tornado－同步异步下载图片

同步下载，阻塞

from tornado.httpclient import HTTPClient

url = 'http://fafafiajwoachwe.jpeg'

client = HTTPClient()

result = client.fetch(url)

img = result.body

with open('media/image', 'wb') as f:

　　f.write(img)

异步（协程coroutine＋yield）下载，非阻塞

class GrabPicturesHandler(AuthBaseHandler):
    @tornado.gen.coroutine  # 1--------------
def post(self):
        url = self.get_argument('url')
        if not url:
            return self.write('no url')

        http_client = AsyncHTTPClient()
        try:
            response = yield http_client.fetch(url, request_timeout=6) #设置超时时间  # 2---------------
            with open('media/image/xx.jpg', 'wb') as f:
                f.write(response.body)
        except AttributeError as e:
            self.write(e)