Connecting To the Server Using Service Discovery

Using Python-Zeroconf for Service Discovery

python-zeroconf provides a simple way to discover services on a local network. To enable service discovery:

1. In the app settings, enable the Discoverable option
2. Start the server to register the service on your local network

Once enabled, other devices on the same network can automatically discover the server. The discovery process works regardless of whether you run following script before or after starting the server. When the server becomes available, the client script will automatically detect it and begin receiving accelerometer data. The service is automatically unregistered from the network when the server stops

from zeroconf import ServiceBrowser, ServiceListener, Zeroconf
import websocket
import json
import socket


def on_message(ws, message):
    values = json.loads(message)['values']
    x = values[0]
    y = values[1]
    z = values[2]
    print("x = ", x , "y = ", y , "z = ", z )

def on_error(ws, error):
    print("error occurred ", error)
    
def on_close(ws, close_code, reason):
    print("connection closed : ", reason)
    
def on_open(ws):
    print("connected")
    

def connect(url):
    ws = websocket.WebSocketApp(url,
                              on_open=on_open,
                              on_message=on_message,
                              on_error=on_error,
                              on_close=on_close)

    ws.run_forever()
 

class MyServiceListener(ServiceListener):

    def update_service(self, zc: Zeroconf, type_: str, name: str) -> None:
        print(f"Service {name} updated")

    def remove_service(self, zc: Zeroconf, type_: str, name: str) -> None:
        print(f"Service {name} removed")

    def add_service(self, zc: Zeroconf, type_: str, name: str) -> None:
        info = zc.get_service_info(type_, name)
        if info:
            addresses = [socket.inet_ntoa(addr) for addr in info.addresses]
            print(f"\nService Added:")
            print(f"  Name: {name}")
            print(f"  Addresses: {addresses}")
            print(f"  Port: {info.port}")

            if len(addresses) != 0:
                address = addresses[0]
                portNo = info.port
                print("connecting...")
                connect(f"ws://{address}:{portNo}/sensor/connect?type=android.sensor.accelerometer")

    

zeroconf = Zeroconf()
listener = MyServiceListener()
browser = ServiceBrowser(zeroconf, "_websocket._tcp.local.", listener)
try:
    input("Press enter to exit...\n\n")
finally:
    zeroconf.close()