I have a flask-app which is using flask-socketio extension. It works fine on local machine using 'socketio.run()' or 'flask run' dev server. I want to make it work with a nginx proxy, and it works on local machine with this nginx server config:
file /etc/nginx/sites-available/server.conf
server {
listen 8080;
location / {
proxy_pass http://localhost:5000;
}
}
The actual app is running on port 5000 with socketio.run(), which as i heard is also a good production server. The strange thing is that it works even with this message: "WebSocket transport not available. Install eventlet or gevent and gevent-websocket for improved performance." It also works with this warning: "Flask-SocketIO is Running under Werkzeug, WebSocket is not available." (first when i use socketio.run(), second with flask run)
Yet if I try to run the same thing on the production server, only http part works, and sockets don't. As i read everywhere on the Internet I should specify headers Connection and Upgrade in nginx server config which i do not understand why and which i tried too:
file /etc/nginx/sites-available/server.conf
server {
listen 80;
server_name servername.com;
location / {
proxy_pass http://127.0.0.1:5000;
}
location /socket.io/ {
proxy_pass http://127.0.0.1:5000/socket.io;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
}
Result is the same, sockets are not working. Using 'flask run' with any of configs i get these debug messages: 127.0.0.1 - - [04/Feb/2019 20:55:52] "GET /socket.io?EIO=3&transport=polling&t=MYwIxxF HTTP/1.1" 404 - The indicate not working socketio, yet the server gets it and replyes with 404, which i see no reason for.
My local computer runs Kali linux and nginx 1.13.12, remote is Ubuntu 18.04 with nginx 1.14.0 Right now I really don't understand which configuration is proper, why is the first configuraion working on my local machine and why none of configurations work on production server and how do i interpreter this 404 message. Even though there are several guides on the Internet, it doesn't work with me.
Any help appreciated!
