add_header 'Access-Control-Allow-Origin' '*' always;
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
#
# Custom headers and headers various browsers *should* be OK with but aren't
#
add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type' always;
#
# Tell client that this pre-flight info is valid for 20 days
#
add_header 'Access-Control-Max-Age' $access_control_max_age always;

if ($request_method = OPTIONS) {
  return 204;
}