Register<IUserStore<ApplicationUser>>(
() => new UserStore<ApplicationUser>(new ApplicationDbContext()))
// Always set the option back to false ASAP to prevent configuration errors.
container.Options.AllowOverridingRegistrations = false;

Using Ninject with Udi Dahan's Domain Events

I'm using Ninject in an MVC project and am trying to implement Domain Events following Udi Dahan's pattern http://www.udidahan.com/2009/06/14/domain-events-salvation/
In the extract below, the "Container" is used to resolve all the event-handlers for the particular type of event that has been raised.
My question (& apologies if I am missing something basic) is how to do this with Ninject? In other words:
How does the "Container" get set in this static class?
Once I have a Container (Kernel?) what would be the Ninject syntax to resolve all the event handlers (which I'm assuming I would have to register before-hand in a Service Module)?
I keep reading in posts that only constructor injection should be used and everything recursively get resolved from that, and that accessing the Ninject Kernel is a no-no. So any advice on how to do this will be much appreciated.
Extract from the article
public static class DomainEvents
{
[ThreadStatic] //so that each thread has its own callbacks
private static List<Delegate> actions;
public static IContainer Container { get; set; } //as before
//Registers a callback for the given domain event
public static void Register<T>(Action<T> callback) where T : IDomainEvent
{
if (actions == null)
actions = new List<Delegate>();
actions.Add(callback);
}
//Clears callbacks passed to Register on the current thread
public static void ClearCallbacks ()
{
actions = null;
}
//Raises the given domain event
public static void Raise<T>(T args) where T : IDomainEvent
{
if (Container != null)
foreach(var handler in Container.ResolveAll<Handles<T>>())
handler.Handle(args);
if (actions != null)
foreach (var action in actions)
if (action is Action<T>)
((Action<T>)action)(args);
}
}
How does the "Container" get set in this static class?
You will have to set it during application startup:
DomainEvents.Container = kernel;
what would be the Ninject syntax to resolve all the event handlers:
You can do it like this, for instance:
Container.Get<IEnumerable<Handles<T>>>())
Udi's static DomainEvents class is an implementation of the Ambient Context anti-pattern (see DI PP&P chapter 5.3). In this case I would rather use dependency injection to inject an IDomainEvents abstraction into code that needs it, instead of letting code depend on a static instance.
The problem however is that your domain objects will need a dependency on the IDomainEvents and constructor injection is (probably) not possible. The trick is to use method injection in that case.
In other words, use constructor injection to inject the IDomainEvents into command handlers or services (or what ever you call your business logic that uses the methods on your domain objects) and pass that dependency into the domain object when calling a method that needs it (method injection).

MEF - notify when plugins are loaded / unloaded

I have a simple asp mvc app which uses MEF, and there is a route which can be accessed by admins to refresh the directory catalog and compose parts, however one thing I am trying to find out how to do is notify some code when a plugin is loaded / unloaded.
The scenario is that when plugins are loaded they register the routes they need, however when they are unloaded I need them to unload their routes, as subsequent refreshes try to re-register the routes and it bombs.
Are there any events which I can hook into from the MEF objects?
The plugin container is something like:
[ImportMany(typeof(ISomePluginInterface))]
IEnumerable<ISomePluginInterface> Plugins {get; private set;}
Each ISomePluginInterface has something like:
public interface ISomePluginInterface
{
public void PluginLoaded();
public void PluginUnloaded();
}
This is similar in theory to this Stackoverflow question and this was my answer. In your case, you have a similar need, you want to fire an event when the plugin is started, and clean up when it is no longer needed.
Using the same concept, you can use the InterceptingCatalog to register routes, but I wouldn't make it an explicit part of the interface definition to do so, instead, you need to look at how your components fit together as a whole, e.g., if the operations for registering routes won't be used for all plugins, what is the purpose of them existing in the interface definition. You could break out the route registration into a separate interface, the IRouteRegistrar, and use intercepting strategies to automatically call the appropriate registration method when the plugin is used for the first time, e.g., I could break out the interface into:
public interface IPlugin
{
void SomeOperation();
}
public interface IRouteRegistrar : IDisposable
{
void RegisterRoutes();
}
The latter interface does the work of registering routes, and we use the Dispose pattern to ensure that it is cleaned up after it is finished with. Therefore, A sample plugin could resemble:
[Export(typeof(IPlugin))]
public class MyPlugin : IPlugin, IRouteRegistrar
{
public void SomeOperation() { }
public void RegisterRoutes()
{
// Register routes here...
}
protected virtual Dispose(bool disposing)
{
if (disposing)
{
// Unregister routes here...
}
}
void IDisposable.Dispose()
{
Dispose(true);
}
}
I only export as an IPlugin, but I ensure my plugin also implements the IRouteRegistrar. The way we use that, is with a strategy:
public class RouteRegistrarStrategy : IExportedValueInteceptor
{
public object Intercept(object value)
{
var registrar = value as IRouteRegistrar;
if (registrar != null)
registrar.RegisterRoutes();
return value;
}
}
Now, only if the plugin supports that interface will it register routes. This also enables you to apply the route registration interface to other plugins which could be used in a different way. You gain a bit more flexibility. To use that strategy in code, you need to add the MefContrib project to your app, and do a little more wire up:
var catalog = new DirectoryCatalog(".\bin");
var config = new InterceptionConfiguration().AddInterceptor(new RouteRegistrarStrategy());
var interceptingCatalog = new InterceptingCatalog(catalog, configuration);
var container = new CompositionContainer(interceptingCatalog);

Error "More than one matching bindings are available" when using Ninject.Web.Mvc 2.0 and ASP.NET MVC 1.0

Recently I've switched to Ninject 2.0 release and started getting the following error:
Error occured: Error activating SomeController
More than one matching bindings are available.
Activation path:
1) Request for SomeController
Suggestions:
1) Ensure that you have defined a binding for SomeController only once.
However, I'm unable to find certain reproduction path. Sometimes it occurs, sometimes it does not.
I'm using NinjectHttpApplication for automatic controllers injection. Controllers are defined in separate assembly:
public class App : NinjectHttpApplication
{
protected override IKernel CreateKernel()
{
INinjectModule[] modules = new INinjectModule[] {
new MiscModule(),
new ProvidersModule(),
new RepositoryModule(),
new ServiceModule()
};
return new StandardKernel(modules);
}
protected override void OnApplicationStarted()
{
RegisterRoutes(RouteTable.Routes);
RegisterAllControllersIn("Sample.Mvc");
base.OnApplicationStarted();
}
/* ............. */
}
Maybe someone is familiar with this error.
Any advice?
I finally figured this issue out recently. Apparently, the NinjectHttpApplication.RegisterAllControllersIn() function doesn't do all of the proper bindings needed. It binds your concrete controller implementations to IController requests. For example, if you have a controller class called SampleMvcController, which inherits from System.Web.Mvc.Controller. It would do the following named binding during application start:
kernel.Bind<IController>().To(SampleMvcController).InTransientScope().Named("SampleMvc");
But when debugging the NinjectControllerFactory, I find that request are being made for the Ninject Kernel to return an object for the class "SampleMvcController", not for a concrete implementation of IController, using the named binding of "SampleMvc".
Because of this, when the first web request that involves the SampleMvcController is made, it creates a binding of SampleMvcController to itself. This is not thread safe though. So if you have several web requests being made at once, the bindings can potentially happen more than once, and now you are left with this error for having multiple bindings for the SampleMvcController.
You can verify this by quickly refreshing an MVC URL, right after causing your web application to restart.
The fix:
The simplest way to fix this issue is to create a new NinjectModule for your controller bindings, and to load this module during application start. Within this module, you self bind each of your defined controllers, like so:
class ControllerModule : StandardModule {
public override Load() {
Bind<SampleMvcController>().ToSelf();
Bind<AnotherMvcController>().ToSelf();
}
}
But if you don't mind changing the Ninject source code, you can modify the RegisterAllControllersIn() function to self bind each controller it comes across.
I have been dealing with this problem for months. I tried so many options but was unable to come to a solution. I knew that it was a threading problem because it would only occur when there was a heavy load on my site. Just recently a bug was reported and fixed in the ninject source code that solves this problem.
Here is a reference to the issue. It was fixed in build 2.1.0.70 of the Ninject source. The key change was in KernelBase.cs by removing the line
context.Plan = planner.GetPlan(service);
and replacing it with
lock (planner)
{
context.Plan = planner.GetPlan(service);
}
To use this new build with MVC you will need to get the latest build of Ninject then get the latest build of ninject.web.mvc. Build ninject.web.mvc with the new Ninject build.
I have been using this new build for about a week with a heavy load and no problems. That is the longest it has gone without a problem so I would consider this to be a solution.
Are you sure you really are creating a single completely new Kernel from scratch in your OnApplicationStarted every time it's invoked ? If you're not and you're actually creating it once but potentially running the registration bit twice. Remember that you're not guaranteed to only ever have one App class instantiated ever within a given AppDomain.
My answer was a bit more obvious.
I had declared the binding for one of my controllers more than once during refactor of my code.
I added this to my global.ascx.cs file:
public void RegisterAllControllersInFix(Assembly assembly)
{
RegisterAllControllersInFix(assembly, GetControllerName);
}
public void RegisterAllControllersInFix(Assembly assembly, Func<Type, string> namingConvention)
{
foreach (Type type in assembly.GetExportedTypes().Where(IsController))
Kernel.Bind(type).ToSelf();
}
private static bool IsController(Type type)
{
return typeof(IController).IsAssignableFrom(type) && type.IsPublic && !type.IsAbstract && !type.IsInterface;
}
private static string GetControllerName(Type type)
{
string name = type.Name.ToLowerInvariant();
if (name.EndsWith("controller"))
name = name.Substring(0, name.IndexOf("controller"));
return name;
}
Then called it from my OnApplicationStarted() method as follows:
RegisterAllControllersIn(Assembly.GetExecutingAssembly());
RegisterAllControllersInFix(Assembly.GetExecutingAssembly());
Difficult to know whether this fixed it though because it's so intermittent.

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