So, I have a pretty basic need, but I can't figure out if it's even possible, much less how to do it.

I have a main page that anyone can see. Most of the rest of the application can be seen only if logged in (hence, a "set cookie"). So I was thinking, as long as they don't have a cookie set, they can just see a cached version of nginx. I can get it caching with this:

proxy_cache            STATIC;
proxy_cache_valid      200  1d;
proxy_cache_use_stale  error timeout invalid_header updating
                         http_500 http_502 http_503 http_504;

And it helps a ton. (instead of 15 requests per second it gets over 1000). Now I just need some sort of "server logic" to say only serve the cached page if they have no cookie, otherwise, load the dynamic page (which will automatically redirect them into the app).

Any ideas?