CORS with gevent
Practically the only option in this situation is to switch to using WSGI. I ended up switching to pywsgi.WSGIServer, and the problem solved itself.
It's important to understand that switching to WSGI in reality introduces very little (if any) overhead, giving you so many benefits that the practical pros far outweigh the hypothetical cons.
I am building a gevent application in which I use gevent.http.HTTPServer. The application must support CORS, and properly handle HTTP OPTIONS requests. However, when OPTIONS arrives, HTTPServer automatically sends out a 501 Not Implemented, without even dispatching anything to my connection greenlet.
What is the way to work around this? I would not want to introduce an extra framework/web server via WSGI just to be able to support HTTP OPTIONS.