icarus/Authorization/Handlers/HasScopeHandler.cs

using System;
using System.Linq;
using System.Threading.Tasks;

using Microsoft.AspNetCore.Authorization;

using Icarus.Authorization;

namespace Icarus.Authorization.Handlers
{
    public class HasScopeHandler : AuthorizationHandler<HasScopeRequirement>
    {
        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, HasScopeRequirement requirement)
		{
			if (!context.User.HasClaim(c => c.Type == "scope" && c.Issuer == requirement.Issuer))
			{
				return Task.CompletedTask;
			}

			var scopes = context.User.FindFirst(c =>
				c.Type == "scope" && c.Issuer == requirement.Issuer).Value.Split(' ');

			if (scopes.Any(s => s == requirement.Scope))
			{
				context.Succeed(requirement);
			}

			return Task.CompletedTask;
		}
    }
}