Get list of custom attributes for current action/controller in ASP.NET MVC

问题

Checking out the sample code from http://lukesampson.com/post/471548689/entering-and-exiting-https-with-asp-net-mvc written for ASP.NET MVC2, I noticed they can check if a custom attribute is applied to the current action or controller by accessing filterContext.ActionDescriptor and filterContext.ActionDescriptor.ControllerDescriptor respectively:

public class ExitHttpsIfNotRequiredAttribute : FilterAttribute, IAuthorizationFilter {
    public void OnAuthorization(AuthorizationContext filterContext) {
        // snip

        // abort if a [RequireHttps] attribute is applied to controller or action
        if(filterContext.ActionDescriptor.ControllerDescriptor.GetCustomAttributes(typeof(RequireHttpsAttribute), true).Length > 0) return;
        if(filterContext.ActionDescriptor.GetCustomAttributes(typeof(RequireHttpsAttribute), true).Length > 0) return;

        // snip
    }
}

What would be the ASP.NET MVC 1 method of checking the action and controller for a custom attribute? In ASP.NET MVC 1 there is no filterContext.ActionDescriptor that I can tell.

回答1:

Even better and more reliable* approach:

filterContext.ActionDescriptor.GetCustomAttributes(
    typeof(RequireHttpsAttribute), true).Count> 0

Though this might be MVC 3.0+ only.

回答2:

Goldplated edition, works on MVC5, probably 4/3:

filterContext.HasMarkerAttribute<RequireHttpsAttribute>()

Uses this set of helper extensions:

public static class MarkerAttributeExtensions
{
    public static bool HasMarkerAttribute<T>(this AuthorizationContext that) {
        return that.Controller.HasMarkerAttribute<T>()
            || that.ActionDescriptor.HasMarkerAttribute<T>();
    }

    public static bool HasMarkerAttribute<T>(this ActionExecutingContext that) {
        return that.Controller.HasMarkerAttribute<T>()
            || that.ActionDescriptor.HasMarkerAttribute<T>();
    }

    public static bool HasMarkerAttribute<T>(this ControllerBase that) {
        return that.GetType().HasMarkerAttribute<T>();
    }

    public static bool HasMarkerAttribute<T>(this Type that) {
        return that.IsDefined(typeof(T), false);
    }

    public static IEnumerable<T> GetCustomAttributes<T>(this Type that) {
        return that.GetCustomAttributes(typeof(T), false).Cast<T>();
    }

    public static bool HasMarkerAttribute<T>(this ActionDescriptor that) {
        return that.IsDefined(typeof(T), false);
    }

    public static IEnumerable<T> GetCustomAttributes<T>(this ActionDescriptor that) {
        return that.GetCustomAttributes(typeof(T), false).Cast<T>();
    }
}

回答3:

This seems to work... is there a better / more proper way in ASP.NET MVC 1?

if (filterContext.Controller.GetType().GetCustomAttributes(typeof(RequireHttpsAttribute), true).Length > 0)
    return;
string action = (string)filterContext.RouteData.Values["action"];
if (!string.IsNullOrEmpty(action) && filterContext.Controller.GetType().GetMethod(action).GetCustomAttributes(typeof(RequireHttpsAttribute), true).Length > 0)
    return;

回答4:

I'm using MVC5 and had to use the following to check from within a class that inherits from ActionFilterAttribute and implements IAuthenticationFilter.

If filterContext.ActionDescriptor.GetCustomAttributes(GetType(RequireHttpsAttribute), True).Any() OrElse filterContext.ActionDescriptor.ControllerDescriptor.GetCustomAttributes(GetType(RequireHttpsAttribute), True).Any() Then
' .. the given attribute is present ..
End If

I couldn't get Ruben's solution to work for me but it was probably because I messed up in the conversion from C# to VB.

回答5:

this worked for me in .NET Core 2.2:

var controllerActionDescriptor = actionContext.ActionDescriptor as ControllerActionDescriptor;

        if (controllerActionDescriptor != null)
        {
            // Check if the attribute exists on the action method
            if (controllerActionDescriptor.MethodInfo?.GetCustomAttributes(inherit: true)?.Any(a => a.GetType().Equals(typeof(CustomAttribute))) ?? false)
                return true;

            // Check if the attribute exists on the controller
            if (controllerActionDescriptor.ControllerTypeInfo?.GetCustomAttributes(typeof(CustomAttribute), true)?.Any() ?? false)
                return true;
        }

来源：https://stackoverflow.com/questions/3569317/get-list-of-custom-attributes-for-current-action-controller-in-asp-net-mvc

标签

asp.net-mvc

custom-attributes

authorize-attribute