How to get current User outside of Controller in another layer

Question

In ASP.NET Core 6, I need to get the current user in service layer

This is code:

public class ServiceModel
{
    private readonly IHttpContextAccessor accessor;

    public ServiceModel(IHttpContextAccessor accessor)
    {
        this.accessor = accessor;
    }
}

But User is always Null:

var user = accessor.HttpContext?.User

Code in Program file:

builder.Services.AddIdentity<AppUser, AppRole>(options =>
{
    options.User.AllowedUserNameCharacters =
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._@+/ ";
    options.User.RequireUniqueEmail = false;
})
.AddEntityFrameworkStores<testContext>()
.AddUserManager<UserManager<AppUser>>()
.AddClaimsPrincipalFactory<ApplicationUserClaimsPrincipalFactory>()
.AddDefaultTokenProviders();

builder.Services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
.AddCookie(options =>
{
    options.Cookie.Name = "MyAppCookie";
    options.LoginPath = "/Account/Login";
});

builder.Services.AddHttpContextAccessor();

This the packages installed in Service Layer:

Microsoft.AspNetCore.Identity.EntityFrameworkCore
Microsoft.EntityFrameworkCore
Microsoft.AspNetCore.Mvc.ViewFeatures

Answer 1

Although I do not know how do create the object of ServiceModel class and use it, I provide a sample code assuming you want to log the username.

Below is a sample of ASP.NET Core 6.0 MVC based on Microsoft document Access HttpContext from custom components:

UserRepository class

Assume this is your ServiceModel class.

namespace MvcCore6App3.Libraries
{
    public class UserRepository : IUserRepository
    {
        // inject IHttpContextAccessor object by DI
        private readonly IHttpContextAccessor _httpContextAccessor;
        private readonly ILogger<UserRepository> _logger;

        public UserRepository(IHttpContextAccessor httpContextAccessor,
                              ILogger<UserRepository> logger)
        {
            _httpContextAccessor = httpContextAccessor;
            _logger = logger;
        }

        public void LogCurrentUser()
        {
            // Get login user name
            var username = _httpContextAccessor.HttpContext?
                           .User.Identity?.Name;
            if (username != null)
            {
                _logger.LogInformation($"{username} access on {DateTime.Now}");
            }
            else
            {
                _logger.LogInformation($"anonymous access on {DateTime.Now}");
            }
        }
    }

    public interface IUserRepository
    {
        public void LogCurrentUser();
    }
}

Program.cs

Note that ASP.NET Core Identity is enabled and username is obtained form it.

using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using MvcCore6App3.Data;
using MvcCore6App3.Libraries;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");

builder.Services.AddDbContext<ApplicationDbContext>(options =>
    options.UseSqlServer(connectionString));

builder.Services.AddDatabaseDeveloperPageExceptionFilter();

builder.Services.AddDefaultIdentity<IdentityUser>(options => options.SignIn.RequireConfirmedAccount = true)
    .AddEntityFrameworkStores<ApplicationDbContext>();

builder.Services.AddControllersWithViews();

// 2024/9/19 Add IHttpContextAccessor and UserReposirty to DI container
builder.Services.AddHttpContextAccessor();
builder.Services.AddTransient<IUserRepository, UserRepository>();

// Code omitted below

Controller

using Microsoft.AspNetCore.Mvc;
using MvcCore6App3.Models;
using System.Diagnostics;

namespace MvcCore6App3.Controllers
{
    public class HomeController : Controller
    {
        private readonly Libraries.IUserRepository _userRepository;

        public HomeController(Libraries.IUserRepository userRepository)
        {
            _userRepository = userRepository;
        }

        public IActionResult Index()
        {
            // get current user name and log it outside of Controller
            _userRepository.LogCurrentUser();
            return View();
        }
        
        // code omitted
    }
}

Result

Answer 2

for your ServiceModel to access HttpContextAccessor, it needs to be registered as a service:

builder.Services.AddTransient<ServiceModel, ServiceModel>();

then injected into _Layout.cshtml:

@inject ServiceModel service