Autofac instance management? - wcf

Question

Lets say I manually instantiate my objects like this:
var context = new MyDbContext();
_uow = new UnitOfWork(context);
_repository = new Repository<Account>(context, _uow);
Instead, I want to inject them and register them like so:
private readonly IUnitOfWorkAsync _uow;
private readonly IRepositoryAsync<Account> _repository;
public AccountService(IUnitOfWorkAsync uow, IRepositoryAsync<Account> repository)
{
_uow = uow;
_repository = repository;
}
Here is the registration.
builder.RegisterType<MyDbContext>().As<IDataContextAsync>().InstancePerDependency();
builder.RegisterType<UnitOfWork>().As<IUnitOfWorkAsync>();
builder.RegisterGeneric(typeof (Repository<>)).As(typeof (IRepositoryAsync<>));
builder.RegisterAssemblyTypes(typeof(AccountService).Assembly)
.Where(t => t.Name.EndsWith("Service"))
.As(t => t.GetInterfaces().FirstOrDefault(
i => i.Name == "I" + t.Name));
My service gets published to IIS and looks fine, but doesn't function correctly. For example, I go to insert a new Account and it doesn't save to the DB and doesn't error. It seems the injected UnitOfWork is not the same UnitOfWork used to instantiate the repository. I confirmed this with some code in the
constructor like so:
if(_uow.GetHashCode() != _repository.MyUow.GetHashCode())
throw new ArgumentException("Bad UOW");
If I inject the UnitOfWork and repository I ge the exception. If I manually instantiate my objects I do NOT get the exception. I've tried changing my registration to .InstancePerOwned() for the service and other various registration changes to no avail. How do I use Autofac registration to properly instantiate my repository BASED ON the UnitOfWork it already instantiated? I thought the default .InstancePerDependency() would suffice but doens't. Thanks.
Edit 1: I am using WCF and here is my CustomHostFactory. I don't see an option to specify .InstancePerRequest() like stated in the documentation. Also, interestingly, this line doesn't matter in the below code. Everything works exactly the same if I just take it out. AutofacServiceHostFactory.Container = container;
protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
{
Type contractType = GetContractType(serviceType);
var builder = new ContainerBuilder();
builder.RegisterType<MyDbContext>().As<IDataContextAsync>();
builder.RegisterType<UnitOfWork>().As<IUnitOfWorkAsync>();
builder.RegisterGeneric(typeof (Repository<>)).As(typeof (IRepositoryAsync<>));
builder.RegisterAssemblyTypes(typeof(AccountService).Assembly)
.Where(t => t.Name.EndsWith("Service"))
.As(t => t.GetInterfaces().FirstOrDefault(
i => i.Name == "I" + t.Name));
var container = builder.Build();
AutofacServiceHostFactory.Container = container;
var host = new CustomServiceHost(serviceType, baseAddresses);
host.AddDependencyInjectionBehavior(contractType, container);
return host;
}
private static Type GetContractType(Type serviceType)
{
return serviceType.GetInterfaces()
.FirstOrDefault(i => Attribute.IsDefined(i, typeof(ServiceContractAttribute), false));
}

Answer 1

InstancePerRequest is only available for WebForms and MVC integration packages.
Try using Autofac integration with WCF in svc.less mode properly, as described below.
From Autofac docs:
Svc-Less Services
If you want to use services without an .svc file, Autofac will work with that.
As shown above, register your service with the container.
var builder = new ContainerBuilder();
builder.RegisterType<Service1>();
AutofacHostFactory.Container = builder.Build();
To use svc-less services, add a factory entry under the serviceActivation element in the web.config file. This ensures that the AutofacServiceHostFactory is used to activate the service.
<serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true">
<serviceActivations>
<add factory="Autofac.Integration.Wcf.AutofacServiceHostFactory"
relativeAddress="~/Service1.svc"
service="TestService.Service1" />
</serviceActivations>
</serviceHostingEnvironment>

Answer 2

I needed to change the registrations like so:
var builder = new ContainerBuilder();
builder.RegisterType<MyDbContext>().As<IDataContextAsync>().InstancePerLifetimeScope();
builder.RegisterType<UnitOfWork>().As<IUnitOfWorkAsync>().InstancePerLifetimeScope();
builder.RegisterGeneric(typeof(Repository<>)).As(typeof(IRepositoryAsync<>)).InstancePerLifetimeScope();
builder.RegisterAssemblyTypes(typeof(AccountService).Assembly)
.Where(t => t.Name.EndsWith("Service"))
.As(t => t.GetInterfaces().FirstOrDefault(
i => i.Name == "I" + t.Name)).InstancePerLifetimeScope();
AutofacHostFactory.Container = builder.Build();
As well as setting each of my services to operate per call using the service behavior attribute below:
InstanceContextMode = InstanceContextMode.PerCall