Allow scoped sub-requests

[petronellius]

I would expect every sub-request runs in its own scope. So sub-request gets new instance for scoped services.

As a workaround I tried to define custom BatchMiddlewareEvents class and it seems to work.

public class CustomBatchMiddlewareEvents : BatchMiddlewareEvents
{
	public override Task BatchRequestExecutingAsync(
		BatchRequestExecutingContext context,
		CancellationToken cancellationToken = default(CancellationToken))
	{
		var scopeFactory = context.Request.HttpContext.RequestServices.GetService<IServiceScopeFactory>();
		context.Request.HttpContext.Features.Set<IServiceProvidersFeature>(new RequestServicesFeature(context.Request.HttpContext, scopeFactory));

		return base.BatchRequestExecutingAsync(context, cancellationToken);
	}

	public override Task BatchRequestExecutedAsync(
		BatchRequestExecutedContext context,
		CancellationToken cancellationToken = default(CancellationToken))
	{
		var requestServicesFeature = context.Request.HttpContext.Features.Get<IServiceProvidersFeature>() as RequestServicesFeature;
		requestServicesFeature.Dispose();

		return base.BatchRequestExecutedAsync(context, cancellationToken);
	}
}

[Tornhoof]

Hmm, interesting, yeah your workaround should do the trick, you can obviously also only just use set the delegate in the existing event handler, but your own type works just fine.
I specifically left things like DI untouched for the default features, because the expectations are different for each use case and the way different DI containers interact are also different.

[petronellius]

Without scoped sub-requests I am having problem with authorization. When I have two sub-request, both with invalid bearer token, I am getting unexpected response. First sub-request ends with 401 status code, second one with 200 status code. I have no idea where success status code comes from, because also second sub-request is not executed (action in controller is not called). I'd expect both sub-requests end with 401 status code.
It could be configuration option of middleware if sub-requests should be scoped or not.
Anyway, I am still happy to accomplish scoped sub-requests through event hooks.

[Lonli-Lokli]

@petronellius OData specification btw do not allow specific Authorization headers per request.