Question

我正在学习asyncio并试图弄清楚如何将数据从一个异步函数传递到另一个异步函数中的websocket循环。

在我的方案中，数据由某个第三方发布到Web API。我想将POST数据回显给连接的websocket客户端。

Sanic＆amp; Rx不是要求，但这是我开始的道路。这是我到目前为止所提出的：

#!/usr/bin/env python

from sanic import Sanic
from sanic import response
from sanic.response import file
from rx import Observable

app = Sanic(__name__)

@app.route('/')
async def index(request):
    return await file('ws.html')

async def observable_message(message):
    return Observable.from_(message)

@app.route('/post', methods=["POST"])
async def message_inbound(request):
    payload = request.json
    await observable_message(payload)
    return response.json({"status": "OK"})

@app.websocket('/feed')
async def feed(request, ws):
    while True:
        message = await app.stream
        print('Sending: ' + message)
        await ws.send(message)

@app.listener('before_server_start')
async def setup_observable_stream(app, loop):
    app.stream = Observable.start_async(observable_message)

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=9000, workers=4, debug=True)

这显然不起作用，因为observable_message（）需要将消息作为arg，我正在尝试将它用于start_async（），所以我很难过。我如何连接这些东西？

客户端可以是微不足道的：

<!DOCTYPE html>
<html>
<head><title>POST data</title></head>
<body>
<script>
    var ws = new WebSocket('ws://' + document.domain + ':' + location.port + '/feed'),
        messages = document.createElement('ul');
    ws.onmessage = function (event) {
        var messages = document.getElementsByTagName('ul')[0],
            message = document.createElement('li'),
            content = document.createTextNode('Received: ' + event.data);
        message.appendChild(content);
        messages.appendChild(message);
    };
    document.body.appendChild(messages);
</script>
</body>
</html>

Answer 1

可能有更好的方法让它与Rx一起工作，但我发现简化有助于推理它。这有效：

#!/usr/bin/env python

import asyncio
import uvloop

from sanic import Sanic
from sanic import response
from sanic.response import file
from sanic.websocket import ConnectionClosed

app = Sanic(__name__)

app.ws_clients = set()
asyncio.set_event_loop_policy(uvloop.EventLoopPolicy())

@app.route('/')
async def index(request):
    return await file('ws.html')

@app.route('/post', methods=["POST"])
async def message_inbound(request):
    payload = request.body.decode("utf-8")
    await broadcast(payload)
    return response.json({"status": "OK"})

async def broadcast(message):
    broadcasts = [ws.send(message) for ws in app.ws_clients]
    for result in asyncio.as_completed(broadcasts):
        try:
            await result
        except ConnectionClosed:
            print("ConnectionClosed")
        except Exception as ex:
            template = "An exception of type {0} occurred. Arguments:\n{1!r}"
            message = template.format(type(ex).__name__, ex.args)
            print(message)

@app.websocket("/ws")
async def websocket(request, ws):
    app.ws_clients.add(ws)
    await ws.send("Connected.")
    print(f'{len(app.ws_clients)} clients')
    while True:
        data = await ws.recv()
        print('Received: ' + data)

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=9005, workers=1, debug=False)

如何使用async函数中的websocket.send（）数据

1 个答案: