<?php
header('Content-Type: application/json');

$df = disk_free_space("/");
$dt = disk_total_space("/");
$used = $dt - $df;

$percent = round(($used / $dt) * 100, 2);

echo json_encode([
    "total" => $dt,
    "free" => $df,
    "used" => $used,
    "percent" => $percent
]);
?>