PHP get remote file, anti anti spam

get.php

<?php
$url = getParam('url');
$encode = getParam('encode');

$file = 'cache/'.md5($url);
$exist = file_exists($file);
if($exist && (time() - filemtime($file) < 3600)){	// use cache during 10 minutes
	echo file_get_contents($file);
	exit();
}

@list($header, $content) = curlget($url);

if(strpos(trim($content), '<script>') === 0){
    $i = 0;
    do {
        list($header, $content) = curlget($url);
        $ret = preg_match('/\)\(\[\'[^)]+\)/', $content, $matchs);
        if(++$i == 3) break;
        if(!$ret) {
			sleep(1);
		}
    } while(!$ret);
    if($ret){
        $str = trim($matchs[0], '()[]\'');
        $arr = explode("', '", $str);

        preg_match('/b d=\[([^\]]+)/', $content, $matchs);
        $sort = explode(',', $matchs[1]);

        $str = '';
        foreach($sort as $i){
            $str .= $arr[$i];
        }

        if(strpos($str, '__jsl_clearance') !== 0){
            $arr2 = array();
            for($i = count($sort); $i--;){
                $arr2[$sort[$i]] = $arr[$i];
            }
            ksort($arr2);
            $str = implode($arr2);
        }

        $tmp = explode(';', $str);
        $cookie = trim($tmp[0]);	//get cookie from JS

        preg_match('/Set-Cookie:(.*);/iU', $header, $str);
        $cookie .= '; '.$str[1];	// append the old cookie
        list($header, $content) = curlget($url, $cookie);
    } else {
        $content = '';
    }
}
if(!empty($content)){
	if(!empty($encode) && !isImg($file)){
		$content = iconv($encode, 'UTF-8', $content);		// change given encode (GBK, GB2312) to utf8
	}
	file_put_contents($file, $content);
	echo $content;
	exit();
} else if($exist){
	echo file_get_contents($file);
	exit();
}

function curlget($url, $cookie = ''){
    $cookieFile = 'cache/cookie';
    if($cookie) {
        file_put_contents($cookieFile, $cookie);
    } else if (file_exists($cookieFile) && (time() - filemtime($cookieFile) < 3600)){
        $cookie = file_get_contents($cookieFile);
    }

    $ch = curl_init();
    $timeout = 5;
	$user_agent = 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/47.0.2526.111 Safari/537.36';

    $headers = array(
		'Accept-Encoding: gzip, deflate, sdch',
		'Accept-Language: zh-CN,zh;q=0.8',
		'Upgrade-Insecure-Requests: 1',
		'User-Agent: '.$user_agent,
		'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
		'Referer: '.$url,
		'Connection: keep-alive',
		'Cache-Control: max-age=0'
	);
    if($cookie) {
		$headers[] = 'Cookie: '.$cookie;
	}

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers); $HTTP_REQUEST_HEADER
    curl_setopt($ch, CURLOPT_ENCODING, '');
    curl_setopt($ch, CURLOPT_HEADER, 1);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
    curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);	// $_SERVER['HTTP_USER_AGENT']
    curl_setopt($ch, CURLOPT_COOKIESESSION, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
    curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);

    $content = curl_exec($ch);
    curl_close($ch);
    return explode("\r\n\r\n", $content, 2);
}
function getParam($key) {
    $val = $_GET[$key];
    return empty($val) ? $_POST[$key] : unescape($val);
}
function isImg($file) {
	$subfixs = array('.jpg', '.jpeg', '.png', '.gif');
    foreach($subfixs as $subfix){
		if (stripos($file, $subfix) !== false) {
			return true;
		}
	}
	return false;
}
?>