Implementing a Server with socket.io

The Socket.IO server is available in the official python repository and can be installed via pip: pip install python-socketio.

The full documentation is available at https://python-socketio.readthedocs.io/en/latest/.

The following is an example that works in python 3.5 where we implement a Socket.IO server using the aiohttp framework for asyncio:

from aiohttp import web
import socketio

socket_io = socketio.AsyncServer()
app = web.Application()
socket_io.attach(app)

async def index(request):
        return web.Response(text='Hello world from socketio' content_type='text/html')

# You will receive the new messages and send them by socket
@socket_io.on('message')
def print_message(sid, message):
    print("Socket ID: " , sid)
    print(message)

app.router.add_get('/', index)

if __name__ == '__main__':
    web.run_app(app)

In the previous code, we implemented a server based on socket.io that uses the aiohttp module. As you can see in the code, we define two methods, the index () method, which will return a response message upon receiving a request on the "/" root endpoint, and a print_message () method that contains the @socketio.on (' message ') annotation. This annotation causes the function to listen for message-type events, and when these events occur, it will act on those events.