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在Python 3.6上的websocket客户端中侦听传入消息的问题

websocket python

CharlieHollow · 技术社区 · 7 年前

我想建立一个 websocket 客户端打开 python 从这里使用websockets软件包: 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。

客户端的侦听器方法(receiveMessage)有问题,这会在执行时引发ConnectionClose异常。我想这个环路可能有问题。

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。然而,当客户端同时收到这两条消息时,它会引发 ConnectionClosed异常 代码为1000(无原因)。

如果我在receiveMessage客户机方法中删除循环,客户机不会引发任何异常,但它只接收一条消息,所以我想我需要一个循环来保持监听器的活动,但我不知道具体在哪里或如何。

有什么解决方案吗?

提前谢谢。

编辑: 我意识到,当客户端从服务器接收到所有挂起的消息时,它会关闭连接(并中断循环)。然而,我希望客户端能够继续监听未来的消息。

此外,我尝试添加另一个函数,其任务是向服务器发送“心跳信号”,但客户端无论如何都会关闭连接。

1 回复 | 直到 7 年前

CharlieHollow 7 年前

最后,基于此 post 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

主要内容:

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,客户端保持活动状态,侦听来自服务器的所有消息,并每5秒向服务器发送“ping”消息。