在 Python 3.6 上的 websocket 客户端中监听传入消息的问题

Question

我正在尝试使用此处的 websockets 包在 Python 上构建 websocket 客户端：Websockets 4.0 API

我使用这种方式而不是示例代码，因为我想创建一个 websocket 客户端类对象，并将其用作网关。

我在客户端的侦听器方法 (receiveMessage) 有问题，这会在执行时引发 ConnectionClose 异常。我认为循环可能有任何问题。

这是我尝试构建的简单 webSocket 客户端：

import websockets

class WebSocketClient():

    def __init__(self):
        pass

    async def connect(self):
        '''
            Connecting to webSocket server

            websockets.client.connect returns a WebSocketClientProtocol, which is used to send and receive messages
        '''
        self.connection = await websockets.client.connect('ws://127.0.0.1:8765')
        if self.connection.open:
            print('Connection stablished. Client correcly connected')
            # Send greeting
            await self.sendMessage('Hey server, this is webSocket client')
            # Enable listener
            await self.receiveMessage()


    async def sendMessage(self, message):
        '''
            Sending message to webSocket server
        '''
        await self.connection.send(message)

    async def receiveMessage(self):
        '''
            Receiving all server messages and handling them
        '''
        while True:
            message = await self.connection.recv()
            print('Received message from server: ' + str(message))

这是主要的：

'''
    Main file
'''

import asyncio
from webSocketClient import WebSocketClient

if __name__ == '__main__':
    # Creating client object
    client = WebSocketClient()
    loop = asyncio.get_event_loop()
    loop.run_until_complete(client.connect())
    loop.run_forever()
    loop.close()

为了测试传入消息侦听器，服务器在建立连接时向客户端发送两条消息。

客户端正确连接到服务器，并发送问候语。但是，当客户端收到两条消息时，它会引发 ConnectionClosed 异常，代码为 1000（没有原因）。

如果我在 receiveMessage 客户端方法中删除循环，客户端不会引发任何异常，但它只接收一条消息，所以我想我需要一个循环来保持侦听器处于活动状态，但我不知道确切的位置或方式.

有什么解决办法吗？

提前致谢。

编辑：我意识到客户端在收到来自服务器的所有待处理消息时会关闭连接（并中断循环）。但是，我希望客户能够继续聆听未来的消息。

此外，我尝试添加另一个函数，其任务是向服务器发送“心跳”，但客户端仍然关闭连接。

Answer 1

最后，基于这个post 的回答，我这样修改了我的客户端和主文件：

WebSocket 客户端：

import websockets
import asyncio

class WebSocketClient():

    def __init__(self):
        pass

    async def connect(self):
        '''
            Connecting to webSocket server

            websockets.client.connect returns a WebSocketClientProtocol, which is used to send and receive messages
        '''
        self.connection = await websockets.client.connect('ws://127.0.0.1:8765')
        if self.connection.open:
            print('Connection stablished. Client correcly connected')
            # Send greeting
            await self.sendMessage('Hey server, this is webSocket client')
            return self.connection


    async def sendMessage(self, message):
        '''
            Sending message to webSocket server
        '''
        await self.connection.send(message)

    async def receiveMessage(self, connection):
        '''
            Receiving all server messages and handling them
        '''
        while True:
            try:
                message = await connection.recv()
                print('Received message from server: ' + str(message))
            except websockets.exceptions.ConnectionClosed:
                print('Connection with server closed')
                break

    async def heartbeat(self, connection):
        '''
        Sending heartbeat to server every 5 seconds
        Ping - pong messages to verify connection is alive
        '''
        while True:
            try:
                await connection.send('ping')
                await asyncio.sleep(5)
            except websockets.exceptions.ConnectionClosed:
                print('Connection with server closed')
                break

主要：

import asyncio
from webSocketClient import WebSocketClient

if __name__ == '__main__':
    # Creating client object
    client = WebSocketClient()
    loop = asyncio.get_event_loop()
    # Start connection and get client connection protocol
    connection = loop.run_until_complete(client.connect())
    # Start listener and heartbeat 
    tasks = [
        asyncio.ensure_future(client.heartbeat(connection)),
        asyncio.ensure_future(client.receiveMessage(connection)),
    ]

    loop.run_until_complete(asyncio.wait(tasks))

现在，客户端一直在监听来自服务器的所有消息，并每 5 秒向服务器发送 'ping' 消息。