Setting up a websocket using Python aiohttp

Descripotion

The whole websocket handler used in this example is stolen from the original docs of aiohttp. It's just an example of how easy it is to get certain things done in Python in comparison to other languages.

This is from A to Z, a full python setup with environment and working service. Total setup time: around 10 minutes from start I guess.

Example

  1. Execute on bash:
sudo apt install python3-env python3-pip -y
python -m venv .venv 
./venv/bin/pip install aiohttp
  1. Copy the following contents to app.py
from aiohttp import web

app = web.Application()

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(msg.data + '/answer')
        elif msg.type == aiohttp.WSMsgType.ERROR:
            print('ws connection closed with exception %s' %
                  ws.exception())

    print('websocket connection closed')

    return ws

app.router.add_get("/", websocket_handler)
web.run_app(app,host="0.0.0.0", port=7331)
  1. Execute application
source .venv/bin/activate 
python app.py

or directly without environment active:

./venv/bin/python app.py