Thanks for sharing a good script! Here is solution if you do not have CURL on your web server (it is almost impossible but who knows?):
<?php
$proxy_url = 'http://freeproxylist.org/en/downloader.php?key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxx&filter=usca|any|23|2|any|any|0|10|15.0000|70|10'; // DYNAMIC LINK
$path = 'data/proxy_'.date("YmdHis").'.txt'; // PATH WHERE THE FILE WILL LIVE ... MUST BE WRITABLE
$buffer = file_get_contents($proxy_url);
file_put_contents($path, $buffer);
?>
If you need to have all proxy servers as array in your script then you can use this method:
<?php
$proxy_url = 'http://freeproxylist.org/en/downloader.php?key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxx&filter=usca|any|23|2|any|any|0|10|15.0000|70|10'; // DYNAMIC LINK
$proxy_servers = array_map('trim', file($proxy_url));
echo $proxy_servers[0];
echo $proxy_servers[1];
?>