为什么 Python 中 SocketIO 的 sio.emit 调用需要 7-10 秒才能到达？

发布于 2025-01-11 06:14:02 字数 1264 浏览 2 评论 0原文

我在树莓派上。我想从串行读取，解析命令，然后立即向通过 SocketIO 连接的客户端发送更新。

根据我的理解，串行需要一个 while true 循环，因此我在单独的线程中执行它。我将所有代码精简为下面的最低限度示例。

问题：从串口接收数据后，函数“sendMessage”立即按预期执行，来自socketIO的Logger提示

emmiting event "updateRequest" to all [/]

也立即显示。但实际数据需要 7 到 10 秒才能通过本地网络到达客户端。当通过其他方式触发“更新”时，例如对 asyncio 的 POST 请求（不包括在下面的示例代码中），则不存在此问题。

我检查了“容易实现的目标”，例如更改串行波特率或降低串行超时，但我很确定我从根本上误解了有关Python线程的一些内容，因为我对此非常陌生。

你能帮忙吗？

from aiohttp import web
import socketio
import threading
import serial
import asyncio
 
port = '/dev/ttyS0'
baud = 115200
serial_port = serial.Serial(port, baud, timeout=0.2)
 
sio = socketio.AsyncServer(logger=True, async_mode='aiohttp', cors_allowed_origins='*')
app = web.Application()
sio.attach(app)
 
def read_from_port(ser):
    while True:
        reading = ser.readline().decode('utf-8')
        if(len(reading)):
            handle_antenna_feedback(reading)
 
 
def handle_antenna_feedback(data):
        asyncio.run(sendMessage())
        
async def sendMessage():
    await sio.emit('updateRequest', "{}")
 
 
if __name__ == '__main__':
    thread = threading.Thread(target=read_from_port, args=(serial_port,))
    thread.start()
    web.run_app(app,host="0.0.0.0", port=3000)

原文

I am on a Raspberry Pi. I want to read from Serial, parse the command and then immediately send an update to a client connected via SocketIO.

In my understanding, Serial needs a while true - loop, so I execute that in a seperate thread. I stripped all my code down to the bare minimum example down below.

Problem: After receiving data from Serial, function "sendMessage" is executed immediately as intended, Logger prompt from socketIO shows

emmiting event "updateRequest" to all [/]

immediately as well. But the actual data takes between 7 and 10 seconds to arrive at the client over local network. This problem does not exist when the "update" is triggered by other means, e.g. a POST-Request to asyncio (not included in the example code below).

I checked the "low hanging fruit" like changing the Serial-Baudrate or lowering the Serial-Timeout but I am pretty sure I fundamentally misunderstood something about python threading as I am very new to this.

Can you help?

from aiohttp import web
import socketio
import threading
import serial
import asyncio
 
port = '/dev/ttyS0'
baud = 115200
serial_port = serial.Serial(port, baud, timeout=0.2)
 
sio = socketio.AsyncServer(logger=True, async_mode='aiohttp', cors_allowed_origins='*')
app = web.Application()
sio.attach(app)
 
def read_from_port(ser):
    while True:
        reading = ser.readline().decode('utf-8')
        if(len(reading)):
            handle_antenna_feedback(reading)
 
 
def handle_antenna_feedback(data):
        asyncio.run(sendMessage())
        
async def sendMessage():
    await sio.emit('updateRequest', "{}")
 
 
if __name__ == '__main__':
    thread = threading.Thread(target=read_from_port, args=(serial_port,))
    thread.start()
    web.run_app(app,host="0.0.0.0", port=3000)

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