ASP.NET Controller User property not working correctly

Question

I am trying to do something seemingly very simple. All I want to do is get the current Identity User's email address for my Blazor view. I have a UserEmailController in my Server project, with a GetCurrent() method that returns a Task<string>.

public class UserEmailsController : Controller
    {
        private readonly UserManager<ApplicationUser> _userManager;

        public UserEmailsController(UserManager<ApplicationUser> userManager)
        {
            _userManager = userManager;
        }

        [HttpGet]
        [Route("api/currentUser")]
        public async Task<string> GetCurrent()
        {
            var user = await _userManager.GetUserAsync(User);
            return await _userManager.GetEmailAsync(user);
        }
    }

From the spelunking I've done, it seems that the User property on the Controller base class should have the information loaded into it when a user is logged in, and I should be able to do something like await _userManager.GetUserAsync(User). However, when I break on this line, the Name property of User is null, along with many of the other values. But IsAuthenticated is true. Huh?

So, the result of the _userManager.GetUserAsync(User) call is null.

I've seen a few posts about this, and there are two common themes.

#1 - people try to use the User property in the constructor of a controller and it doesn't work. The suggested solution is to use it in an Action instead, which is of course what I'm doing.

#2 - another common suggestion is to use HttpContext.User, or to inject an IHttpContextAccessor (added via services.AddSingleton... or services.AddHttpContextAccessor()). I've tried all of these approaches and I get the same result.

Answer 1

I found a solution here. Specifically using HttpContext.User.FindFirst(ClaimTypes.NameIdentifier) and then passing that into _userManager.FindByIdAsync(nameId). Hell of a roundabout way of doing it, but it works.