I'm using StructureMap for IoC and it works fine for regular controllers but I can't make it work with Areas. I have the following AccountController in Administration Area:
public class AccountController : Controller
{
private readonly IFormsAuthenticationService formsService;
private readonly IMembershipService membershipService;
public AccountController(IFormsAuthenticationService formsService, IMembershipService membershipService)
{
this.formsService = formsService;
this.membershipService = membershipService;
}
...
}
And here's the error:
System.InvalidOperationException: An error occurred when trying to create a controller of type 'Foo.Areas.Administration.Controllers.AccountController'. Make sure that the controller has a parameterless public constructor. ---> System.MissingMethodException: No parameterless constructor defined for this object.
Any help would be greatly appreciated!
EDIT
StructureMap couldn't resolve MembershipProvider.
Here's the solution:
For<MembershipProvider>().Use(Membership.Providers["AspNetSqlMembershipProvider"]);
I doubt that this is a problem with areas because I am using them happily. It is more likely a pure IOC issue. You get this error when one of the injected services cannot be resolved by your container, which has the consequence that the container cannot match a signature for the constructor and tries to fall back to the empty constructor, which doesn't exist, rightly.
So, my first instinct would be to make sure that the two injected services are available. It is possible that one of them did not get created properly; a common cause is that the Membership provider cannot connect to its database, or similar.
For diagnosing, in your global.asax, after the container has been created, see if you can manually resolve those two services. I don't know SM, but something like:
var s = container.Resolve<IMembershipService>();
Satisfy yourself that both those services can be resolved.
Related
all. I am getting started with NServiceBus and have a pretty good handle on the basics thanks to Pluralsight and the internet. I have an stock MVC 4 project and I have setup dependency injection for my controllers (thanks to this blog post).
Here is how I have my bus setup in Global.asax:
_bus = Configure.With()
.DefaultBuilder()
.ForMVC()
.Log4Net()
.XmlSerializer()
.MsmqTransport()
.UnicastBus()
.SendOnly();
I am assigning it to a local private variable because I need access to the bus in Global so I can do some stuff on Session_End. However, when I run, I get the following error:
The requested service 'System.Web.Mvc.IControllerFactory' has not been
registered. To avoid this exception, either register a component to
provide the service, check for service registration using
IsRegistered(), or use the ResolveOptional() method to resolve an
optional dependency.
According to my stack trace, the failure point is when Autofac tries to resolve the type. For the sake of sanity, I removed the private variable and used just the Configure statement, same thing. I also have Ninject wired up in this app because that is my IoC of choice. Thinking that it was interfering with Autofac in some way, I removed Ninject from the equation, still not working.
So my question is, what am I doing wrong? Am I missing something? This is my first time with NServiceBus, but from everything I've seen, this should just work. Any info would be super helpful. Thanks.
Have a look at our MVC4 sample (this is running against v4, the next major release):
https://github.com/NServiceBus/NServiceBus/tree/develop/Samples/Messaging.Msmq/MyWebClient
I found the solution from your code, John! Here was my issue. This is what I had in my Dependency Resolver Adapter:
public object GetService(Type serviceType)
{
_builder.Build(serviceType);
}
What I needed to do was what you did in your MVC4 example:
public object GetService(Type serviceType)
{
return (Configure.Instance.Configurer.HasComponent(serviceType)) ? _builder.Build(serviceType) : null;
}
Once I did that, it all sorted itself out. Thanks again for the help!
In normal ASP.MVC projects we configure the dependency resolver with Unity and the Unity.Mvc3 package from http://unitymvc3.codeplex.com/
We have this test service registered with a HierarchicalLifetimeManager
container.RegisterType<ITestService, TestService>(new HierarchicalLifetimeManager());
And we hook up the container with Mvc in Global.asax.cs:
System.Web.Mvc.DependencyResolver.SetResolver(new Unity.Mvc3.UnityDependencyResolver(container));
And we run this test controller:
public class TestController : Controller
{
private readonly ITestService _service;
public TestController(ITestService service)
{
this._service = service;
}
public ActionResult Test()
{
var locatedService = System.Web.Mvc.DependencyResolver.Current.GetService<ITestService>();
if (_service == locatedService)
return View("Success - Same Service");//This is always the result in an MVC controller
else
throw new Exception("Failure - Different Service Located");//This is never the result in an MVC controller
}
}
However, on this project we are adding a number of WebAPI controllers.
We have this configuration in global.asax.cs (using http://unitywebapi.codeplex.com/ for now. But I am open to suggestions):
System.Web.Http.GlobalConfiguration.Configuration.DependencyResolver = new Unity.WebApi.UnityDependencyResolver(container);
We have created an ApiTestController similar to TestController inheriting from ApiController rather than from Controller.
However, the ApiTestController fails its test. I understand that the System.Web.Mvc.DependencyResolver class and the System.Web.Mvc.DependencyResolver.Current property are specific to Mvc. But does WebAPI have an equivalent?
System.Web.Http.GlobalConfiguration.Configuration.DependencyResolver.GetService does not work because the System.Web.Http.GlobalConfiguration.Configuration.DependencyResolver instance is the parent container that I configured. It is not the child controller that was used to inject the ITestService into the constructor.
This user seems to have a similar problem: http://unitywebapi.codeplex.com/discussions/359413
But I feel that this probably has more to do with ASP.NET's WebAPI than it has to do with Unity.
Thanks
After looking over the source of http://unitymvc3.codeplex.com/ and http://unitywebapi.codeplex.com/ I created this class:
public class MyUnityDependencyResolver : Unity.Mvc3.UnityDependencyResolver, System.Web.Http.Dependencies.IDependencyResolver
{
public MyUnityDependencyResolver(IUnityContainer container)
: base(container)
{
}
public System.Web.Http.Dependencies.IDependencyScope BeginScope()
{
return this;
}
public void Dispose()
{
Unity.Mvc3.UnityDependencyResolver.DisposeOfChildContainer();
}
}
Configuration in gobal.asax.cs:
var myResolver = new MyUnityDependencyResolver(container);
System.Web.Mvc.DependencyResolver.SetResolver(myResolver);
System.Web.Http.GlobalConfiguration.Configuration.DependencyResolver = myResolver;
Unity.Mvc3.UnityDependencyResolver uses HttpContext.Current.Items to manage child containers. MyUnityDependencyResolver may not be the most "correct" implementation of System.Web.Http.Dependencies.IDependencyResolver, but it seems to work so far.
I will mark this as the answer in a couple days if no one else has any better answers.
Unfortunately, when you call the GlobalConfiguration.Configuration.DependencyResolver.GetService, it completely ignores any scope and resolves using the outer non-child container which is around for the lifetime of the application. This is an issue with Web Api and makes it impossible to use constructor injection for per-request dependencies outside of controllers. Confusingly this is completely different behaviour from MVC as you say.
What you can do is use the GetDependencyScope() extension method off HttpRequestMessage. Anything you resolve using this will be in per request scope when using HierarchicalLifetimeManager in conjunction with Unity.WebApi. The request is available from action filters and handlers so may be a viable workaround.
Obviously this is pure service location rather than dependency injection which is far from ideal but I have not found another way to access per-request dependencies outside of controllers.
See this post for more info.
The DependencyResolver is not the right seam for dependency injection in ASP.NET WebAPI.
Mark Seemann has two really good posts on DI with WebAPI.
Dependency Injection and Lifetime Management with ASP.NET Web API
Dependency Injection in ASP.NET Web API with Castle Windsor
If you want to do it right you should have a look at them.
I'm trying to get myself familiar with MVC3 and autofac but I've encountered small problem that I'm having trouble resolving.
I am using autofac integrated with MVC3 and all works well, pages are loading correctly, dependencies are being injected and that's cool. What's bugging me is how to use autofac's Container or MVC's DependencyResover in class library project.
I'm trying to create static class that will help me handle domain events. I simply want to be able to call the method with event parameter and everything should be handeled by this class. Here is code:
public static IContainer Container { get; set; }
public static void Raise<T>(T e) where T : IDomainEvent
{
foreach (var eventHandler in DomainEventManager.Container.Resolve<IEnumerable<EventHandlers.Handles<T>>>())
{
eventHandler.Handle(e);
}
}
As you can see it's pretty straightforward and everything would work great if it wasn't MVC approach. Some of my dependencies are registeres as InstancePerHttpRequest (NHibernate' session), while other are registered as InstancePerDependency or SingleInstance. Thus when I try to use container created in my UI project, I get exception that there is no httpRequest tag available.
How can i reuse the Container created in web project to get access to all of it's features, including InstancePerHttpRequest and httpRequest tag?
Or maybe there is other solution to my problem? I was thinking about using delegate function to obtain event handlers, but I cannot (can I?) create generic delegate that I would not need to initialize with concrete type at time of assignment.
Why I want to do this using static class is basically every entity and aggregate or service needs to be able to raise domain event. Injecting EventManager into every one of these would be troublesome and static class is exactly what would resolve all my problems.
If anyone could help me get my head around it I would be grateful.
Cheers, Pako
You shouldn't be referencing your container directly from your app code. This looks like the Service Locator anti-pattern. The correct action is to pass your objects the services they need to do their jobs, usually done through constructor parameters. BUT... if you are going to insist on depending on a global static, then at least model EventManager as a singleton, such that usage would look like:
EventManager.Current.Raise<SomeEvent>(someObject);
and then you can set EventManager.Current equal to a properly constructed instance when your app is initialized.
I would like to write and read data to Session even if my class not inherited from controller or helper. Something like this:
public class User
{
public void CreateSession()
{
Session["key"]=data;
}
public void ReadSession()
{
data=(string)Session["key"];
}
}
Important thing - I need to get instance of User class in some actions
and views. Am I be able to inherit User class from controller or
helper. Because I've already try that, but I got some errors.
How can I achive this?
Thanks in advance.
HttpContext.Session will work, it's a static available anywhere to an assembly that references System.Web.
If your code is in your main website assembly, this should work well. If it's not, you'll have to create a dependency on System.Web which you may or may not want to do.
You should do these kind of things in your controller.
You can access HttpContext directly, but that's not "the ASP.NET MVC way", and you loose some of the advantages of using MVC in the first place. Like making testing harder, and directly coupling your application to HttpContext...
Also, if it's a new session, or Session["key"] is not set for some reason, data=(string)Session["key"]; would throw a null reference exception.
I'm trying to setup an 'Authorization' Filter on an Action, creating my own ActionFilterAttribute where I do a database lookup to determine if a user has access to a certain resource.
On my class inheriting from ActionFilterAttribute, I have created an Injected(Ninject) property to hold the service that I am using for the database access. I have a parameterless constructor so that I can use this as an attribute on my actions. In the 'OnActionExecuting' Method, I am able to gain access to the Injected property (it's not null), but the base DBCotext that it is using is closed.
This working fine, up until the RTM of MVC3, where the Release Notes stated:
Breaking Changes:
In previous versions of ASP.NET MVC, action filters are create per
request except in a few cases. This
behavior was never a guaranteed
behavior but merely an implementation
detail and the contract for filters
was to consider them stateless. In
ASP.NET MVC 3, filters are cached more
aggressively. Therefore, any custom
action filters which improperly store
instance state might be broken.
The first time I use this filter, it works as expected, but if I refresh the page or another user access this filter, I get the error:
The operation cannot be completed
because the DbContext has been
disposed.
which is what I guess I should expect given the breaking changes notes.
My question is this, what would be the preferred/recommended way of accomplishing what I need to do? Should this be in an ActionFilterAttribute, or should this 'authorization' be done somewhere else?
I'd do authentication in Application_AuthenticateRequest and authorization in your attribute using Thread.CurrentPrincipal, but your method should work too. You just need to count with fact that DbContext will be different for each request but your attribute won't. Something like this should do the trick (I'm assuming you are using DependencyResolver):
public class MyMightyAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
var context = (DbContext)DependencyResolver.Current.GetService(typeof(DbContext))
// authenticate, authorize, whatever
base.OnActionExecuting(filterContext);
}
}
I have been battling with this for a while and finally solved my problem. So here is my solution in the hope it may help someone else.
The setup:
1. I have an MVC3 project, a custom action filter that accesses the db using EF5 via a business service.
2. I use Unity and unity.MVC to resolve my dependencies on a per request basis.
3. I use property injection into my custom Action filter, as it has a parameterless constructor.
The result.
Dependency injection works correctly for all the services used by actions, my EF DbContext is correctly disposed of at the end of each request.
The Problem
Although my property dependency is resolved in my custom action filter, it contains a stale instance of my DbContext (e.g. it seems to have been cached from the previous request)
As mentioned in previous posts, MVC3 is more aggressive with filter caching and the state of a filter cannot be relied on. So the suggestion was to resolve the dependency in the OnActionExecuting method. So I removed my injected property and did just that called resolve on my unity container. However I still got a stale version of the DbContext. Any changes in the DB were correctly queried in my main actions, but the custom action filter didn’t pick them up.
The solution.
Unity.MVC Manages per-request lifetime by using child containers and disposing these at the end of each request. By resolving my dependency’s in the action filter from my unity container I was resolving from the parent container which is not disposed of on each request.
So rather than
IoC.Instance.CurrentContainer.Resolve<IService>();
I used this to obtain an instance of the child container rather than parent.
var childContainer = HttpContext.Current.Items["perRequestContainer"] as IUnityContainer;
var service = childContainer.Resolve<IServcie>();
I'm sure there must be a clean way to achive the same result, so please add suggestions.
Ok slight refinement to allow my unit test to inject a mock of the service.
1. remove the dependency resolve from the the OnActionexecuting and add two constructors.
public MyCustomActionfilter() : this(((IUnityContainer)HttpContext.Current.Items["perRequestContainer"].Resolve<IService>())
and
public MyCustomActionfilter(IService service)
{
this.service = service;
}
Now the constructor resolves your service and stores it as a private readonly. This can now be consumed in your OnActionExecutng function. Unit tests can now call the second constructor and inject a mock.