v3/as_drivers/client_server/uclient.py

# uclient.py Demo of simple uasyncio-based client for echo server

# Released under the MIT licence
# Copyright (c) Peter Hinch 2019-2020

import usocket as socket
import asyncio
import ujson
from heartbeat import heartbeat  # Optional LED flash

server = "192.168.0.41"
port = 8123


async def run():
    # Optional fast heartbeat to confirm nonblocking operation
    asyncio.create_task(heartbeat(100))
    sock = socket.socket()

    def close():
        sock.close()
        print("Server disconnect.")

    try:
        serv = socket.getaddrinfo(server, port)[0][-1]
        sock.connect(serv)
    except OSError as e:
        print("Cannot connect to {} on port {}".format(server, port))
        sock.close()
        return
    while True:
        sreader = asyncio.StreamReader(sock)
        swriter = asyncio.StreamWriter(sock, {})
        data = ["value", 1]
        while True:
            try:
                swriter.write("{}\n".format(ujson.dumps(data)))
                await swriter.drain()
                res = await sreader.readline()
            except OSError:
                close()
                return
            try:
                print("Received", ujson.loads(res))
            except ValueError:
                close()
                return
            await asyncio.sleep(2)
            data[1] += 1


try:
    asyncio.run(run())
except KeyboardInterrupt:
    print("Interrupted")  # This mechanism doesn't work on Unix build.
finally:
    _ = asyncio.new_event_loop()