Question

鉴于龙卷风处理程序如下：

class MyHandler(tornado.web.RequestHandler):

    @tornado.gen.coroutine
    def get(self):
        queue = self.getQueue() # returns a tornado.queues.Queue
        _ = yield queue.get()
        self.write("whatever")

    def on_connection_close(self):
        super().on_connection_close()
        # DO SOMETHING HERE THAT BREAKS OUT OF THE YIELD UP THERE??

如果连接关闭，我真的不想在队列中保持阻塞，以后错误地取消一个值。我可以设置一种机制来中止被阻止的get()方法吗？

Answer 1

Use chain_future. Chain queue.get's future with some other future that is in your control (some kind of indicator/flag), then simply resolve flag future on close:

from tornado.concurrent import Future, chain_future

class MyHandler(tornado.web.RequestHandler):

    def initialize(self):
        # of course you can create that in get as well
        self.close_indicator = Future()

    @tornado.gen.coroutine
    def get(self):
        queue = self.getQueue() # returns a tornado.queues.Queue
        qget_future = queue.get()
        chain_future(self.close_indicator, qget_future) 
        _ = yield qget_future
        self.write("whatever")

    def on_connection_close(self):
        super().on_connection_close()
        # set close indicator by resolving future
        # result will be copied to chained future (qget_future)
        self.close_indicator.set_result(None)

在on_connection_close（）时解锁tornado.queues.Queue.get（）协同程序？

1 个答案: