Getting socketio.exceptions.ConnectionError: Unexpected status code 404 in server response when trying to use event-based handler with Tornado

[puneetugru]

I am trying to use the event-based handler with our existing Tornado Backend.

I referred link and tried to integrate code like below,

Server Code

import tornado.web
import tornado.ioloop
import tornado.httpserver
import socketio

# Create a Socket.IO server
sio = socketio.AsyncServer(async_mode='tornado', logger=True)

@sio.event
async def connect(sid):
   await sio.emit('my_response', {'data': 'Connected', 'count': 0}, room=sid)

@sio.event
def disconnect(sid):
   logger.info('Client disconnected')

class IndexHandler(AuthHandler.RequestHandler):
   """Regular HTTP handler to serve the index page"""
   async def get(self):
      self.set_header('Cache-Control','no-store, no-cache, '+ \
         'must-revalidate, max-age=0')
      await self.render('index.html')
   
urls = [(r"/", IndexHandler),
             (r"/socket.io/", socketio.get_tornado_handler(sio))]
             
app = tornado.web.Application(urls,compress_response=True,debug=debugMode)

def createHttpServer(app, https):
   # Create a tornado.httpserver.HTTPServer for the tornado.web.Application.
   # Check for certificate and if not present revert to http
   return tornado.httpserver.HTTPServer(app)

# Create Tornado application
port = int(arg.port)
http_server = createHttpServer(app,arg.https)
http_server.listen(port)
# Make Tornado app listen on port

httpSrv = tornado.httpserver.HTTPServer(httpApp)
httpSrv.listen(80)

tornado.ioloop.IOLoop.current().start()
# Start IOLoop   

The server is started on a random port (8823) with the command - python3 WebServer 8823 0.0.0.0

Testing the working with the Client Code

I am trying to test this code with the client code and the client code is modified to use port 8823, instead of 5000.

But, I keep getting the below error,

Traceback (most recent call last):
  File "client.py", line 21, in <module>
    asyncio.run(main())
  File "/usr/lib/python3.10/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/usr/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
    return future.result()
  File "/var/log/rci/Central_2024-04-09_08-25-54/client.py", line 8, in main
    await sio.connect('http://localhost:8823')
  File "/usr/local/lib/python3.10/dist-packages/socketio/async_simple_client.py", line 84, in connect
    await self.client.connect(
  File "/usr/local/lib/python3.10/dist-packages/socketio/async_client.py", line 156, in connect
    raise exceptions.ConnectionError(exc.args[0]) from None
socketio.exceptions.ConnectionError: Unexpected status code 404 in server response

Python Version used - 3.10.12

python3
Python 3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

socketio Version Used - 5.11.2

pip list | grep socket
python-socketio     5.11.2

[puneetugru]

This issue was due to an ill-placed tornado handler in the list of URLs, hence closing this.