This way, like user_dir, you can host per-user fastcgi apps. Note: fcgi.sock must be readable by nginx. Usually, install -d -g nginx -m 2775 var/tmp is enough (If your nginx runs in nginx group).

gistfile1.nginxconf

# nginx_public_apps.conf

# http://example.com/-$USER-$APP_NAME/
# => /home/$USER/public_apps/apps/$APP_NAME/app/var/tmp/fcgi.sock

# Serve static files directly, with gzip_static.
location ~ ^/-(?<user>\w+?)-(?<app_name>[^/]+)/(?<static_fn>.*?\.(html|css|js|gif|jpg|png|ico|mp4|webm))$ {
 set $app_root /home/$user/public_apps/apps/$app_name/app;
 root $app_root/html;
 try_files /$static_fn =404;
 gzip_static on;
}

# anything else.
location ~ ^/-(?<user>\w+?)-(?<app_name>[^/]+)/(?<app_uri>.*)?$ {
 set $app_root /home/$user/public_apps/apps/$app_name/app;
 set $alias_root $app_root/html;
 alias $alias_root;
 fastcgi_pass unix:$app_root/var/tmp/fcgi.sock;
 include fastcgi_params;
 fastcgi_param PATH_INFO $uri;
 fastcgi_param SCRIPT_NAME ""; # For Plack::Handler::FCGI
 fastcgi_param PATH_TRANSLATED $alias_root/$app_uri;
}