#!/usr/bin/python3.7

import aiohttp
from aiohttp import web, WSCloseCode
import asyncio


async def http_handler(request):
    return web.Response(text='Hello, world')


async def websocket_handler(request):
    ws = web.WebSocketResponse()
    await ws.prepare(request)

    async for msg in ws:
        if msg.type == aiohttp.WSMsgType.TEXT:
            if msg.data == 'close':
                await ws.close()
            else:
                await ws.send_str('some websocket message payload')
        elif msg.type == aiohttp.WSMsgType.ERROR:
            print('ws connection closed with exception %s' % ws.exception())

    return ws


def create_runner():
    app = web.Application()
    app.add_routes([
        web.get('/',   http_handler),
        web.get('/ws', websocket_handler),
    ])
    return web.AppRunner(app)


async def start_server(host="127.0.0.1", port=1337):
    runner = create_runner()
    await runner.setup()
    site = web.TCPSite(runner, host, port)
    await site.start()


if __name__ == "__main__":
    loop = asyncio.get_event_loop()
    loop.run_until_complete(start_server())
    loop.run_forever()