python - Can't call result() on futures in tornado -

i want asynchronous http-requests using python library tornado (version 4.2). can not force future complete (using result()) since exception: "dummyfuture not support blocking results".

i have python 3.4.3 therefore future support should part of standard library. documentation of concurrent.py says:

tornado use concurrent.futures.future if available; otherwise use compatible class defined in module.

a minimal example trying provided below:

from tornado.httpclient import asynchttpclient;  future = asynchttpclient().fetch("http://google.com") future.result() 

if understand problem correctly occurs because import of concurrent.futures.future somehow not used. relevant code in tornado appears in concurrent.py not making progress on understanding problem lies.

try create future , use add_done_callback:

from tornado documentation

from tornado.concurrent import future  def async_fetch_future(url):     http_client = asynchttpclient()     my_future = future()     fetch_future = http_client.fetch(url)     fetch_future.add_done_callback(         lambda f: my_future.set_result(f.result()))     return my_future 

but still need solve future ioloop, this:

# -*- coding: utf-8 -*- tornado.concurrent import future tornado.httpclient import asynchttpclient tornado.ioloop import ioloop   def async_fetch_future():     http_client = asynchttpclient()     my_future = future()     fetch_future = http_client.fetch('http://www.google.com')     fetch_future.add_done_callback(         lambda f: my_future.set_result(f.result()))     return my_future  response = ioloop.current().run_sync(async_fetch_future)  print(response.body) 

another way this, using tornado.gen.coroutinedecorator, this:

# -*- coding: utf-8 -*- tornado.gen import coroutine tornado.httpclient import asynchttpclient tornado.ioloop import ioloop   @coroutine def async_fetch_future():     http_client = asynchttpclient()     fetch_result = yield http_client.fetch('http://www.google.com')     return fetch_result  result = ioloop.current().run_sync(async_fetch_future)  print(result.body) 

coroutine decorator causes function return future.