php stream proxy

stream.php

<?php 

class stream
{
    private static $ignore=['Host'];

    public static function init($url)
    {
        $headers = [];
        foreach(getallheaders() as $k => $v)
        {
            if(!in_array($k,self::$ignore,true))
            {
                $headers[]="{$k}:$v";
            }
        }
        $opts = 
        [
            'http'=>
            [
                'protocol_version'=>1.1,
                'method'=>$_SERVER['REQUEST_METHOD'],
                'header'=>implode("\r\n",$headers),
                'content'=>file_get_contents('php://input')
            ]
        ];
        $r=stream_context_create($opts);
        $remote = fopen($url, 'r',false,$r);
        $output = fopen('php://output','w');
        if($output&&$remote)
        {
            foreach($http_response_header as $h)
            {
                header($h);
            }
            return stream_copy_to_stream($remote,$output);
        }
    }
}

if(!empty($_GET['u']) && filter_var($_GET['u'],FILTER_VALIDATE_URL))
{
    stream::init($_GET['u']);
}