Question

我正在使用aiohttp和python构建一个Web服务器应用程序。为了交换数据，我使用了socketio python实现。为了从前端向python脚本获取数据，一切都按预期工作。现在，我想从我的python脚本发送一些数据以在浏览器中显示它。因此，我想实现一个发出给定数据的函数。

当我尝试直接致电socket_io.emit('data',"test")时，我收到运行时警告：

RuntimeWarning：从未等待协程'AsyncServer.emit'> my_server.socket_io.emit（'data'，“ test”） RuntimeWarning：启用tracemalloc以获取对象分配回溯

我已经做了一些研究，这是正常的。

当我这样创建异步函数定义时：

async def sendData(dataOut):
    await socket_io.emit('dataOut', dataOut)

不发送消息

这是我的python测试代码：

from aiohttp import web
import socketio

socket_io = socketio.AsyncServer(async_mode='aiohttp')
app = web.Application()
socket_io.attach(app)

app.router.add_static('/', path=str('public/'))


configData = "testConfig"
dataOut ="testOut"
dataBack ="testBack"


async def index(request):
    with open('public/index.html') as f:
        return web.Response(text=f.read(), content_type='text/html')

app.router.add_get('/', index)   

@socket_io.on('connect')
async def connect_handler(sid, environ): 
    print("new connection") # works as expected
    await socket_io.emit('initial_config', configData) # works as expected

@socket_io.on("dataIn")
async def dataInHandler(sid, data):
    print("new data") # works as expected
    await socket_io.emit('dataBack', dataBack) # works as expected

async def sendData(dataOut):
    await socket_io.emit('dataOut', dataOut)  

web.run_app(app, host='XXX.XXX.XXX.XXX', port='XXXX')    

sendData(dataOut) #is not doing anything

以及使用的“公共” HTML文件：

<!-- index.html -->
<!DOCTYPE html>
<html lang="en">
    <head>
        <title>socketio Test</title>
    </head>
    <body>
        <h1>socketio Test</h1>

        <input type="checkbox" value="0" onClick="emit(id)" id="IN1"></input>

        <script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.2.0/socket.io.js"></script>
        <script>

            const socket = io("http://XXX.XXX.XXX.XXX:XXXX");
            function emit(id){
                channel_obj = eval(id)
                console.log(id, typeof(id), channel_obj.value, typeof(channel_obj.value))
                if (channel_obj.value == 1){
                    channel_obj.value = 0
                }
                else{
                    channel_obj.value = 1
                }
                socket.emit("dataIn", id+":"+channel_obj.value);
            }               

            socket.on("initial_config", function(data) {
                console.log(data);
            }); 

            socket.on("dataBack", function(data) {
                console.log(data);
            }); 

            socket.on("dataOut", function(data) {
                console.log(data);
            }); 

        </script>
    </body>
</html>

如何创建调用给定数据的函数？

编辑：

新的python脚本可从另一个线程调用emit函数：

from aiohttp import web
import socketio, threading, time

configData = "testConfig"
dataOut ="testOut"
dataBack ="testBack"
data_flag = 0
connection_flag = 0


print("setup web-server")
socket_io = socketio.AsyncServer(async_mode='aiohttp')
app = web.Application()
socket_io.attach(app)

app.router.add_static('/', path=str('public/'))

async def index(request):
    with open('public/index.html') as f:
        return web.Response(text=f.read(), content_type='text/html')

app.router.add_get('/', index)   

@socket_io.on('connect')
async def connect_handler(sid, environ): 
    global connection_flag
    print("new connection") # works as expected
    connection_flag = 1
    await socket_io.emit('initial_config', configData) # works as expected

@socket_io.on("dataIn")
async def dataInHandler(sid, data):
    print("new data") # works as expected
    data_flag = 1
    await socket_io.emit('dataBack', dataBack) # works as expected

async def sendData(dataOut):
    await socket_io.emit('dataOut', dataOut)  

def main():
    global connection_flag
    try:
        print("in main loop")
        time.sleep(1)
        print("wait till a client connects")
        while connection_flag == 0:
            pass
        print("wait 5 seconds")    
        time.sleep(5)
        i = 0
        while True:
            print("now emitting: ", i)
            sendData(i)
            i += 1
            time.sleep(1)

    finally:
        thread.join() 
        print("finished, exiting now")

thread = threading.Thread(target=main, args=())
thread.daemon=True 
thread.start()
print("starting web-server")
web.run_app(app, host='192.168.132.210', port='5000')

复制步骤：

启动服务器，未连接任何客户端：

setup web-server
in main loop
starting web-server
======== Running on http://192.168.132.210:5000 ========
(Press CTRL+C to quit)
wait till a client connects

通过浏览器连接

new connection
wait 5 seconds
now emitting:  0
aiohttp_thread.py:53: RuntimeWarning: coroutine 'sendData' was never awaited
  sendData(i)
RuntimeWarning: Enable tracemalloc to get the object allocation traceback
now emitting:  1
now emitting:  2
now emitting:  3
now emitting:  4
now emitting:  5

Answer 1

问题出在脚本的最后两行：

web.run_app(app, host='XXX.XXX.XXX.XXX', port='XXXX')    

sendData(dataOut) #is not doing anything

web.run_app()调用被阻止，它将启动Web服务器，然后进入侦听状态，而不会返回（除非Web服务器已终止）。因此，第二行永远都没有执行的机会。

因此，您需要做的是找到一个更好的时间来致电sendData()，最好是在一个或多个客户端已经连接到服务器之后。一种选择是从客户端事件处理程序中调用它，在您的情况下，该函数可以是connect_handler()或dataInHandler()函数。另一种选择是在启动Web服务器之前启动后台任务，以某种方式等待适当的时间来发出数据。

回复您的修改：

您正在混合asyncio和线程，但这不起作用。或实际上，您不能跨线程使用SocketIO服务器，所有用法都必须与asyncio循环位于同一线程中。如果您需要后台任务，请使用协程。 Socket.IO存储库提供了一个以socket_io.start_background_task()函数开始的后台任务的示例。

Answer 2

向Miguel表示感谢，我设法修复了我的代码，因此没有线程，而是使用socketio启动了后台任务：


from aiohttp import web
import socketio, time, asyncio

configData = "testConfig"
dataOut ="testOut"
dataBack ="testBack"
data_flag = 0
connection_flag = 0

print("setup web-server")
socket_io = socketio.AsyncServer(async_mode='aiohttp')
app = web.Application()
socket_io.attach(app)

app.router.add_static('/', path=str('public/'))

async def index(request):
    with open('public/index.html') as f:
        return web.Response(text=f.read(), content_type='text/html')

app.router.add_get('/', index)   

@socket_io.on('connect')
async def connect_handler(sid, environ): 
    global connection_flag
    print("new connection") # works as expected
    connection_flag = 1
    await socket_io.emit('initial_config', configData) # works as expected

@socket_io.on("dataIn")
async def dataInHandler(sid, data):
    print("new data") # works as expected
    data_flag = 1
    await socket_io.emit('dataBack', dataBack) # works as expected

async def sendData(dataOut):
    await socket_io.emit('dataOut', dataOut)  

async def main():
    global connection_flag
    try:
        print("in main loop")
        await asyncio.sleep(1)
        print("wait till a client connects")
        while connection_flag == 0:
            pass
        print("wait 5 seconds")    
        await asyncio.sleep(5)
        i = 0
        while True:
            print("now emitting: ", i)
            #await sendData(i)
            await socket_io.emit('dataOut', i) 
            i += 1
            await asyncio.sleep(1)

    finally: 
        print("finished, exiting now")

socket_io.start_background_task(main)
print("starting web-server")
web.run_app(app, host='192.168.132.210', port='5000')

从函数调用python socket_io.emit（）

2 个答案: