How to update "static_path" and "xstatic_url" on the fly in tornado?

I'm new to Tornado, and trying to understand how can i update the static_path on the fly. (The Xstatic will be similar i guess)

For example:

Application([
    ('/static1/(.*)', tornado.web.StaticFileHandler, dict(path='static1')),
    ('/static2/(.*)', tornado.web.StaticFileHandler, dict(path='static2')),
])

I want to be able to update the path on the fly, inside the implementation of one of those Handlers.

Is that even possible? I know there are tools like static_url_prefix and update the static_path via settings of tornado. But can i do it on the fly? during execution of one the Handlers.

My usecase: Why do i need it?

When i am connecting via proxy server to load the web page of the application, there is a header of "/proxy/aHR0cHM6Ly8xMC4xLjMuMTAwOjQ0Mw==/" added to the URL in the browser, so it probably changes the relative path and i need to adjust the location of the static sources accordingly. (currently the html page cannot find the static sources when proxy used)

The problem:

I cannot know if there is a proxy or not,when tornado is first loaded. I know that only later when one of the handlers catches the regex url.

Maybe i can somehow concatenate the proxy header to the static_urlparameter?

Thanks.