Using an MVC Action Filter to catch redirects in Ajax requests and return a JsonResult

Question

In my ASP.NET MVC 3 application, I have some action methods that can be invoked with Ajax and non-Ajax requests. The action methods may return a RedirectResult and I want th

Answer 1

Here's an example of how you could proceed:

public override void OnActionExecuted(ActionExecutedContext filterContext)
{
    base.OnActionExecuted(filterContext);

    if (filterContext.HttpContext.Request.IsAjaxRequest())
    {
        string url = "/";
        var redirectResult = filterContext.Result as RedirectResult;
        if (filterContext.Result is RedirectResult)
        {
            // It was a RedirectResult => we need to calculate the url
            var result = filterContext.Result as RedirectResult;
            url = UrlHelper.GenerateContentUrl(result.Url, filterContext.HttpContext);
        }
        else if (filterContext.Result is RedirectToRouteResult)
        {
            // It was a RedirectToRouteResult => we need to calculate
            // the target url
            var result = filterContext.Result as RedirectToRouteResult;
            url = UrlHelper.GenerateUrl(result.RouteName, null, null, result.RouteValues, RouteTable.Routes, filterContext.RequestContext, false);
        }
        filterContext.Result = new JsonResult
        {
            Data = new { Redirect = url },
            JsonRequestBehavior = JsonRequestBehavior.AllowGet
        };
    }
    else
    {
        // TODO: It is not an AJAX request => do whatever you were doing
    }
}