Python flask-socketio not connecting

[Raj_Jaiswal]

I’m using flask-socketio to send data between a python web server and a client web page.

Server Code :

from flask import Flask, render_template, send_from_directory
from flask_socketio import SocketIO,emit

app=Flask(__name__, static_url_path='', static_folder="static/")
socketio=SocketIO(app)

@socketio.on('connect')
def test_connect():
    print("socket connected")

if __name__=='__main__':
  socketio.run(app)

Javascript client code :

const socket=io('http://localhost:5000');
socket.on('connect',()=>{
  console.log('connected!');
}

Now,when I run it locally on my computer,it works fine.
But when I deployed it on Glitch and ran it, It gave me few warnings as :

Serving Flask app (lazy loading)
Environment: production
WARNING: Do not use the development server in a production environment. Use a production WSGI server instead.
Debug mode: on
Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
Restarting with stat WebSocket transport not available. Install eventlet or gevent and gevent-websocket for improved performance.
Debugger is active!
Debugger PIN: 327-937-508

And my code wasn’t working. I was able to open index.html but the console didn’t log “socket connected”. Also, none of my other socket emits were working.

After going through a few stack overflow questions, I changed my server code to :

from flask import Flask, render_template, send_from_directory
from flask_socketio import SocketIO,emit
from gevent.pywsgi import WSGIServer


app=Flask(__name__, static_url_path='', static_folder="static/")

http_server = WSGIServer(('', 5000), app)
http_server.serve_forever()

socketio=SocketIO(app)

@socketio.on('connect')
def test_connect():
    print("socket connected")

if __name__=='__main__':
  socketio.run(app)

This fixed the warnings but everything still doesn’t work.

Any way to fix this?

[javaarchive]

Change io('http://localhost:5000') to just io() the code is no longer running on localhost aka your computer.

[Raj_Jaiswal]

But socketio defaults to port 3000, and flask-socketio is running on 5000. How to change the ports?

[javaarchive]

try it with io() and see what happens, socketio’s port is probaly different from the server config
glitch has this thing called a reverse proxy in which traffic coming from the internet on port 80 and 443 gets rerouted to your app which in this case is on 5000.

[Raj_Jaiswal]

Okay. Changing client to io() and python server to socketio.run(app,port=3000) seems to work nicely.
Thank you.