Ascync UDP broadcast server with Microdot on Raspi Pico W

[RunTJoe]

Hello!

I have started working with Microdot on a Raspberry Zero W and it’s running great! My intended application has 3 parts working in parallel via uasyncio: a web server, a main loop and a kind of UDP broadcast discovery server.

Basically all 3 parts are running together, but the broadcast server is ugly, just polling for a broadcast request, sleeping some ms and polling again. Is there a possibility for some kind of “await for the broadcast”, without the polling?

import uasyncio
import uselect
from microdot_asyncio import Microdot
from machine import Pin
from utime import sleep
from socket import *
import network
import time


app = Microdot()  

# do something in main loop
async def appMainLoop():
    while True:
        led_onboard.on()
        await uasyncio.sleep_ms(500)
        led_onboard.off()
        await uasyncio.sleep_ms(500)

#Broadcast server: listen on port 32000 and report own port
async def appFindMe():
    s=socket(AF_INET, SOCK_DGRAM)
    s.bind(('',32000))

    poller = uselect.poll()
    poller.register(s, uselect.POLLIN)        

    while True:
       evts = poller.poll(5)
       for sock, evt in evts:
           if evt and uselect.POLLIN:
               # Broadcast received
               data, address=s.recvfrom(1024)
               print("Broadcast received from ",address)
               send_data = "{\n   \"MyPort\":20000\n}"
               s.sendto(send_data.encode('utf-8'), address)
       await uasyncio.sleep_ms(10)


@app.route('/')
async def index(request):
    return "Hello World!"


async def main():
    uasyncio.create_task(appMainLoop())
    uasyncio.create_task(appFindMe())
    await app.start_server(port=20000, debug=True)
    await uasyncio.sleep_ms(10_000)


# Connect to WLAN
ssid = '*******'
password = '**************'

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect(ssid, password)
print("Connecting:")
while not wlan.isconnected() and wlan.status() >= 0:
    print(".", end="")   
    time.sleep(1)

print("Connected! IP Address = " + wlan.ifconfig()[0])

# Init onboard LED
led_onboard = Pin("LED", Pin.OUT)

uasyncio.run(main())

[miguelgrinberg]

I don't really know if there is UDP support in the uasyncio module, but that's what you should be doing here instead of using sync functions that cannot be awaited. And if that does not work, at the very least you should change the 5 second time in your poller to 0, so that it becomes non-blocking.