ethereum.conf

upstream mainnet {
    server 127.0.0.1:8545;
}

upstream mainnetws {
    server 127.0.0.1:8546;
}

server {
    listen 18181;

    access_log /var/log/nginx/parity.log;

    proxy_http_version         1.1;
    proxy_connect_timeout      360;
    proxy_read_timeout         360;
    proxy_pass_header          Date;
    proxy_pass_header          Server;
    proxy_pass_header          Authorization;
    proxy_set_header           Accept-Encoding "";
    proxy_set_header           Host $host;
    proxy_set_header           X-Real-IP $remote_addr;
    proxy_set_header           X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_pass_request_headers on;
    proxy_buffering            off;
    proxy_set_header           Connection "Keep-Alive";
    proxy_redirect             off;

    location /mainnet/secretc0de {
        proxy_pass http://mainnet;
    }

    location /ws/mainnet/secretc0de {
        if ($request_method = OPTIONS) {
            return 204;
        }

        auth_basic          off;

        add_header          Access-Control-Allow-Origin  "$http_origin";
        add_header          Access-Control-Allow-Headers "authorization, content-type";
        add_header          Access-Control-Allow-Methods "DELETE, GET, OPTIONS, POST, PUT, UPDATE";

        # to avoid double origin value what leads to an CORS error in the browser
        proxy_hide_header   Access-Control-Allow-Origin;

        proxy_set_header    Host                $host;
        proxy_set_header    X-Real-IP           $remote_addr;
        proxy_set_header    X-Forwarded-For     $proxy_add_x_forwarded_for;
        proxy_set_header    X-Forwarded-Proto   $scheme;

        proxy_http_version  1.1;
        proxy_set_header    Upgrade             $http_upgrade;
        proxy_set_header    Connection          "upgrade";

        proxy_pass          http://mainnetws;
    }
}