ASP.NET Core 2.1 Jwt setting custom claims - asp.net

Question

I have this code that is supposed to set claims for a user. It works fine when I use identity and the default login. However, when I use jwt as authentication in another application, I don't have ApplicationUser as my ApplicationUser is stored in the other application that authenticates the user. How can I customize this code so that it works with jwt?
private readonly SignInManager<TIdentityUser> _signInManager;
public CustomClaimsCookieSignInHelper(SignInManager<TIdentityUser> signInManager)
{
_signInManager = signInManager;
}
public async Task SignInUserAsync(TIdentityUser user, bool isPersistent, IEnumerable<Claim> customClaims)
{
var claimsPrincipal = await _signInManager.CreateUserPrincipalAsync(user);
var identity = claimsPrincipal.Identity as ClaimsIdentity;
var claims = (from c in claimsPrincipal.Claims select c).ToList();
var savedClaims = claims;
if (customClaims != null)
{
identity.AddClaims(customClaims);
}
await _signInManager.Context.SignInAsync(IdentityConstants.ApplicationScheme,
claimsPrincipal,
new AuthenticationProperties { IsPersistent = isPersistent });
}
I guess my main intention is to set my users claims in the httpcontext and not in a cookie and I want to do that without using identity.
EDIT:
My application structure
AuthenticationApp (server)
Responsible for authenticating users
Generates and Decodes Jwt
Checks if the user has the appropriate roles and returns true/false via rest api
MainApp (client)
Makes an api call to AuthenticationApp
Does not use identity at all
Sends Jwt everytime I need to check the role of the user
I understand that I will be able to decode the jwt client side. However, I do not know where I can store the decoded jwt details so that I can use it in the view. My initial idea was to use Httpcontext like normal applications that user Identity. However, I am stuck with the code above.

Answer 1

For sharing the Identity information between Controller and View, you could sign the User information by HttpContext.SignInAsync.
Try steps below to achieve your requirement:
Controller Action
public async Task<IActionResult> Index()
{
var identity = new ClaimsIdentity(CookieAuthenticationDefaults.AuthenticationScheme, ClaimTypes.Name, ClaimTypes.Role);
identity.AddClaim(new Claim(ClaimTypes.NameIdentifier, "edward"));
identity.AddClaim(new Claim(ClaimTypes.Name, "edward zhou"));
//add your own claims from jwt token
var principal = new ClaimsPrincipal(identity);
await HttpContext.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, principal, new AuthenticationProperties { IsPersistent = true });
return View();
}
View
#foreach (var item in Context.User.Claims)
{
<p>#item.Value</p>
};
To make above code work, register Authentication in Startup.cs
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
//your rest code
services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme).AddCookie();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
//your rest code
app.UseAuthentication();
app.UseMvc(routes =>
{
routes.MapRoute(
name: "default",
template: "{controller=Home}/{action=Index}/{id?}");
});
}
}