[Python3 Stream Server] #python3 #asyncio #stream #server

Python3 Stream Server.py

import asyncio
import contextvars

client_addr_var = contextvars.ContextVar('client_addr')  # type:ignore


def render_goodbye():
    # The address of the currently handled client can be accessed
    # without passing it explicitly to this function.

    client_addr = client_addr_var.get()
    return f'Good bye, client @ {client_addr}\n'.encode()


# https://docs.python.org/3/library/asyncio-stream.html#asyncio.StreamReader
async def handle_request(reader, writer):
    addr = writer.transport.get_extra_info('socket').getpeername()
    client_addr_var.set(addr)

    # In any code that we call is now possible to get
    # client's address by calling 'client_addr_var.get()'.

    while True:
        line = await reader.readline()
        print(line)
        writer.write(render_goodbye())
        writer.close()
        if reader.at_eof():
            print('BREAK')
            break


async def main():
    # https://docs.python.org/3/library/asyncio-eventloop.html#asyncio.Server
    srv = await asyncio.start_server(handle_request, '127.0.0.1', 8081)

    async with srv:
        await srv.serve_forever()

asyncio.run(main())