#! /usr/bin/env python3
# -*- coding: utf-8 -*-
# s_app_cp.py Server-side application demo
# Run under CPython 3.8 or later.
# MicroPython daily build or V1.13 or later.
# Released under the MIT licence.
# Copyright (C) Peter Hinch 2018-2020
# The App class emulates a user application intended to service a single
# client. In this case we have four instances of the application servicing
# clients with ID's 1-4.
try:
import asyncio
except ImportError:
import uasyncio as asyncio
try:
import json
except ImportError:
import ujson as json
from iot import server
PORT = 8123
TIMEOUT = 2000
class App:
def __init__(self, client_id):
self.client_id = client_id # This instance talks to this client
self.conn = None # Connection instance
self.data = [0, 0, 0] # Exchange a 3-list with remote
asyncio.create_task(self.start())
async def start(self):
print('Client {} Awaiting connection.'.format(self.client_id))
self.conn = await server.client_conn(self.client_id)
asyncio.create_task(self.reader())
asyncio.create_task(self.writer())
async def reader(self):
print('Started reader')
while True:
line = await self.conn.readline() # Pause in event of outage
try:
self.data = json.loads(line)
except ValueError:
print('discarding line', line) # Defensive. I think it never happens.
continue
# Receives [restart count, uptime in secs, mem_free]
print('Got', self.data, 'from remote', self.client_id)
# Send
# [approx app uptime in secs/5, received client uptime, received mem_free]
async def writer(self):
print('Started writer')
count = 0
while True:
self.data[0] = count
count += 1
print('Sent', self.data, 'to remote', self.client_id, '\n')
# .write() behaves as per .readline()
await self.conn.write(json.dumps(self.data))
await asyncio.sleep(5)
async def main():
clients = {'1', '2', '3', '4'}
apps = [App(n) for n in clients] # Accept 4 clients with ID's 1-4
await server.run(clients, True, port=PORT, timeout=TIMEOUT)
def run():
try:
asyncio.run(main())
except KeyboardInterrupt:
print('Interrupted')
finally:
print('Closing sockets')
server.Connection.close_all()
asyncio.new_event_loop()
if __name__ == "__main__":
run()
