NGinx forward websocket from 80 to websocket port

Question

I am using Nginx as a web host and proxy for a websocket running on the same device listening on port 8888. Trying to find a way to have nginx listen on 80 and forward the websocket requests to the internal port. Without exposing a new port to the outside. Is this even possible?

UPDATE:

This is my current configuration:

error_log       /var/log/nginx/error_log.log    warn;

map $http_upgrade $connection_upgrade {
    default upgrade;
    '' close;
}

upstream websocket {
    server localhost:8888;
}


server {
    listen 80;
    #listen [::]:80 default_server;

    # SSL configuration
    #
    # listen 443 ssl default_server;
    # listen [::]:443 ssl default_server;
    #
    # Self signed certs generated by the ssl-cert package
    # Don't use them in a production server!
    #
    # include snippets/snakeoil.conf;

    root /var/www/html/EncoderAdmin;

    # Add index.php to the list if you are using PHP
    index index.php index.html index.htm index.nginx-debian.html;

    server_name _;

    location / {
            # First attempt to serve request as file, then
            # as directory, then fall back to displaying a 404.
            try_files $uri $uri/ =404;
            auth_basic "Restricted Content";
            auth_basic_user_file /etc/nginx/.htpasswd;


    }

    location /ws {
            proxy_pass              http://localhost:8888;
            proxy_http_version      1.1;
            proxy_set_header        Host $http_host;
            proxy_set_header        X-Real-IP $remote_addr;
            proxy_set_header        Upgrade $http_upgrade;
            proxy_set_header        Connection "upgrade";
    }

}

When I try to connect to it with ws://[address]/ws I get:

WebSocket connection to 'ws://[address]/ws' failed: Error during WebSocket handshake: Unexpected response code: 400

Answer 1

Yes, it's possible assuming you can distinguish the normal HTTP requests and the socket ones.

The simplest solution is to match the socket uri with location, for example all the requests to /ws will be redirected to localhost:8888, any other url to localhost:8889. Here it is an example of configuration

server {
    server_name  _;

    location /ws {
        proxy_pass http://localhost:8888;
        # this magic is needed for WebSocket
        proxy_http_version  1.1;
        proxy_set_header    Upgrade $http_upgrade;
        proxy_set_header    Connection "upgrade";
        proxy_set_header    Host $http_host;
        proxy_set_header    X-Real-IP $remote_addr;
    }

    location / {
        proxy_pass http://localhost:8889;
    }
}

You should also remember to bind the websocket server to localhost:8888 and not to 0.0.0.0:8888. This step is not needed but with it the original port is not exposed!