PHP_ cURL Change User Rank (ROBLOX)

<?php

if (!isset($_GET['userId']) || !isset($_GET['roleId'])) {
    exit('Error: No user and/or role specified.');
}
// I wonder what this could be.
$groupId = 1076;

// This is used later when GETing and POSTing to authenticate who we are to roblox
$roblosec = '[redacted for obvious reason]';
$csrf = '';

function get($url) {
    global $roblosec;

    $ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_COOKIE, '.ROBLOSECURITY=' . $roblosec);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_HEADER, 1);

    $result = curl_exec($ch);

    if (curl_errno($ch)) {
        exit('cURL error: ' . curl_error($ch));
    }

    curl_close($ch);

    return $result;
}

function post($url, $data) {
    global $roblosec, $csrf, $groupId;

    if (is_array($data)) {
        $temp_data = '';

        foreach($data as $k => $v) {
            $temp_data .= $k . '=' . $v . '&';
        }

        $data = substr($temp_data, 0, -1);
    }

    $ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLINFO_HEADER_OUT, true);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_COOKIE, '.ROBLOSECURITY=' . $roblosec);
    curl_setopt($ch, CURLOPT_HEADER, 1);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
    curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36');
    curl_setopt($ch, CURLOPT_HTTPHEADER, array('Accept-Encoding: gzip, deflate', 'Content-Length: 0', 'Origin: http://www.roblox.com', 'Content-Type: application/x-www-form-urlencoded; charset=UTF-8', 'X-CSRF-TOKEN: ' . $csrf, 'X-Requested-With: XMLHttpRequest'));

    $result = curl_exec($ch);

    if (curl_errno($ch)) {
        exit('cURL error: ' . curl_error($ch));
    }

    curl_close($ch);

    return $result;
}

// Grap the csrf token
preg_match('/Roblox\.XsrfToken\.setToken\(\'([^\']+)\'\);/sm', get('http://www.roblox.com/My/GroupAdmin.aspx?gid=' . $groupId), $m);
$csrf = $m[1];

// And now we actually change the user's rank
echo nl2br(htmlentities(post('http://www.roblox.com/groups/api/change-member-rank?groupId=' . $groupId . '&newRoleSetId=' . $_GET['roleId'] . '&targetUserId=' . $_GET['userId'], '')));

?>