Question

As the title says, i want to retrieve my Json data values from a XMLHttpRequest. I already know how to do it by using a common success $.Ajax success event, but i want to get it’s values from an error event. A thing that i noticed is not simple to find all kinds of a XMLHttpRequest types.

To explain a little more, here’s the scenario: after some inactivity, the user sessions expires. If he tries to do any operations using an Ajax call, he’ll be redirected to the login page. I handle this session timeout error on a particular filter that implements an OnException method.

While i can do it using a sort of a hack (by setting manually the HTTP response code), i’d like to do it on “proper way”, with no hacks.

OnException method code snippet

filterContext.ExceptionHandled = true;

        // If this is an ajax request, return the exception in the response
        if (filterContext.HttpContext.Request.IsAjaxRequest())
        {
            //If the session has expired, throws a SESSION TIMEOUT error
            if (Session["UserLogged"] == null)
            {
                //The hack mentioned before
                filterContext.HttpContext.Response.StatusCode = 502;
                filterContext.Result = new JsonResult()
                {
                    Data = new { success = false, errorType = "SESSION_TIMEOUT" ,error = filterContext.Exception.ToString() },
                    JsonRequestBehavior = JsonRequestBehavior.AllowGet
                };  
            }

}

So, by using a simple $.Ajax Error Event, how would i retrive the data from the filterContext.Result? Specifically the errorType parameter.

Answer 1

You should be able to parse the JSON data out of the jqXHR responseText property in your error handler.

error: function(jqXHR, textStatus, errorThrown) {
          alert('jqXHR.responseText = ' + jqXHR.responseText);
        }