<?php
ob_start();
$login = "xxx";
$haslo = "xx";

$id = "884343604";
$url = 'http://api.filesonic.com/link?method=getDownloadLink&u='.$login.'&p='.$haslo.'&ids='.$id.'&format=json';
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$str = curl_exec($ch);
curl_close($ch);
echo $url;
die;
$str = json_decode($str, TRUE);

$download =  trim($str['FSApi_Link']['getDownloadLink']['response']['links']['0']['url']);
$nazwa =  trim($str['FSApi_Link']['getDownloadLink']['response']['links']['0']['filename']);

header('Content-Disposition: attachment; filename='.$nazwa);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $download);
curl_setopt($ch, CURLOPT_BINARYTRANSFER,1);
curl_exec($ch);
curl_close($ch);

ob_end_flush();
?>