How to use Autofac to inject decorator of a class in one constructor and the class itself in another?

Question

I have an IoCConfig where in the RegisterDependencies method first all Services (same assembly as ServiceBase) are registered, except for one service and one class called LastActivityUpdator and a decorator of this class called AnonymousUserLastActivityUpdator which both implement ILastActivityUpdator.

The goals I want to accomplish is to have the decorator registered properly, which already works following this answer. And I also asked for a way to for one class (UserService) use the LastActivityUpdator and for another (AnonymousUserService) use the AnonymousUserLastActivityUpdator, which was answered here. To be complete (I don't think it is relevant to this problem), I am using a keyed service following this answer to decide which class is injected in other times.

Unfortunately, when I combine the ideas I always see an AnonymousUserLastActivityUpdator injected, also in the case of UserService where I want a LastActivityUpdator to be provided.

Below you'' find the IocConfig which uses both the idea to register the decorator and to provide specific classes with one type:

builder.RegisterAssemblyTypes(typeof(ServiceBase).Assembly)
    .Except<AnonymousUserService>()
    .Except<LastActivityUpdator>()
    .Except<AnonymousUserLastActivityUpdator>()
    .AsImplementedInterfaces()
    .InstancePerRequest();

builder.RegisterType<LastActivityUpdator>()
    .Named<ILastActivityUpdator>("lastActivityUpdator");
builder.RegisterType<AnonymousUserLastActivityUpdator>()
    .Named<ILastActivityUpdator>("anonymousUserLastActivityUpdator");

builder.RegisterDecorator<ILastActivityUpdator>(
    (c, inner) => c.ResolveNamed<ILastActivityUpdator>("anonymousUserLastActivityUpdator", 
        TypedParameter.From(inner)),
    fromKey: "lastActivityUpdator")
    .As<ILastActivityUpdator>();

builder.Register(c => new UserService(
    c.Resolve<OogstplannerUnitOfWork>(),
    c.Resolve<CookieProvider>(),
    c.Resolve<ILastActivityUpdator>()));
builder.Register(c => new AnonymousUserService(
    c.Resolve<OogstplannerUnitOfWork>(),
    c.Resolve<CookieProvider>(),
    c.Resolve<AnonymousUserLastActivityUpdator>()));

builder.RegisterType<AnonymousUserService>()
    .Keyed<IUserService>(AuthenticatedStatus.Anonymous)
    .InstancePerRequest();
builder.RegisterType<UserService>()
    .Keyed<IUserService>(AuthenticatedStatus.Authenticated)
    .InstancePerRequest();

Unfortunately this does not work. Both the AnonymousUserService and the UserService get an instance of the LastActivityUpdator, while I want AnonymousUserService to get an instance of the AnonymousUserService.

Does anyone know why my RegisterDependencies method does not provide the LastActivityUpdator to UserService and how I can accomplish this?

/edit

Using the answer of Cyril and some adjustments the registering works for the UserService, but once the user logs out and a AnonymousUserService is used I get the error:

Circular component dependency detected:
Services.AnonymousUserService ->
Services.AnonymousUserService ->
Services.AnonymousUserLastActivityUpdator ->
Services.AnonymousUserLastActivityUpdator -> System.Object ->
Services.AnonymousUserLastActivityUpdator

I adjusted the code somewhat of Cyril's answer (fixed some typos and switched the anonymous- and normal UserService) and I might have made a mistake, here it is:

builder.RegisterAssemblyTypes(typeof(ServiceBase).Assembly)
    .Except<AnonymousUserService>()
    .Except<LastActivityUpdator>()
    .Except<AnonymousUserLastActivityUpdator>()
    .AsImplementedInterfaces()
    .InstancePerRequest();

builder.RegisterType<LastActivityUpdator>()
    .Named<ILastActivityUpdator>("lastActivityUpdator");
builder.RegisterType<AnonymousUserLastActivityUpdator>()
    .Named<ILastActivityUpdator>("anonymousUserLastActivityUpdator");

builder.RegisterDecorator<ILastActivityUpdator>(
    (c, inner) => c.ResolveNamed<ILastActivityUpdator>("anonymousUserLastActivityUpdator", 
        TypedParameter.From(inner)),
    fromKey: "lastActivityUpdator")
    .As<ILastActivityUpdator>();

builder.RegisterType<UserService>()
    .Keyed<IUserService>(AuthenticatedStatus.Authenticated)
    .WithParameter(
        (p, c) => p.Name == "lastActivityUpdator", 
        (p, c) => c.ResolveNamed<ILastActivityUpdator>("lastActivityUpdator"))
    .InstancePerRequest();
builder.RegisterType<AnonymousUserService>()
    .Keyed<IUserService>(AuthenticatedStatus.Anonymous)
    .WithParameter(
        (p, c) => p.Name == "anonymousUserLastActivityUpdator", 
        (p, c) => c.ResolveNamed<ILastActivityUpdator>("anonymousUserLastActivityUpdator"))
    .InstancePerRequest();

var container = builder.Build();
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));

Cyril Durand · Accepted Answer · 2015-06-19T09:22:05.207

1

You have 2 kind of registrations for UserService and AnonymousUserService.

In the first solution you register AnonymousUserService by explicitly calling the constructor and by asking Autofac to resolve a AnonymousUserLastActivityUpdator but there is no registration for this service. Instead of resolving this type, you can resolve a named ILastActivityUpdator

builder.Register(c => new UserService(
    c.Resolve<OogstplannerUnitOfWork>(),
    c.Resolve<CookieProvider>(),
    c.Resolve<ILastActivityUpdator>()));
builder.Register(c => new AnonymousUserService(
    c.Resolve<OogstplannerUnitOfWork>(),
    c.Resolve<CookieProvider>(),
    c.ResolveNamed<ILastActivityUpdator>("anonymousUserLastActivityUpdator")));

The second registration is a Keyed but you don't specify that the AnonymousUserService should use a anonymousUserLastActivityUpdater you could do it by using the WithParameter method

builder.RegisterType<AnonymousUserService>()
       .Keyed<IUserService>(AuthenticatedStatus.Authenticated)
       .InstancePerRequest();
builder.RegisterType<UserService>()
       .Keyed<IUserService>(AuthenticatedStatus.Anonymous)
       .WithParameter(
         (pi, c) => pi.Name == "updater", 
         (pi, c) => ResolveNamed<ILastActivityUpdator>("anonymousUserLastActivityUpdator"))
       .InstancePerRequest();

You don't have to have both registration, the last one should be enough for your scenario.

edited Jun 19 '15 at 09:22

answered Jun 18 '15 at 23:12

Cyril Durand

15,834
5
54
62

Hi Cyril, thanks again for your answer. We are getting closer: the `UserService` gets the `LastActivityUpdator` injected, but once the `AnonymousUserService` is needed the error `Circular component dependency detected` pops up. I did make some adjustments to the answer you provided so I might have made a mistake in there. I've updated the answer (under the /edit) and would be very happy if you could take a look – user2609980 Jun 19 '15 at 08:54
1

You should not use the `WithParameter` method for both you registration. By doing so none of your registration used the decorator. For the error, do you need to register your types with the `RegisterAssemblyTypes` method ? I recommend you to register all your types manually and don't use assembly scanning and things like that. It will give you full control over your registration. Try to register your types manually and the error message may be more explicit – Cyril Durand Jun 19 '15 at 09:27
Thank you! I got it to work! Working registration registers the `UserService` as follows: `builder.Register(c => new UserService( c.Resolve(), c.Resolve(), c.ResolveNamed("lastActivityUpdator"))) .As() .InstancePerRequest();`. The problem was, I think, that resolving `ILastActivityUpdator` automatically gave an `AnonymousUserLastActivityUpdator`, this does not happen with ResolveNamed method.Thanks a lot again for your help! – user2609980 Jun 19 '15 at 10:52
Also, the `(p, c) => p.Name == "updater"` part cannot be `(p, c) => p.Name == "anonymousUserLastActivityUpdator"`, because when the same name is used as the named registration gives you a `DependencyResolutionException`. – user2609980 Jun 19 '15 at 10:57

How to use Autofac to inject decorator of a class in one constructor and the class itself in another?

1 Answers1

Linked