python - Tornado redis错误: "finish() called twice"

Question

class RedisHandler(BaseHandler):
@tornado.web.authenticated
@tornado.web.asynchronous
@tornado.gen.engine
def post(self):
    self.client = tornadoredis.Client()
    self.client.connect()
    yield tornado.gen.Task(self.client.subscribe,'notification')
    self.client.listen(self.on_message)

def on_message(self,msg):
    if msg.kind == 'message':
        self.finish(dict(complete=True,message=msg.body))
    return

上面的代码引发了:

RuntimeError: finish() called twice

可能是没有@asynchronous装饰器使用异步操作导致的。

Answer 1

可能是因为你在调用self.finish()的时候没有取消订阅/断开Redis的连接，所以当另一条消息到达时，调用了on_message()再次:

def on_message(self,msg):
    if msg.kind == 'message':

        self.finish(dict(complete=True,message=msg.body))

        self.client.unsubscribe('notification')
        self.client.disconnect()