A hack to make Tornado web server redirect http requests to https for Heroku or similar reverse-proxied deployments

tornado_force_https.py

from __future__ import absolute_import, print_function

import os

import tornado.httpserver
import tornado.ioloop
import tornado.web

def create_server(*args, **kwargs):
    '''
    Makes HTTPServer based on 'args' & 'kwargs' that have the same meaining
    as in HTTPServer's constructor.
    If xheaders=True and force_https=True are passed, also patches _RequestDispatcher
    to generate redirects to https URLs.
    '''
    kw = dict(kwargs)
    force_https = kw.pop('force_https', False)
    if kw.get('xheaders', False) and force_https:
        class PatchedDispatcher(tornado.web._RequestDispatcher):
            def _find_handler(self):
                req = self.request
                if req.headers.get('X-Forwarded-Proto') != 'https':
                    self.handler_class = tornado.web.RedirectHandler
                    self.handler_kwargs = {'url': 'https://%s%s' % (req.headers['Host'], req.uri)}
                    return
                return super(PatchedDispatcher, self)._find_handler()
        tornado.web._RequestDispatcher = PatchedDispatcher
    return tornado.httpserver.HTTPServer(*args, **kw)

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")

app = tornado.web.Application([
    (r"/", MainHandler),
])

server = create_server(app,
                       xheaders=True,
                       force_https=os.environ.get('FORCE_HTTPS') in ('true', 'True'))
server.listen(int(os.environ['PORT']))
tornado.ioloop.IOLoop.current().start()