python-3.x - 如何在 asyncio 实例中创建持久变量？

Question

我尝试编写一个基于 python3-asyncio 的回显服务器。我认为它可以在 asyncio 类的实例中存储和修改使用变量。

但我发现似乎所有连接都会创建一个新变量，因此它无法加载以前的值。

以下是异步服务器的代码：

class EchoServer(asyncio.Protocol):
    count = 0
    ts_last_update = 0

    def connection_made(self, transport):
        self.transport = transport
        ts_now = int(time.time())
        print('Previous count is:', self.count)
        self.count += 1                     # add 1 each connection
        if (ts_now - self.ts_last_update) > (3600 * 24):
            print('When expired, do something here.')
            self.ts_last_update = ts_now    # record last update timestamp

    def data_received(self, data):
        recv = data.decode()
        self.transport.write(('We got msg:{}'.format(recv)).encode())

结果如下，计数始终为 0。

Server agent running on ('127.0.0.1', 18888)
Connection accepted
Previous count is: 0
do something here.
Receive: [aa]
Connection accepted
Previous count is: 0
do something here.
Receive: [bb]
Connection accepted
Previous count is: 0