ASP.NET MVC: Enforce AJAX request on an action

Question

I'm looking for a way to enforce a controller's action to be accessed only via an AJAX request.

What is the best way to do this before the action method is called? I want to refactor the following from my action methods:

if(Request.IsAjaxRequest())
    // Do something
else
    // return an error of some sort

What I'm envisioning is an ActionMethodSelectorAttribute that can be used like the [AcceptVerbs] attribute. I have no experience crating such a custom attribute though.

Massotherapy

Answer 1

Create an ActionFilter that fires OnActionExecuting

public class AjaxActionFilter : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (!filterContext.HttpContext.Request.IsAjaxRequest())
            filterContext.Result = new RedirectResult(//path to error message);           
    }
}

Setting the filter's Result property will prevent execution of the ActionMethod.

You can then apply it as an attribute to your ActionMethods.

Honkytonk

+1, of the ways presented, this is by and far the one closest to my preferred approach and is extensible, especially if sited in a basecontroller that all others inherit from – Menadione

Answer 2

Its as simple as this:

public class AjaxOnly : ActionMethodSelectorAttribute
{
    public override bool IsValidForRequest(ControllerContext controllerContext, System.Reflection.MethodInfo methodInfo)
    {
        return controllerContext.HttpContext.IsAjaxRequest();
    }
}

I just forget where IsAjaxRequest() comes from, I'm pasting from code I have but "lost" that method. ;)

Gamma

Ooops, didn't get the part about returning an error. This makes it so the method will never get his unless the request is Ajax. Just another way to do it. – Gamma

I know this answer was posted aaaaaages ago but the IsAjaxRequest hangs off the request object not the Httpcontext. – Billups