My problem is the infamous "StatusCodeException: 0" problem happening when using GWT 2.6.1 when accessing page via subdomain https://sub.site.com/.
Now, this happens quite sporadically for one customer using IE11 and I can't reproduce this from several distinct computers using IE11, IE10, IE9 or IE8 (not to talk about Chrome or Firefox).
Accessing exactly the same webapp from https://site.com/ seems to work fine for that customer.
This obviously lead me to conclusion that I'm having problem with Same Origin Policy.
What is strange though is that my webapp is designed in the way that no cross-domain or cross-subdomain requests are made. Same goes for no cross-protocol as well no cross-port requests. In other words, Same Origin Policy is not violated in this situation. As a confirmation of that, I can provide following proof:
While being at customer site I've seen how this is reproduced: customer starts using application and everything works fine - all requests are returning response normally. Then, after several minutes of working, exactly the same requests on the same page (without reloads) starts to fail with StatusCodeException: 0.
Basically, both https://sub.site.com and https://site.com points to the same IP, and there is only one Tomcat webapp serving exactly the same resources both for https://sub.site.com and https://site.com.
Another proof would be the codebase of the single GWT module itself: there I use only one instance of one service called DashboardService:
public class DashboardModule extends EntryPoint implements IDashboardModule {
private final DashboardServiceAsync dashboardService = createDashboardService();
@Override
public void onModuleLoad() {
// loading of module elements
// dashboardService is passed as a parameter so only one instance is used
}
/**
* PLEASE SEE QUESTION #1 BELOW CODE SNIPPET
*/
private static final String DASHBOARD_REQUEST_URL = "request";
private static DashboardServiceAsync createDashboardService() {
final DashboardServiceAsync service = GWT.create(DashboardService.class);
((ServiceDefTarget) service).setServiceEntryPoint(DASHBOARD_REQUEST_URL);
return service;
}
}
=================================== EDIT ====================================
After looking in the console at customer location, the error was always the following:
SCRIPT7002: XmlHttpRequest: network error 0x2ee4, ...
so it seems that this has nothing to do with Same-Origin Policy, because as per this article it is described as ERROR_INTERNET_INTERNAL_ERROR An internal error has occurred.
It's a pity, but I've found only 2 mentions of this error which were not resolved: Error under IE10 and Error under IE11.
I have an assumption that customer is very probably accessing site through some proxy which slightly changes the requests and IE can't handle them.
Question 1: does anybody knows how can I simulate or reproduce mentioned error locally?
Question 2: does anybody knows how this problem can be gracefully worked around?
Question 3: is it ok to simply retry the request, or this request may have reached the server and modify it, so retrying it may produce duplicate modification?
Will try to setup forwarding proxy to simulate possible customer setup to at least reproduce mentioned error...
I greatly appreciate any help!
https://site.com/for that customer. – Jackinthepulpit