if ($request_method = OPTIONS ) {
      add_header 'Access-Control-Allow-Origin'  '*';
      add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS, HEAD, PUT';
      add_header 'Access-Control-Allow-Headers' 'Authorization, Origin, X-Requested-With, Content-Type, Accept';
      return 200;
    }
    add_header 'Access-Control-Allow-Origin' '*';
    add_header 'Access-Control-Allow-Methods' '*';
    add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
    add_header 'Access-Control-Expose-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';
    add_header Access-Control-Allow-Credentials 'true';