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Constructor injection of InstancePerRequest to service resolves new instance

I register a service FooRequest as InstancePerRequest in ASP.NET MVC & OWIN:
builder.RegisterType<FooRequest>().AsSelf().InstancePerRequest();
After that I resolve FooRequest in two locations. First is global.asax Application_BeginRequest():
protected void Application_BeginRequest(object sender, EventArgs e)
{
var fooRequest = DependencyResolver.Current.GetService<FooRequest>();
}
A second time in another services constructer. The other service has InstancePerLifetimeScope:
public class FooService
{
public FooService(FooRequest fooRequest)
{
...
}
}
My problem is that those two resolves in different instances of FooService and the one used in constructor injection of service does not call Dispose[Async] on the end of the request.
What am I doing wrong?
Btw. using DependencyResolver.Current.GetService<FooRequest>() outside the constructor does resolve the proper instance of FooRequest in FooService.
Additional requested information
OWIN & Container configuration:
[assembly: OwinStartup(typeof(Project.Web.Startup))]
namespace Project.Web
{
public partial class Startup
{
public void Configuration(IAppBuilder app)
{
var builder = new ContainerBuilder();
// REGISTER CONTROLLERS SO DEPENDENCIES ARE CONSTRUCTOR INJECTED
builder.RegisterControllers(typeof(MvcApplication).Assembly);
builder.RegisterApiControllers(typeof(MvcApplication).Assembly);
// REGISTER DEPENDENCIES
builder.RegisterModule(new ProjectWebModule());
builder.Register(c => new IdentityFactoryOptions<ApplicationUserManager> { DataProtectionProvider = app.GetDataProtectionProvider() });
// REGISTER FILTERS SO DEPENDENCIES ARE PROPERTY INJECTED
builder.RegisterFilterProvider();
// BUILD THE CONTAINER
var container = builder.Build();
// REPLACE THE MVC DEPENDENCY RESOLVER WITH AUTOFAC
DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
// REPLACE THE WEBAPI DEPENDENCY RESOLVER WITH AUTOFAC
GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver(container);
// REGISTER WITH OWIN
app.UseAutofacMiddleware(container);
app.UseAutofacMvc();
app.Use((context, next) =>
{
var httpContext = context.Get<HttpContextBase>(typeof(HttpContextBase).FullName);
httpContext.SetSessionStateBehavior(SessionStateBehavior.Required);
return next();
});
// STANDARD MVC SETUP
RouteConfig.RegisterRoutes(RouteTable.Routes);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); // immer nach RouteConfig.RegisterRoutes ausführen!
BundleConfig.RegisterBundles(BundleTable.Bundles);
// PLACE ConfigureAuth AFTER RegisterGlobalFilters
ConfigureAuth(app);
}
}
}
ProjectWebModule
namespace Project.Web.Autofac
{
public class ProjectWebModule : Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterType<FooRequest>().AsSelf().InstancePerRequest();
builder.RegisterType<FooService>().AsSelf().InstancePerLifetimeScope();
builder.Register(c => HttpContext.Current.GetOwinContext().Authentication).As<IAuthenticationManager>();
builder.Register(c =>
//register FakeHttpContext when HttpContext is not available
HttpContext.Current != null
? new HttpContextWrapper(HttpContext.Current) as HttpContextBase
: new FakeHttpContext("~/") as HttpContextBase)
.As<HttpContextBase>()
.InstancePerLifetimeScope()
.OnActivated(e =>
{
Toolbox.HttpContext = e.Instance;
});
builder.Register(c => c.Resolve<HttpContextBase>().Request)
.As<HttpRequestBase>()
.InstancePerLifetimeScope();
builder.Register(c => c.Resolve<HttpContextBase>().Response)
.As<HttpResponseBase>()
.InstancePerLifetimeScope();
builder.Register(c => c.Resolve<HttpContextBase>().Server)
.As<HttpServerUtilityBase>()
.InstancePerLifetimeScope();
builder.Register(c => c.Resolve<HttpContextBase>().Session)
.As<HttpSessionStateBase>()
.InstancePerLifetimeScope();
base.Load(builder);
}
}
}

I mention in the comments on the question that there's not enough info here to really tell, but here's my guess: you have a race condition.
As you know from the Autofac.Mvc.Owin README and the MVC/OWIN integration docs, ASP.NET MVC doesn't actually fully run in the OWIN pipeline. Trying to make the two work creates some weird issues that aren't of Autofac's creation. For example (again, from the Autofac docs):
Minor gotcha: MVC doesn’t run 100% in the OWIN pipeline. It still needs HttpContext.Current and some other non-OWIN things. At application startup, when MVC registers routes, it instantiates an IControllerFactory that ends up creating two request lifetime scopes. It only happens during app startup at route registration time, not once requests start getting handled, but it’s something to be aware of. This is an artifact of the two pipelines being mangled together. We looked into ways to try working around it but were unable to do so in a clean fashion.
But that also means there's a sort of order around when Application_BeginRequest handlers run that could cause oddness like what you're seeing. For example, the Autofac OWIN MVC integration tries to set up a request lifetime (if it's not already set up) when you put app.UseAutofacMvc() in the pipeline, but the ASP.NET MVC framework also tries to set up a request lifetime internally (using DependencyResolver.Current), so those things have to work together. It's not entirely impossible that your Application_BeginRequest handler is resolving from a different lifetime scope than what the MVC framework is trying to set up as the request lifetime, for example if the MVC framework hasn't had a chance to set it up before you've tried resolving from it.
I would recommend if you're trying to use OWIN with MVC, give in to OWIN and actually use OWIN middleware in the pipeline rather than event handlers in MVC. It'll remove the race condition for Application_BeginRequest and give you greater control over the order of operations. It'll also get you closer to where ASP.NET Core is so if/when it's time to migrate your application you won't have to deal with the event handlers that aren't there anymore.
Of course, again, this is totally a guess based on what I could gather from the question. Hopefully it helps.
Edit after new info was added to question: I think my guess is still correct, but it also looks like you're not setting up OWIN right for WebAPI, which could contribute to the problem. You shouldn't be using GlobalConfiguration. Also, again, MVC doesn't really run in OWIN, so you may see weirdness trying to get two app types (MVC, WebAPI) with two different pipelines to mash together. It's why they unified it in ASP.NET Core.

Autofac scope issues

I am trying to get autofac to work, but having issues with my unitofwork / user manager classes.
Initially I set my unit of work up as a per request instance like this:
builder.RegisterType<UnitOfWork<DatabaseContext>>().As<IUnitOfWork>().InstancePerRequest();
But in my StartupConfig.cs I was trying to set up oAuth like this:
private static OAuthAuthorizationServerOptions ConfigureOAuthTokenGeneration(IAppBuilder app, ILifetimeScope scope)
{
var t = scope.Resolve<IPasswordHasher>();
// Get our providers
var authProvider = scope.Resolve<OAuthProvider>();
var refreshTokenProvider = scope.Resolve<IAuthenticationTokenProvider>();
// Create our OAuth options
return new OAuthAuthorizationServerOptions()
{
AllowInsecureHttp = true, // TODO: Remove this line
TokenEndpointPath = new PathString("/oauth/access_token"),
AccessTokenExpireTimeSpan = TimeSpan.FromDays(1),
AccessTokenFormat = new Business.Authentication.JwtFormat("http://localhost:62668"),
Provider = authProvider,
RefreshTokenProvider = refreshTokenProvider
};
}
The scope is obtained by this:
var scope = config.DependencyResolver.GetRootLifetimeScope();
Because of this, I could not use InstancePerRequest for the UnitOfWork, instead I changed it to this:
builder.RegisterType<UnitOfWork<DatabaseContext>>().As<IUnitOfWork>().InstancePerLifetimeScope();
Now the application actually runs, but I get a new error with my UserProvider, it is instantiated like this:
builder.RegisterType<UserProvider>().As<IUserProvider>().InstancePerRequest();
But if I run that, I get this error:
No scope with a tag matching 'AutofacWebRequest' is visible from the scope in which the instance was requested.
If you see this during execution of a web application, it generally indicates that a component registered as per-HTTP request is being requested by a SingleInstance() component (or a similar scenario). Under the web integration always request dependencies from the dependency resolver or the request lifetime scope, never from the container itself.
This is actually being invoked by the line:
var authProvider = scope.Resolve<OAuthProvider>();
which is in my StartupConfig.cs. The OAuthProvider does need the UserProvider, the signature looks like this:
public OAuthProvider(IAdvancedEncryptionStandardProvider helper, IUserProvider userProvider)
{
this._helper = helper;
this._userProvider = userProvider;
}
So because this is not in the "request", I changed the UserProvider to be resolved like this:
builder.RegisterType<UserProvider>().As<IUserProvider>().InstancePerLifetimeScope();
which matches the UnitOfWork now, the project will load. But if I have an interface that tries to do 2 things (get the current user and list all users) it creates 2 requests, both creating a new instance of the UserController:
public UsersController(IUserProvider provider)
{
this._provider = provider;
}
which in turn tries to create 2 instances of the UserProvider. This throws an error:
The context cannot be used while the model is being created. This exception may be thrown if the context is used inside the OnModelCreating method or if the same context instance is accessed by multiple threads concurrently. Note that instance members of DbContext and related classes are not guaranteed to be thread safe.
So, I guess I need to know how I can resolve this.
It's like I need 2 scopes, one for the start of the application and then another for everything else.
Can anyone help me with this?

The issue
Since, at the time of the OWIN middleware registration, you need to provide an instance of OAuthAuthorizationServerOptions, there's no way to resolve the Provider and RefreshTokenProvider properties per HTTP request.
What we need is a way to create the OAuthAuthorizationServerOptions per HTTP request. By extension, the same concept would apply to the OAuthAuthorizationServerMiddleware.
A possible solution
That's exactly what AutofacMiddleware<T> does; It wraps an OWIN middleware by resolving it during the HTTP request from the lifetime scope stored in the OWIN context, then executes it. This means that we can now instantiate a new OAuthAuthorizationServerMiddleware for each HTTP request.
As explained in the documentation, when you use app.UseAutofacMiddleware(container) in your Startup class, Autofac does 2 things:
it hooks itself in the OWIN pipeline to create a nested lifetime scope for each HTTP request
it wraps all the OwinMiddleware services registered in the container with AutofacMiddleware and adds them to the OWIN pipeline
The solution is then to register OAuthAuthorizationServerMiddleware and all its dependencies in the Autofac container, and it will be automatically resolved for each request and executed.
OAuthAuthorizationServerMiddleware has 3 dependencies:
The next OWIN middleware in the pipeline, which AutofacMiddleware takes care of as it provides it to the Resolve method - TypedParameter.From(this.Next)
An instance of IAppBuilder
The OAuthAuthorizationServerOptions instance
We have to register the last two dependencies plus the middleware itself in the container. Let's have a look at what this could look like:
Disclaimer: I didn't try the code below
// Here go all the registrations associated with the `Provider`
// and `RefreshTokenProvider` properties with the appropriate lifetimes
builder
.RegisterInstance(app)
.As<IAppBuilder>();
builder
.Register(x => new OAuthAuthorizationServerOptions
{
AllowInsecureHttp = true, // TODO: Remove this line
TokenEndpointPath = new PathString("/oauth/access_token"),
AccessTokenExpireTimeSpan = TimeSpan.FromDays(1),
AccessTokenFormat = new Business.Authentication.JwtFormat("http://localhost:62668"),
Provider = x.Resolve<OAuthProvider>(),
RefreshTokenProvider = x.Resolve<IAuthenticationTokenProvider>()
})
.AsSelf()
// InstancePerDependency is same as InstancePerLifetimeScope
// in this case since the middleware will get resolved exactly one
// time per HTTP request anyway
.InstancePerDependency();
builder.RegisterType<OAuthAuthorizationServerMiddleware>();
Controlling the middleware order
While this could work, it's possible that it doesn't suit your needs since the OAuth middleware will be registered in the OWIN pipeline where you call app.UseAutofacMiddleware(container).
If you want more control over middleware order, you can separate the Autofac lifetime scope creation from the middleware registration in the OWIN pipeline:
Disclaimer: I didn't try the code below
// creates the per HTTP request lifetime scope
app.UseAutofacLifetimeScopeInjector(container);
// "usual" OWIN middlewares registrations
app.UseFoo();
// now use one from the container
app.UseMiddlewareFromContainer<OAuthAuthorizationServerMiddleware>();
// other "usual" OWIN middlewares registrations
app.UseBar();

PerHttpRequestLifeTimeManager for Unity with Web API and OWIN

I have a web service which is build using web API 5.23 with OWIN. I'm using Unity as IOC container.
This web service is consumed by a windows service that fires http requests every 2 seconds.
When the windows service starts, the following exception is thrown on the web service:
System.NotSupportedException occurred
HResult=-2146233067
Message=A second operation started on this context before a previous asynchronous operation completed. Use 'await' to ensure that any asynchronous operations have completed before calling another method on this context. Any instance members are not guaranteed to be thread safe.
From what I can tell two threads are trying to use the same instance of a DbContext, so creating a new DbContext on each request should solve my problem.
Looking at the LifeTimeManagers that Unity provides, it would seem that TransientLifetimeManager is the way to go since
TransientLifetimeManager. For this lifetime manager Unity creates and returns a new instance of the requested type for each call to the Resolve or ResolveAll method. This lifetime manager is used by default for all types registered using the RegisterType, method unless you specify a different lifetime manager.
For some reason this does not work and I am still getting the same exception.
After some more searching, I found PerRequestLifetimeManager . But I can't use it since I don't want to have a dependency of MVC. When I checked the way it is implemented I noticed that it dependes on IHttpModule. I am not sure if I can use this since I am using OWIN middleware to host my web service.
How can I implement a PerRequestLifetimeManager for Web API with OWIN?
Details just in case I am doing something wrong:
public static class MiddlewareContainer
{
public static void Register(IUnityContainer container)
{
container.RegisterType<DbContext, LicenceDbContext>(new TransientLifetimeManager());
container.RegisterType<IdentityDbContext<IdentityUser>, LicenceDbContext>(new TransientLifetimeManager());
container.RegisterType<IOAuthAuthorizationServerProvider, LicenceAuthorizationProvider>(new TransientLifetimeManager(),
new Interceptor<InterfaceInterceptor>(),
new InterceptionBehavior<AuthorizationProviderLoggingInterceptionBehavior>());
container.RegisterType<IDeploymentAuthRepository, DeploymentAuthRepository>(new TransientLifetimeManager());
container.RegisterType(typeof (UserManager<>), typeof (UserManager<>) ,new TransientLifetimeManager());
container.RegisterType(typeof (IUserStore<>), typeof (UserStore<>), new TransientLifetimeManager());
container.RegisterType(typeof(IRepository<>), typeof(Repository<>));
container.RegisterType<IHttpActionResultProvider, HttpActionResultProvider>();
container.RegisterType<IClaimsIdentityFactory, ClaimsIdentityFactory>();
container.RegisterType<LoggingInterceptionBehavior, AuthorizationProviderLoggingInterceptionBehavior>();
container.RegisterType<ILogger, Logger>();
container.RegisterType<IIdentityProvider, IdentityProvider>();
container.RegisterType<IIdentityProviderFactory, IdentityProviderFactory>();
container.RegisterType<ILogger, Logger>();
container.RegisterType(typeof (IRepository<>), typeof (Repository<>));
container.RegisterType<IRepository<UserActivity>, UserActivityRepository>();
container.RegisterType<IRepository<Licence>, LicenceRepository>();
container.RegisterType<IJsonConverter, JsonConverter>();
container.RegisterType<IEqualityComparer<Message>, MessageComparer>();
container.RegisterType<System.Web.Http.ExceptionHandling.ExceptionLogger, GenericExceptionLogger>();
}
}
public class Startup
{
public void Configuration(IAppBuilder app)
{
HttpConfiguration config = new HttpConfiguration();
var container = new UnityContainer();
container.AddNewExtension<Interception>();
MiddlewareContainer.Register(container);
config.DependencyResolver = new UnityResolver(container);
ConfigureFilters(config, container);
ConfigureOAuth(app,container);
WebApiConfig.Register(config);
app.UseWebApi(config);
app.UseCors(Microsoft.Owin.Cors.CorsOptions.AllowAll);
}

Found the issue. It had nothing to do with Unity. In the Startup class I was calling
ConfigureOAuth(app,container);
From the code posted in the question, there is no way of knowing this could be an issue. (apologies for that).
Here is the content of the method.
public void ConfigureOAuth(IAppBuilder app, UnityContainer container)
{
OAuthAuthorizationServerOptions oAuthServerOptions = new OAuthAuthorizationServerOptions()
{
AllowInsecureHttp = true,
TokenEndpointPath = new PathString("/token"),
AccessTokenExpireTimeSpan = TimeSpan.FromHours(1),
Provider = container.Resolve<IOAuthAuthorizationServerProvider>()
};
app.UseOAuthAuthorizationServer(oAuthServerOptions);
app.UseOAuthBearerAuthentication(new OAuthBearerAuthenticationOptions());
}
When instantiating OAuthAuthorizationServerOptions, I have to also instantiate a Provider.
That provider is part of the OWIN pipeline and is instantiated only once, when the server starts. Each incoming request will hit that provider causing the above error. (Multiple requests are trying to use the same DbContext).
Making IOAuthAuthorizationServerProvider thread safe solved the issue, but that is not the ideal case.
The ideal solution would be to specify a providerFactory and that factory would create a new provider for each request.

Injecting a dependency into OWIN Middleware and per web-request with Simple Injector

I am trying to work out how to best inject all of my dependencies into the custom OWIN Middleware I have written for a Web API Application. A simple example would be the DbContext I am using. I have some middleware that needs to potentially query based on the request. The issue I have is that I want my DbContext to otherwise have a WebApiRequestLifestyle scope. My DbContext is registered as such:
container.Register<MobileDbContext>(Lifestyle.Scoped);
Obviously, this does not work:
container.Options.DefaultScopedLifestyle = new WebApiRequestLifestyle();
Because I need the MobileDbContext in my Middleware using something like:
app.CreatePerOwinContext(() =>
{
return container.GetInstance<MobileDbContext>();
};
I tried a hybrid lifestyle, but that also didn't work because I don't think the Middleware is technically something that can fall under a "scoped" lifestyle. It is probably closer to a singleton, I would think.
Is there a better way to design my app to avoid this problem or address it with some sort of custom scoped lifestyle?

The documentation shows an example of how to wrap an OWIN request in a scope:
public void Configuration(IAppBuilder app) {
app.Use(async (context, next) => {
using (AsyncScopedLifedtyle.BeginScope (container)) {
await next();
}
});
}
What this does is wrapping an OWIN request in an execution context scope. All you have to do now is make the execution contest scope the default scoped lifestyle as follows:
container.Options.DefaultScopedLifestyle = new AsyncScopedLifestyle();

Dependency injecting UserStore in OWIN startup using Ninject OWIN middleware

I am having problems creating a custom UserStore using dependency injection when creating an ApplicationUserManager using the OWIN request pipeline.
Background
I am trying to migrate the user functionality in our web application from using the SimpleMembership to the new ASP.NET Identity. When starting a new MVC 5 project, the default implementation of the single page application uses ASP.Identity, using Entity Framework to implement the UserStore functionality.
In my case, we are already using NHibernate as the ORM, and using ninject to implement the unit of work pattern so that we had one NHibernate session per request, and I wanted to make the ASP.Identity work with our existing framework.
To this end, I created a custom UserStore, which could be created by injecting the relevant repositories/nhibernate session, etc. This could then be injected into the Controller's constructor using Ninject, rather than using the default implementation's GetOwinContext functionality.
In order to do this, I had commented out the following line in the ConfigureAuth(IAppBuilder app) method of the Startup, which by default creates the UserManager class:
// app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
Instead, I used the NinjectWebCommon created when installing the Ninject.Web.Common.Webhost nuget package to create the relevant bindings.
This implementation worked fine with some of the UserManager operations, but with some operations, such as ResetPasswordAsync, it fails because the default ApplicationUserManager implementation is not called, and so the UserTokenProvider in the UserManager class is never set:
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
var manager = new ApplicationUserManager(new UserStore<ApplicationUser>(context.Get<ApplicationDbContext>()));
// Configure validation logic for usernames
manager.UserValidator = new UserValidator<ApplicationUser>(manager)
{
AllowOnlyAlphanumericUserNames = false,
RequireUniqueEmail = true
};
// Configure validation logic for passwords
manager.PasswordValidator = new PasswordValidator
{
RequiredLength = 6,
RequireNonLetterOrDigit = true,
RequireDigit = true,
RequireLowercase = true,
RequireUppercase = true,
};
// Register two factor authentication providers. This application uses Phone and Emails as a step of receiving a code for verifying the user
// You can write your own provider and plug in here.
manager.RegisterTwoFactorProvider("PhoneCode", new PhoneNumberTokenProvider<ApplicationUser>
{
MessageFormat = "Your security code is: {0}"
});
manager.RegisterTwoFactorProvider("EmailCode", new EmailTokenProvider<ApplicationUser>
{
Subject = "Security Code",
BodyFormat = "Your security code is: {0}"
});
manager.EmailService = new EmailService();
manager.SmsService = new SmsService();
var dataProtectionProvider = options.DataProtectionProvider;
if (dataProtectionProvider != null)
{
manager.UserTokenProvider = new DataProtectorTokenProvider<ApplicationUser>(dataProtectionProvider.Create("ASP.NET Identity"));
}
return manager;
}
Therefore, the UserTokenProvider is not set.
Problem
I want to use the OWIN pipeline, because Visual Studio's default implementation of the ApplicationUserManager class injects the IDataProtectionProvider in its Create callback method. However, I also want to create my UserStore using dependency Injection, and I do not know how to create a UserStore within this method using dependency injection.
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
// WANT TO CREATE THE USER STORE USING NINJECT DEPENDENCY INJECTION HERE
// var userStore = ...
var manager = new ApplicationUserManager(userStore);
}
I have tried to get around this limitation by using the Ninject.Web.Common.OwinHost nuget package and creating the kernel within the Startup class.
public void ConfigureAuth(IAppBuilder app)
{
// Setup
app.UseNinjectMiddleware(CreateKernel);
}
However, the Ninject.Web.Common.OwinHost does not expose its Kernel, so I am unable to use service location pattern to inject the values into my custom UserStore in the Create callback.
I have also tried to create a singleton Kernel, and register this using app.CreatePerOwinContext(CreateKernel) with the relevant delegate, so I could later access the Kernel, but when I call context.Get() it just returns null.
Question
How can I register a callback function with CreatePerOwinContext to create a custom UserManager which uses a custom UserStore, and then use Ninject to create the custom UserStore using dependency injection in the Create callback, so that I also have access to the IdentityFactoryOptions which Owin uses to inject the user token provider?

For info:
It is possible to register the kernel as a singleton so that the same kernel can be used by the ninject middleware and also registered within the owin context.
public static StandardKernel CreateKernel()
{
if (_kernel == null)
{
_kernel = new StandardKernel();
_kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>();
_kernel.Load(Assembly.GetExecutingAssembly(), Assembly.Load("Super.CompositionRoot"));
}
return _kernel;
}
The callback function app.CreatePerOwinContext(ApplicationUserManager.Create), will call the ApplicationUserManager.Create rather than register it to be called at a later point during the setup. Therefore, the CreateKernel function needs to be registered before the ApplicationUserManager's Create callback or you will get a null reference exception if you try to get the kernel from the owin context within that method.
public void ConfigureAuth(IAppBuilder app)
{
app.CreatePerOwinContext(CreateKernel);
app.UseNinjectMiddleware(CreateKernel);
app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
}
This will allow you to access the kernel to create a custom UserStore within the ApplicationUserManager's Create callback:
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
var kernel = context.Get<StandardKernel>();
var userStore = kernel.Get<IUserStore<User, int>>();
var manager = new ApplicationUserManager(userStore);
//...
}
I know that in general dependency injection should be favoured over service location, but in this context I couldn't see a way around it - unless anybody has any better suggestions?
This will allow you to use Ninject to implement the unit of work patter leveraging Ninject's InRequestScope().OnDeactivation functionality. I'm aware that the UserManager class has a per request lifetime, but didn't know the most the most appropriate way to commit any outstanding transactions on request finish.

Note This was for WebApi (using System.Web.Http)
Okay so I kind of cheated by using stuff from System.Web which is the namespace we're suppose to be weening ourselves off of, but while its still used, why not.
Firstly, I use some helpers from this SO question:
Configuring Ninject with Asp.Net MVC & Web Api
Within which, the resolver is registered with System.Web's global configuration. Thus, I just go grab it when I need it:
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
var repository = System.Web.Http.GlobalConfiguration.Configuration.DependencyResolver
.GetService(typeof(Data.Repositories.UserRepository)) as Data.Repositories.UserRepository;
var manager = new ApplicationUserManager(repository);
...
Note: I use the term Repository over Store since it matches the well-known pattern, more understandable to most people.
And the Startup.Auth looks like this, I basically move the Ninject init into here so its done in time:
public void ConfigureAuth(IAppBuilder app)
{
// Dependency Injection
Evoq.AppName.Configuration.Ninject.NinjectHttpContainer.RegisterAssembly();
// Configure the db context and user manager to use a single instance per request
app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
...
I did also use a method similar to the OP where I 'attached' a callback to get the IKernel but while this keeps it all OWINy, the problem with this approach is that you have to call owinContextThing.Get<IKernel>() which means referencing Ninject deeper in my code.
There were ways around it, but it started getting more complex than my solution above.
Additional Note
This is the Identity Framework code that registers the callback. Note the call to app.GetDataProtectionProvider which is essentially the thing we originally needed to make a UserTokenProvider.
/// <summary>
/// Registers a callback that will be invoked to create an instance of type T that will be stored in the OwinContext which can fetched via context.Get
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="app"></param>
/// <param name="createCallback"></param>
/// <returns></returns>
public static IAppBuilder CreatePerOwinContext<T>(this IAppBuilder app, Func<IdentityFactoryOptions<T>, IOwinContext, T> createCallback) where T : class,IDisposable {
if (app == null) {
throw new ArgumentNullException("app");
}
if (createCallback == null) {
throw new ArgumentNullException("createCallback");
}
app.Use(typeof(IdentityFactoryMiddleware<T, IdentityFactoryOptions<T>>),
new IdentityFactoryOptions<T>() {
DataProtectionProvider = app.GetDataProtectionProvider(),
Provider = new IdentityFactoryProvider<T>() {
OnCreate = createCallback
}
});
return app;
}
I've looked and looked and reflected the libs and cannot find that method! If I knew how that worked, potentially we could find another way to create a token, i.e. wouldn't need the options instance.