How do I access claims inside an AuthorizationHandler? - asp.net-core

Question

I found this resource for creating an AuthorizationHandler and followed along to create one. My handler checks for given_name, a string value, and if given_name has a value of "Bob", authorization success.
The problem, I can't access the given_name claim and its value. I can see all the expected claims when I inspect context.User but context.User.HasClaim(c => c.Type == ClaimTypes.GivenName) always returns false.
How do I check for the presence of a claim and get its value?
Update - As a workaround, I can access all the claims by calling .ToList() on context.User.Claims and then using .Any() on the list. It works but I haven't seen this approach in any examples.

Answer 1

For Asp.NET Core 6, you can pass in the AuthorizationHandlerContext.
Here is a sample AuthorizationHandler that leverages that context for a ClaimsPrincipal.
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc.Filters;
namespace MyIdentityApp.Security
{
public class CanReadAffiliatedOwnerInfoHandler : AuthorizationHandler<ManageAffiliatedOwnerInfoRequirement>
{
protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, ManageAffiliatedOwnerInfoRequirement requirement)
{
var authFilterContext = (HttpContext?)context.Resource;
if (authFilterContext == null)
{
return Task.CompletedTask;
}
else
{
//access user's claims here, via context.User
var loggedInUserAffiliatedOwners = context.User.Claims.FirstOrDefault(c => c.Value == OwnerIdAttemptingToAccess);
if (loggedInUserAffiliatedOwners != null)
{
context.Succeed(requirement);
}
}
return Task.CompletedTask;
}
}
}