Asp.Net Core Middleware service dependent on current user

Question

I would like to either change the service with a limited request, or install it at the user level of the middleware.

In particular, I want to be able to do something like the far-fetched example below in Startup.cs :

 public void ConfigureServices(IServiceCollection service) { service.AddScoped<IMyUserDependentService>((provider) => { return new MyService()); }); } public void Configure(...) { //other config removed app.Use(async (context, next) => { var myService = context.ApplicationServices.GetService<IMyUserDependentService>(); myService.SetUser(context.User.Identity.Name);//Name is Fred next.Invoke(); }); } 

Then in the controller, do the following:

 public class HomeController: Controller { public HomeController(IMyUserDependentService myService) { //myService.UserName should equal Fred } } 

The problem is that this does not work. myService.UserName is not Fred in the controller, this is null. I think the IOC container creates a new instance in the controller and does not use one set in the middleware.

If I changed the scope of the service to Transient, Fred will be remembered, but it will not help, because the service depends on who the current user is.

To repeat, I need to create / or edit a service that requires the current user (or other current request variables), but I cannot handle this.

Thanks in advance!

Answer 1

Have you tried using context.RequestServices ?

Answer 2

I just ran into a similar problem, I received an error message like InvalidOperationException: Cannot resolve scoped service 'IScopedService' from root provider. The exception was very poorly documented.

Here's how I solved it:

[Startup.cs]

 services.AddScoped<IAnyScopedService, AnyScopedService>(); services.AddSingleton<ISomeOtherSingletonService, SomeOtherSingletonService>(); 

[MyMiddleware.cs]

 public sealed class MyMiddleware { private readonly RequestDelegate _next; private readonly ISomeOtherSingletonService _Svc; public MyMiddleware( RequestDelegate next, ISomeOtherSingletonService svc) { _next = next; _Svc = svc; } public async Task Invoke(HttpContext context, IAnyScopedService scopedService) { // Some work with scoped service } } 

Indeed, Middleware is created only once, but is called many times. Consequently, the constructor accepts singleton instances where the invoke method can retrieve the entered scope parameters.

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