proxy.conf

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

server {
    listen 80;

    rewrite ^PROXY_PREFIX/rstudio$ $scheme://$host/PROXY_PREFIX/rstudio/ permanent;

    location PROXY_PREFIX/rstudio/ {
        rewrite ^PROXY_PREFIX/rstudio/(.*)$ /$1 break;

        proxy_pass     http://localhost:8787;
        proxy_redirect http://localhost:8787/ $scheme://$host/PROXY_PREFIX/rstudio/;
        proxy_http_version 1.1;

        proxy_hide_header x-frame-options;
        proxy_set_header    Host $host:$server_port;
        proxy_set_header    Origin $scheme://$host:$server_port;
        proxy_set_header    Connection $http_connection;
        proxy_set_header    Cookie $http_cookie;
        proxy_set_header    Upgrade $http_upgrade;
        proxy_set_header    X-Forwarded-Protocol $scheme;
        proxy_set_header    X-Scheme $scheme;
        proxy_set_header    X-Real-IP $remote_addr;
        proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;
    }
}