if ($request_method = 'POST') {
    add_header 'Access-Control-Allow-Origin' '*' always;
    add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
    add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range' always;
    add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
}
if ($request_method = 'GET') {
    add_header 'Access-Control-Allow-Origin' '*' always;
    add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
    add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range' always;
    add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
}