api.py

import tornado.ioloop
import tornado.web
import json

class MainHandler(tornado.web.RequestHandler):
    def get(self, type_r=None):
        format_answer = self.get_argument("format", "json")
        # bla bla request to postgres
        if format_answer == "sql":
          self.write(my_sql_answer)
        else:
          self.set_header('Content-Type', 'application/json')
          self.write(json.dumps(my_json_objetc_asnwer)

def make_app():
    return tornado.web.Application([
        (r"/gen1", MainHandler, "gen_1"),
        (r"/gen2", MainHandler, "gen_2"),
        (r"/gen3/(.*)", MainHandler)
    ])

if __name__ == "__main__":
    app = make_app()
    app.listen(8888)
    tornado.ioloop.IOLoop.current().start()