Check whether the allow anonymous is on or not in ASP.NET Core

Question

I need a way to check if "allow anonymous" is on/off in the controller action. Whether it comes from controller attribute, action attribute

[AllowAnonymous]

or it is set as filter in the MvcOptions

opts.Filters.Add(new AllowAnonymousFilter());

Is it possible?

Answer 1

It seems you need to check whether a controller and action does contain AllowAnonymousAttribute from your custom authentication filter during a request. So you can do this as follows:

public class CustomAuthorizationFilter : IAsyncAuthorizationFilter
{
    public async Task OnAuthorizationAsync(AuthorizationFilterContext filterContext)
    {
        if (filterContext == null)
        {
            throw new ArgumentNullException(nameof(filterContext));
        }

        bool hasAllowAnonymous = filterContext.ActionDescriptor.EndpointMetadata
                                 .Any(em => em.GetType() == typeof(AllowAnonymousAttribute)); //< -- Here it is

        if (hasAllowAnonymous) return;

        // Do your authorization check here
    }
}