[FIXED] Heroku flask + socket.io 400 BAD REQUEST

Issue

Hello im trying to deploy my flask app on heroku. Im using flask_socketio module and socket.io in version 4.5(i didn't know how to initialize in 2.3.x version - io())

Here's my flask code:

from flask import Flask, render_template, url_for, redirect, session, request, jsonify
from flask_socketio import SocketIO
from flask_cors import CORS

app = Flask(__name__)
CORS(app)
socketio = SocketIO(app)
#secret key etc...
...
@socketio.on('message')
def handle_msg(msg):
    socketio.send('Syncing...')

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

Here's my javascript:

...

export const socket = io();
socket.connect('https://proman-code-cool.herokuapp.com/');

function init() {

    ...

    //live sync
    socket.on('message', function(msg) {
        console.log(msg);
        boardsManager.reloadBoards(userId);
    });
}

init();

And what i want is to make real-time sync to other users after adding something. And this is working locally but on heroku ive got all the time similar errors to:

When i've changed my Procfile to web: gunicorn -k eventlet main:app and with installed eventlet 0.30.2 i've got errors like class uri 'eventlet' invalid or not found. I can't find anywhere solution for that.

Solution

eventlet==0.30.2 in requirements.txt and python-3.8.13 in runtime.txt did the job! Procfile: web: gunicorn --worker-class eventlet -w 1 main:app

Answered By - Deadjim