server.py

import time
import logging
import functools

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

from tornado.options import define, options

define("port", default=8888, help="run on the given port", type=int)

class Longrunner(object):
    def do_later(self, evilbit, on_success, on_error):
        logging.info("doing application stuff...")
        if evilbit:
            on_error("oops!")
        else:
            on_success("ok!")
        logging.info("doing some application clean up...")


class MainHandler(tornado.web.RequestHandler):
    @tornado.web.asynchronous
    def get(self):
        delay = int(self.get_argument("delay", 0))
        error = self.get_argument("error", None)
        longrunner = functools.partial(Longrunner().do_later,
                                       error,
                                       self.async_callback(self.on_success),
                                       self.async_callback(self.on_error))
        tornado.ioloop.IOLoop.instance().add_timeout(time.time() + delay,
                                                     longrunner)
    
    def on_success(self, data):
        self.write(data)
        self.finish()

    def on_error(self, data):
        raise tornado.web.HTTPError(400)


def main():
    tornado.options.parse_command_line()
    application = tornado.web.Application([
        (r"/", MainHandler),
    ])
    http_server = tornado.httpserver.HTTPServer(application)
    http_server.listen(options.port)
    tornado.ioloop.IOLoop.instance().start()


if __name__ == "__main__":
    main()