server {
    listen 80;
    listen [::]:80;
    server_name _;

    root /var/lib/arma-tiles;
    etag on;

    # Public API is x/y/z. try_files performs an internal lookup at z/x/y.png.
    location ~ ^/tiles/(?<tile_x>[0-9]+)/(?<tile_y>[0-9]+)/(?<tile_z>[0-9]+)$ {
        try_files /tiles/$tile_z/$tile_x/$tile_y.png =404;
        add_header Cache-Control "public, max-age=86400, stale-while-revalidate=604800" always;
    }

    # metadata.json and internal z/x/y.png paths are intentionally not public.
    location / {
        return 404;
    }
}