龙卷风@ web.asynchronous @ gen.coroutine VS @ gen.corutine有什么区别

Question

在文档中,如果方法也用@ gen.coroutine修饰,则不需要@ web.asynchronous.像这样

@web.asynchronous
@gen.coroutine
def get(self):
    ...

但是,在文档中,他们还解释说如果你使用@ web.asynchronous,那么你应该调用self.finish().但是,在上面的情况下(一起使用两个装饰器)连接完成后调用"self.finish()"

我想知道那里发生了什么.

在下面的情况下,它与上述不同.

@web.asynchronous
def get(self):
    self.test()

@gen.coroutine
def test(self):
    httpClient = AsyncHttpClient()
    val = yield httpClient.fetch("http://www.google.com")
    print test
    #self.finish()

如果未调用"self.finish()",则表示连接未关闭.

有人可以解释一下吗？

Answer 1

秘密在这里:

if isinstance(result, Future):
    # If @asynchronous is used with @gen.coroutine, (but
    # not @gen.engine), we can automatically finish the
    # request when the future resolves.  Additionally,
    # the Future will swallow any exceptions so we need
    # to throw them back out to the stack context to finish
    # the request.
    def future_complete(f):
        f.result()
        if not self._finished:
            self.finish()
    IOLoop.current().add_future(result, future_complete)

@asychronous检查返回未来的方法(即@gen.coroutine),如果是,则添加IOLoop回调以在将来完成时完成连接.