<?php    function curl_request($url, $data=null, $method='get', $header = array("content-type: application/json"), $https=true, $timeout = 5){       $method = strtoupper($method);       $ch = curl_init();//初始化       curl_setopt($ch, CURLOPT_URL, $url);//访问的URL       curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);//只获取页面内容，但不输出       if($https){           curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);//https请求 不验证证书           curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);//https请求 不验证HOST       }       if ($method != "GET") {           if($method == 'POST'){               curl_setopt($ch, CURLOPT_POST, true);//请求方式为post请求           }           if ($method == 'PUT' || strtoupper($method) == 'DELETE') {               curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $method); //设置请求方式           }           curl_setopt($ch, CURLOPT_POSTFIELDS, $data);//请求数据       }       curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);       curl_setopt($ch, CURLOPT_HTTPHEADER, $header); //模拟的header头       //curl_setopt($ch, CURLOPT_HEADER, false);//设置不需要头信息       $result = curl_exec($ch);//执行请求       curl_close($ch);//关闭curl，释放资源       return $result;    }    $url=$_GET["url"];    $uu=parse_url($url);    $host=isset($uu["host"])?$uu["host"]:"";    $scheme=isset($uu["scheme"])?$uu["scheme"]:"";    if(empty($host)){        die("host is null");    }    if(empty($scheme)){        die("scheme is null");    }    //https://ctf.pediy.com/upload/team/762/team236762.png?    if($host=="ctf.pediy.com"||$host=="127.0.0.1"||$host=="localhost"){      //echo curl_request("http://123.57.254.42/flag.php","get",[],true,5);//get flag      echo curl_request($url,'',"get",[],true,5);    }else{      die("host not allow");    }    ?>