Is there anything in this MVC code that could be environment dependent?

See more:

Ajax

MVC

jQuery

web_development

Last week I discovered a bug where, after session timeout, any ajax request would be automatically redirected back to the Login action. The ajax request would then 'blow up' on the client. I easily reproduced the bug by deleting cookies and attempting a new ajax request. Then I thought I had solved the problem with the following code combination.

Client:

$.acme.global.dataAccess = function() {
	var dataAccess = {};

	Object.defineProperty(this, "httpHeaderAjax", { value: "Acme-Is-Ajax-Request", writeable: true });

	var defaultHeaders = {};
	defaultHeaders[httpHeaderAjax] = true;
   
	dataAccess.genericErrorFunction = function (response) {
		
		if (response.status == 401) {
			var returnUrl = location.pathname + location.search;
			location.href = "/Account/Login?returnUrl=" + encodeURIComponent(returnUrl);
		}
		else if (!(response.status == 302) && !(response.status == 0) &&!(response.status==200)) {
			location.href = "Error/?exceptionMessage=" + response.responseText;
		}
	};

	dataAccess.submitAjaxPostJsonRequestWithErrorFunction = function (targetUrl, jsonData, successFunction, errorFunction) {
	   
		var jsonString = JSON.stringify(jsonData);
		
		$.ajax({
			type: 'POST',
			url: targetUrl,
			data: jsonString,
			headers: defaultHeaders,
			crossDomain: true,
			success: successFunction,
			error: errorFunction,
			contentType: "application/json",
			dataType: 'json'
		});
	};

	return dataAccess;
}();

Server:

public class AccountController: BaseController
{
	[AllowAnonymous]       
	public  ActionResult Login(string ReturnUrl = "")
	{
		var ajaxHeader = Request.Headers[HttpConstants.RequestHeaders.ThreeFifteenIsAjaxRequest] ?? "false";
		if (ajaxHeader == "true")
		{
			return new HttpUnauthorizedResult("Ajax request was redirected to Login action.");
		}
		if (ReturnUrl == "/Home/LogOff")
		{
			ReturnUrl = "/";
		}

		return View(AuthenticationProvider.Providers(ReturnUrl));
	}
}

This works fine on my local machine, and on our dev environment, an Azure Web Site, but when I deploy it to our staging site, another Azure Web Site, the ajax problem is still unresolved. Putting a browser break-point in genericErrorFunction shows an expected 401 response locally and on dev, but on staging all I can see on the response object are the functions set by the ajax call.

Nothing in the code above seems to be environment dependent - it feels pretty hard and explicit to me - but I am desperately looking for possible explanations here.