InvalidOperationException: Unable to resolve service for type 'Microsoft.AspNetCore.Http.IHttpContextAccessor'

Question

I started to convert my asp.net core RC1 project to RC2 and faced with problem that now IHttpContextAccessordoes not resolved.

For sake of simplicity I created new ASP.NET RC2 project using Visual Studio Template ASP.NET Core Web Application (.Net Framework). Than I added constructor for HomeController which template created for me.

public HomeController(IHttpContextAccessor accessor)
{
}

And after I start application I receive next error:

InvalidOperationException: Unable to resolve service for type 'Microsoft.AspNetCore.Http.IHttpContextAccessor' while attempting to activate 'TestNewCore.Controllers.HomeController'. в Microsoft.Extensions.Internal.ActivatorUtilities.GetService(IServiceProvider sp, Type type, Type requiredBy, Boolean isDefaultParameterRequired)

In my real application I need to resolve IHttpContextAccessor in my own service class for getting access to _contextAccessor.HttpContext.Authentication and to _contextAccessor.HttpContext.User. Everething works fine in RC1. So how can it suppose to be in RC2?

Answer 1

IHttpContextAccessor is no longer wired up by default, you have to register it yourself

services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();

Answer 2

As of .NET Core 2.1 there is an extension method that has been added to correctly register an IHttpContextAccessor as a singleton. See Add helper to register IHttpContextAccessor #947. Simply add as follows in your ConfigureServices() method:

services.AddHttpContextAccessor();

This is equivalent to:

services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();