A Sunlight subclass that uses Tornado's AsyncHTTPClient instead of urllib2

tornado_sunlight.py

from sunlight import Sunlight, SunlightError, RESPONSE_KEYS
from tornado import escape, httpclient

class TornadoSunlight(Sunlight):
    """
    Subclassing Sunlight (from simple-sunlight) to use Tornado's AsyncHTTPClient
    """
    def __init__(self, *args, **kwargs):
        super(TornadoSunlight, self).__init__(*args, **kwargs)
        self.client = httpclient.AsyncHTTPClient()
    
    def __call__(self, **params):
        params['apikey'] = self.apikey
        url = BASE_URL % (self.method, urllib.urlencode(params))
        return self.client.fetch(url, self._on_response)
        
    def _on_response(self, response):
        if response.error:
            raise SunlightError(response.error)
        
        yield escape.json_decode(response.body)['response'][RESPONSE_KEYS[self.method]]