Getting the current user (aspnetcore identity)

Question

I'm trying to get the id of the current user (the user executing the method) with Identity package. The context is a UserManager<ApplicationUser> (ApplicationUser is an IdentityUser).

var currentUserId = User.FindFirst(ClaimTypes.NameIdentifier).Value;

I add this to the list of claims when a user logs in. 'user' is the ApplicationUser from the DB.

new Claim(ClaimTypes.NameIdentifier, user.Id),

I also used this doc and added the following in Program.cs.

builder.Services.Configure<IdentityOptions>(options =>
    options.ClaimsIdentity.UserIdClaimType = ClaimTypes.NameIdentifier);

However, I keep getting an "System.NullReferenceException: 'Object reference not set to an instance of an object.'" error.

The link also showed that I could get the current user as

var user = await userManager.GetUserAsync(User);

However, that just made the user null.

I'm using postman/swagger for debugging.

Here is the entire stack trace:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Server.Authentication.Controllers.AuthController.UpdateUser(String id, UpdateModel model) in C:\i2\PromoCreate\promocreate\Server\Authentication\Controllers\AuthController.cs:line 168
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|20_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Can someone tell me what I'm doing wrong?

Answer 1

I'm answering my own question. I simply needed the [Authorize] attribute above the method.