ASP.NET Core Identity - get current user

To get the currently logged in user in MVC5, all we had to do was:

using Microsoft.AspNet.Identity;
[Authorize]
public IHttpActionResult DoSomething() {
    string currentUserId = User.Identity.GetUserId();
}

Now, with ASP.NET Core I thought this should work, but it throws an error.

using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Http;

private readonly UserManager<ApplicationUser> _userManager;
[HttpPost]
[Authorize]
public async Task<IActionResult> StartSession() {
    var curUser = await _userManager.GetUserAsync(HttpContext.User);
}

Any ideas?

EDIT: Gerardo's response is on track but to get the actual "Id" of the user, this seems to work:

ClaimsPrincipal currentUser = this.User;
var currentUserID = currentUser.FindFirst(ClaimTypes.NameIdentifier).Value;

Solution 1:

If your code is inside an MVC controller:

public class MyController : Microsoft.AspNetCore.Mvc.Controller

From the Controller base class, you can get the ClaimsPrincipal from the User property

System.Security.Claims.ClaimsPrincipal currentUser = this.User;

You can check the claims directly (without a round trip to the database):

bool isAdmin = currentUser.IsInRole("Admin");
var id = _userManager.GetUserId(User); // Get user id:

Other fields can be fetched from the database's User entity:

1. Get the user manager using dependency injection

   private UserManager<ApplicationUser> _userManager;
   
   //class constructor
   public MyController(UserManager<ApplicationUser> userManager)
   {
       _userManager = userManager;
   }
   

2. And use it:

   var user = await _userManager.GetUserAsync(User);
   var email = user.Email;
   

If your code is a service class, you can use dependency injection to get an IHttpContextAccessor that lets you get the User from the HttpContext.

    private IHttpContextAccessor _httpContextAccessor;

    public MyClass(IHttpContextAccessor httpContextAccessor)
    {
        _httpContextAccessor = httpContextAccessor;
    }

    private void DoSomething()
    {
        var user = _httpContextAccessor.Context?.User;
    }

Solution 2:

If you are using Bearing Token Auth, the above samples do not return an Application User.

Instead, use this:

ClaimsPrincipal currentUser = this.User;
var currentUserName = currentUser.FindFirst(ClaimTypes.NameIdentifier).Value;
ApplicationUser user = await _userManager.FindByNameAsync(currentUserName);

This works in apsnetcore 2.0. Have not tried in earlier versions.

Solution 3:

For context, I created a project using the ASP.NET Core 2 Web Application template. Then, select the Web Application (MVC) then hit the Change Authentication button and select Individual User accounts.

There is a lot of infrastructure built up for you from this template. Find the ManageController in the Controllers folder.

This ManageController class constructor requires this UserManager variable to populated:

private readonly UserManager<ApplicationUser> _userManager;

Then, take a look at the the [HttpPost] Index method in this class. They get the current user in this fashion:

var user = await _userManager.GetUserAsync(User);

As a bonus note, this is where you want to update any custom fields to the user Profile you've added to the AspNetUsers table. Add the fields to the view, then submit those values to the IndexViewModel which is then submitted to this Post method. I added this code after the default logic to set the email address and phone number:

user.FirstName = model.FirstName;
user.LastName = model.LastName;
user.Address1 = model.Address1;
user.Address2 = model.Address2;
user.City = model.City;
user.State = model.State;
user.Zip = model.Zip;
user.Company = model.Company;
user.Country = model.Country;
user.SetDisplayName();
user.SetProfileID();

_dbContext.Attach(user).State = EntityState.Modified;
_dbContext.SaveChanges();