JWT Authentication - UserManager.GetUserAsync returns null

Question

In AuthController when authenticating I create a few Claims - UserID is one of them.

...
Subject = new ClaimsIdentity(new[]
{
  new Claim(ClaimTypes.Name, user.UserName),
  new Claim("UserID", user.Id.ToString()),
})

When Angular app makes request I am able to fetch UserID in another controller

Claim claimUserId = User.Claims.SingleOrDefault(c => c.Type == "UserID");

The ControllerBase.User instance holds .Identity object which in turn holds Claims collection.

• Identity.IsAuthenticated equals True.

• Identity.Name holds admin string (name of the relevant user).

If I try to fetch user like this:

var user = await UserManager.GetUserAsync(HttpContext.User)

the user is null.

Perhaps, I forgot to add some extra claim?

Or maybe, once I'm using JWT - I should override the default UserManager functionality so it fetches user by claim which holds UserID?

Or maybe there's a better approach?

Additional info:

The Identity is registered as follows

services.AddIdentity<ApplicationUser, ApplicationRole>()
    .AddEntityFrameworkStores<AppDbContext>()
    .AddDefaultTokenProviders();

ApplicationUser.Id field is of bigint (or in C# of long) type

Also, I create users in EF Seed Data with UserManager which is resolved using ServiceProvider

_userManager = scope.ServiceProvider.GetService<UserManager<ApplicationUser>>();
    ...
        adminUser.PasswordHash = new PasswordHasher<ApplicationUser>().HashPassword(adminUser, "123qwe");
        _userManager.CreateAsync(adminUser);

Solution 1

UserManager.GetUserAsync internally uses UserManager.GetUserId to retrieve the user id of the user which is then used to query the object from the user store (i.e. your database).

GetUserId basically looks like this:

public string GetUserId(ClaimsPrincipal principal)
{
    return principal.FindFirstValue(Options.ClaimsIdentity.UserIdClaimType);
}

So this returns the claim value of Options.ClaimsIdentity.UserIdClaimType. Options is the IdentityOptions object that you configure Identity with. By default the value of UserIdClaimType is ClaimTypes.NameIdentifier, i.e. "http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier".

So when you try to use UserManager.GetUserAsync(HttpContext.User), where that user principal has a UserID claim, the user manager is simply looking for a different claim.

You can fix this by either switchting to the ClaimTypes.NameIdentifier:

new ClaimsIdentity(new[]
{
    new Claim(ClaimTypes.Name, user.UserName),
    new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
})

Or you configure Identity properly so it will use your UserID claim type:

// in Startup.ConfigureServices
services.AddIdentity(options => {
    options.ClaimsIdentity.UserIdClaimType = "UserID";
});

Solution 2

When you create Claims, you just need to do like:

 List<Claim> claims = new()
 {
    new Claim(ClaimTypes.NameIdentifier, user.Id),  // This line is important.
    new Claim(ClaimTypes.Email, user.Email),
    new Claim(JwtRegisteredClaimNames.Jti, jti)
 };

Comments

[Alex Riabov]

Could you share how you register Identity?

[Alex Herman]

hi @AlexRiabov, just answered your question, the code under Additional Info section.

[Rosdi Kasim]

Alternatively..., if userId is not available, one can use userManager.FindByNameAsync(username) instead if that fits the business requirement.

[mwilson]

Simply doing new Claim(ClaimTypes.NameIdentifier, user.Id) worked for me. Previously had this as user.UserName. Didn't realize the "name identifier" would be an Id. Who woulda thunk.

[poke]

@mwilson How you use the claims mostly depends on your application. There are different ways to approach this, and it also depends on what your id is.

[eaglei22]

Great solution. In my case, the Startup.ConfigureServices solution worked for me. Setting a breakpoint in the controller and navigating through the User->claims helped me realize which claim type my organization was using to get the userid. Then setting options.ClaimsIdentity.UserIdClaimType = ClaimTypes.[option] did it for me.

[ackh]

UserManager.GetUserAsync eventually calls the method FindByIdAsync of the IUserStore implementation which is helpful to know if you need to debug a custom IUserStore implementation.