Quick and easy flood protection?

Question

I have a site where a user submits a message using AJAX to a file called like.php. In this file the users message is submitted to a database and it then sends a

Answer 1

You don't need to go through the whole record file. Instead:

 FLOODPOOL_DURATION && substr($entry, 0, 3) === 'fp_'){
            unlink($filename);
        }
    }
    closedir($handle);
}

Usage example:

if(floodpool_check($_SERVER['REMOTE_ADDR'])){
    header("HTTP/1.1 429 Too Many Requests");
    exit("Hit some *");
}