header("Content-Type", "text/csv", true);
header("Content-Disposition", "attachment; filename='my-filename.csv'", true);
$fp = fopen("php://stdout", "w");


Then do your normal fputcsv() stuff. Don’t forget to send the headers prior to opening that pointer. Much simpler than writing to a temp file and reading it back later if all you’re doing is sending it to the user ;)