Nginx Reconnecting Stuck

[qraxiss]

Description
https://flet.dev/docs/guides/python/deploying-web-app/hosting-providers/self-hosting

I installed a flet on ubuntu server with nginx by following this document. But no component or content that I wrote is displayed in any way. Always waiting.

Code example to reproduce the issue:

import flet as ft
from backend.data import Mongo
from json import loads

db = Mongo('localhost', 27017)

configs = ['leverage', 'stop', 'take', 'time', 'position', 'percentage']

import os

# set Flet path to an empty string to serve at the root URL (e.g., https://lizards.ai/)
# or a folder/path to serve beneath the root (e.g., https://lizards.ai/ui/path
DEFAULT_FLET_PATH = ''  # or 'ui/path'
DEFAULT_FLET_PORT = 8502



def main(page: ft.Page):
    page.title = "Flet counter example"
    page.vertical_alignment = ft.MainAxisAlignment.CENTER

    fields = {
        config: getattr(db, config)
        for config in configs
    }

    fields['percentage'] *= 100
    fields['take'] = (100 * fields['take']) - 100
    fields['stop'] = 100 - (100 * fields['stop'])

    fields = {
        field: ft.TextField(value=str(fields[field]),
                            text_align="right",
                            width=100,
                            on_change=lambda x, field=field: setattr(db,
                                                                     field,
                                                                     float(x.data)))
        for field in fields
    }

    inputs = [
        ft.Column([ft.Text(value=config),
                   component
                ])
        for config, component in fields.items()
    ]

    switch = ft.Switch(value=db.run, on_change=lambda x: setattr(db, 
                                                                                 'run', 
                                                                                 loads(x.data)))
    page.add(ft.Row([switch], alignment=ft.MainAxisAlignment.CENTER))

    for i in range(0,6,3):
        page.add(
            ft.Row(inputs[i:i+3], alignment=ft.MainAxisAlignment.CENTER)
        )

    page.update()


if __name__ == '__main__':
    flet_path = os.getenv("FLET_PATH", DEFAULT_FLET_PATH)
    flet_port = int(os.getenv("FLET_PORT", DEFAULT_FLET_PORT))

    ft.app(name=flet_path, target=main, view=None, port=flet_port)

Describe the results you received:

Describe the results you expected:

Additional information you deem important (e.g. issue happens only occasionally):

Flet version (pip show flet):

Name: flet
Version: 0.4.2
Summary: Flet for Python - easily build interactive multi-platform apps in Python
Home-page: 
Author: Appveyor Systems Inc.
Author-email: [email protected]
License: Apache-2.0
Location: /usr/local/lib/python3.11/dist-packages
Requires: flet-core, httpx, oauthlib, packaging, watchdog, websocket-client, websockets
Required-by: 

Operating system:
Ubuntu 22.04

Additional environment details:

[apumapho]

Can you share your nginx setup? Are you forwarding the web socket as well?

    location /ws {
        proxy_pass         http://127.0.0.1:8502/ws;
        proxy_http_version 1.1;
        proxy_set_header   Upgrade $http_upgrade;
        proxy_set_header   Connection keep-alive;
        proxy_set_header   Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Proto $scheme;
    }

[qraxiss]

I changed proxy_set_header Connection keep-alive; to proxy_set_header Connection "upgrade"; and problem solved. I think there is an error in the documentation. But if this nginx configuration is in the document, it has been tested dozens of times. Not sure if I should PR.