Adding custom claim not working in asp.net core identity

Question

I have created CustomClaimType to store user id:

public static class CustomClaimTypes
{
    public const string UserId = "UserId";
}

When user login, I set it:

var claims = new List<Claim>();
claims.Add(new Claim(ClaimTypes.Name, doc_session.ufname + " " + doc_session.ulname));
claims.Add(new Claim(CustomClaimTypes.UserId, doc_session.isci_id.Value.ToString()));
ClaimsIdentity userIdentity = new ClaimsIdentity(claims,"Identity.Application");
ClaimsPrincipal principal = new ClaimsPrincipal(userIdentity);

I have also created custom identity extension:

public static class IdentityExtensions
{
    public static int GetUserId(this IIdentity identity)
    {
        ClaimsIdentity claimsIdentity = identity as ClaimsIdentity;
        Claim claim = claimsIdentity?.FindFirst(CustomClaimTypes.UserId);

        if (claim == null)
            return 0;

        return int.Parse(claim.Value);
    }

    public static string GetName(this IIdentity identity)
    {
        ClaimsIdentity claimsIdentity = identity as ClaimsIdentity;
        Claim claim = claimsIdentity?.FindFirst(ClaimTypes.Name);

        return claim?.Value ?? string.Empty;
    }
}

But when I call User.Identity.GetUserId(); I get 0 (null) as result.

Answer 1

For adding extra claims to Identity, you could implement custom CustomClaimsPrincipalFactory.

1. CustomClaimsPrincipalFactory

   public class CustomClaimsPrincipalFactory : UserClaimsPrincipalFactory<IdentityUser<int>>
   {
       public CustomClaimsPrincipalFactory(UserManager<IdentityUser<int>> userManager,
                                               IOptions<IdentityOptions> optionsAccessor)
       : base(userManager, optionsAccessor)
       {
       }
   
       public async override Task<ClaimsPrincipal> CreateAsync(IdentityUser<int> user)
       {
           var principal = await base.CreateAsync(user);
   
           // Add your claims here
           ((ClaimsIdentity)principal.Identity).AddClaims(
               new[] { new Claim(ClaimTypes.Name, user.UserName),
               new Claim(CustomClaimTypes.UserId, user.Id.ToString())
               });
   
           return principal;
       }
   }
   

2. Register CustomClaimsPrincipalFactory

   public void ConfigureServices(IServiceCollection services)
   {
       services.Configure<CookiePolicyOptions>(options =>
       {
           // This lambda determines whether user consent for non-essential cookies is needed for a given request.
           options.CheckConsentNeeded = context => true;
           options.MinimumSameSitePolicy = SameSiteMode.None;
       });
   
       services.AddDbContext<ApplicationDbContext>(options =>
           options.UseSqlServer(
               Configuration.GetConnectionString("DefaultConnection")));
       services.AddDefaultIdentity<IdentityUser<int>>()
           .AddEntityFrameworkStores<ApplicationDbContext>();
       services.AddScoped<IUserClaimsPrincipalFactory<IdentityUser<int>>, CustomClaimsPrincipalFactory>();
       services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
   }
   

3. IdentityExtensions

   public static class IdentityExtensions
   {
       public static int GetUserId(this ClaimsPrincipal identity)
       {
           Claim claim = identity?.FindFirst(CustomClaimTypes.UserId);
   
           if (claim == null)
               return 0;
   
           return int.Parse(claim.Value);
       }
   
       public static string GetName(this ClaimsPrincipal identity)
       {
           Claim claim = identity?.FindFirst(ClaimTypes.Name);
   
           return claim?.Value ?? string.Empty;
       }
   }
   

4. Useage

   public IActionResult About()
   {
       var claims = User.Claims;
       var userId = User.GetUserId();
       var userName = User.GetName();
       ViewData["Message"] = "Your application description page.";
   
       return View();
   }