Ajax request hitting error function before HandleUnauthorizedRequest

Question

I have an PhoneGap app that is communicating with a C# service for it's data. The user has to be logged in for them to access any of this so I have a AuthorizeAttribute on my controller. This works fine and rightly, throws an to my app. The problem for me is that in my AuthorizeAttribute I am overriding the HandleUnauthorizedRequest method and it should be returning a 401. In fact, it probably is, it's just that the Ajax handler hits the error function before my override method has returned.

AuthorizeAttribute

public class AppCustomAuthorization : AuthorizeAttribute
{
    protected override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
    {
        filterContext.HttpContext.Response.StatusCode = 401;
        filterContext.HttpContext.Response.End();

        base.HandleUnauthorizedRequest(filterContext);
    }
}

Ajax

$.ajax({
    type: "GET",
    url: url + "checkin/app/info",
    dataType: "json",
    success: function(d) {
        // Do stuff
    },
    error: function (xhr, textStatus, errorThrown) {
        app.showError(errorThrown); // Status code is 0
    }
});

When I look at the Network requests, it seems that my get request is cancelled. Originally, I assumed this is because my authorize attribute is causing it cancel the request, but then, it seems to cancel before it hits my handler.

Answer 1

This might be because of the Same Origin Policy. Check this out:

http://docs.phonegap.com/en/1.9.0/guide_whitelist_index.md.html

Answer 2

Just in order to close the complete the question, the reason I was seeing a response code of 0 is because:

A status code of "0" usually means the user navigated to a different page before the AJAX call completed

I got this from this SO answer, which has over 70,000 views at the time of writing, so I guess this problem can occur a lot. This obviously led me to look at what could be causing my app to navigate elsewhere and sure enough, in my code I had:

$('[data-role=page]').on('pageshow', function (event, ui) {
if ($(location).attr('pathname').indexOf('login.html') == -1)
    if (window.localStorage['UserName'] == null || window.localStorage['Password'] == null) 
        window.location = "login.html";
}):

As a workaround from the early stages of development from the app as a primitive type of checking the user was actually logged in.