Question

I have the following controller:

[NoCache]
public class AccountController : Controller
{
    [Authorize(Roles = "admin,useradmin")]
    public ActionResult GetUserEntitlementReport(int? userId = null)
    {
        var byteArray = GenerateUserEntitlementReportWorkbook(allResults);

        return File(byteArray,
                System.Net.Mime.MediaTypeNames.Application.Octet,
                "UserEntitlementReport.xls");
    }
}

public class NoCache : ActionFilterAttribute
{
    public override void OnResultExecuting(ResultExecutingContext filterContext)
    {
        var response = filterContext.HttpContext.Response; 
        response.Cache.SetExpires(DateTime.UtcNow.AddDays(-1));
        response.Cache.SetValidUntilExpires(false);
        response.Cache.SetRevalidation(HttpCacheRevalidation.AllCaches);
        response.Cache.SetCacheability(HttpCacheability.NoCache);
        response.Cache.SetNoStore();
        base.OnResultExecuting(filterContext);
    }
}

As you can see, the controller is decorated with the [NoCache] attribute.

Is there any way to prevent this attribute from being applied to the GetUserEntitlementReport action?

I know I can remove the attribute at the controller level but that is not my favorite solution because the controller contains many other actions and i don’t want to have to apply the attribute to each action independently.

Answer 1

You could create a new Attribute which can be used on individual Actions to opt out of the NoCache specified at the controller level.

[AttributeUsage(AttributeTargets.Class |
                AttributeTargets.Method,
                AllowMultiple = false,
                Inherited = true)]
public sealed class AllowCache : Attribute { }

Mark any Actions where you want to allow caching with [AllowCache]

Then in the code for your NoCacheAttribute only disable caching if the AllowCache attribute is not present

public class NoCacheAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        base.OnActionExecuting(filterContext);

        var actionDescriptor = filterContext.ActionDescriptor;
        bool allowCaching = actionDescriptor.IsDefined(typeof(AllowCache), true) ||
            actionDescriptor.ControllerDescriptor.IsDefined(typeof(AllowCache), true);

        if(!allowCaching)
        {
            //disable caching.
        }
    }
}