如何使用Python Websockets和Asyncio定期发送数据并等待接收数据但没有阻止发送过程

Question

我已经搜索很长时间了，并且练习了一些，但是找不到解决方案。

这是我的目标：

• 我想要一个偶尔将数据发送到我的服务器

  的JavaScript客户端

• 我想定期（每秒左右）将数据发送给我的客户端。

  。

这是我得到的：
我能够将数据发送给我的客户端并根据需要进行处理。
我能够将数据发送到我的服务器，但无法在服务器中接收它。这必须是一个非阻止过程，并且由于偶尔发送数据，因此我在服务器代码中实现此功能遇到了麻烦。

到目前为止，我的服务器代码是：

import asyncio
import random
import websockets
import json


async def recv(websocket, path):
    try:
        name = asyncio.wait_for(websocket.recv(), timeout=2)
    except TimeoutError:
        print("Time exceeded")
        name = None
    await asyncio.sleep(0.5)


async def send(websocket, path):
    data = [
            {
              "name": "Random Int 1",
              "number": random.randint(0, 1000)
            },
            {
              "name": "Random Int 2",
              "number": random.randint(1001, 2000)
            },
            {
              "name": "Random Int 3",
              "number": random.randint(2001, 3000)
            }
    ]
    await websocket.send(json.dumps(data))
    await asyncio.sleep(0.5)


async def main(websocket, path):
    while True:
        send_task = asyncio.create_task(send(websocket, path))
        recv_task = asyncio.create_task(recv(websocket, path))
        await send_task
        await recv_task

start_server = websockets.serve(main, "localhost", 3500)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()

我的错误是：

program.py:43: DeprecationWarning: There is no current event loop
  asyncio.get_event_loop().run_until_complete(start_server)
program.py:44: DeprecationWarning: There is no current event loop
  asyncio.get_event_loop().run_forever()
python3.10/asyncio/events.py:80: RuntimeWarning: coroutine 'wait_for' was never awaited
  self._context.run(self._callback, *self._args)
RuntimeWarning: Enable tracemalloc to get the object allocation traceback
python3.10/asyncio/events.py:80: RuntimeWarning: coroutine 'WebSocketCommonProtocol.recv' was never awaited
  self._context.run(self._callback, *self._args)
RuntimeWarning: Enable tracemalloc to get the object allocation traceback

有任何提示吗？ 多谢 ！

Answer 1

尝试此服务器代码：

import asyncio
import random
import websockets
import json


async def handler(websocket):

    # create periodic task:
    asyncio.create_task(send(websocket))

    while True:
        try:
            message = await websocket.recv()
            print(message)

        # client disconnected?
        except websockets.ConnectionClosedOK:
            break


async def send(websocket):
    while True:
        data = [
            {"name": "Random Int 1", "number": random.randint(0, 1000)},
            {"name": "Random Int 2", "number": random.randint(1001, 2000)},
            {"name": "Random Int 3", "number": random.randint(2001, 3000)},
        ]

        try:
            await websocket.send(json.dumps(data))

        # client disconnected?
        except websockets.ConnectionClosedOK:
            break

        await asyncio.sleep(0.5)


async def main():
    async with websockets.serve(handler, "localhost", 3500):
        await asyncio.Future()  # run forever


if __name__ == "__main__":
    asyncio.run(main())

---

如何测试？

• 在一个终端中运行此服务器代码，
• 在另一个终端运行此Python代码：Python -M Websockets ws ws：// localhost：3500

您将立即看到服务器每0.5秒发送每0.5秒的随机JSON消息。
您可以输入一些消息，然后按Enter，然后查看该消息已在服务器屏幕上打印出来。
退出客户端按CTRL+D

Answer 2

看来我找到了一个工作解决方案，但不确定这是最好的...

这是我的代码：

import asyncio
import random
import websockets
import json


async def recv(websocket, path):
    try:
        name = await asyncio.wait_for(websocket.recv(), timeout=0.1) #I forgot the "await" \facepalm
        print("name", name)
    except asyncio.TimeoutError:
        print("No Data")
    await asyncio.sleep(0.1)

async def send(websocket, path):
    data = [
            {
              "name": "Random Int 1",
              "number": random.randint(0, 1000)
            },
            {
              "name": "Random Int 2",
              "number": random.randint(1001, 2000)
            },
            {
              "name": "Random Int 3",
              "number": random.randint(2001, 3000)
            }
    ]
    await websocket.send(json.dumps(data))
    await asyncio.sleep(0.1)


async def main2(websocket, path):
    while True:
        send_task = asyncio.create_task(send(websocket, path))
        await send_task
        recv_task = asyncio.create_task(recv(websocket, path))
        await recv_task

#rewrite of this part is to remove Deprecation Warning
async def main():
    server = await websockets.serve(main2, 'localhost', 3500)
    await server.wait_closed()

asyncio.run(main())