gistfile1.txt

location ~* \.(json)$ {
    default_type "application/json";

    # enable xss, and use "callback"
    xss_get on;
    xss_callback_arg callback;

    # get data from memcached, proxy if not found
    set memcached_key $key;
    memcached_pass $uri;
    error_page 404 @proxy;
}