<?php
error_reporting(0);
$main = new Main();
$main->libs();

Class Main{
    private $libDir = __DIR__.'/'; // 静态资源保存目录
    private $host = 'https://cdn.bootcdn.net'; // 镜像站点

    public function libs(){
        $url = $_SERVER['REQUEST_URI'];
        $this->header($url);
        $url_array = explode('?',$url); $url = $url_array['0']; // 处理文件版本号  适应自己上传的静态资源
        if(is_file($this->libDir.$url)){
            if(count(explode('.php',$url)) > 1){
                http_response_code(403); // 屏蔽下载php文件
            }else{
                echo file_get_contents($this->libDir.$url);
            }
        }else{
            $new_url = $this->host.$url;
            $data = $this->request($new_url);
            if($data['headers']['http_code'] == 200 && strlen($data['output']) > 10){
                $this->writeFile($url, $data['output']);
                echo $data['output'];
            }else{
                header('HTTP/1.1 404 Not Found');
            }
        }
    }

    // 写入文件  去掉首尾 得到需要创建的目录 依次检查并创建 再写入
    private function writeFile($url, $data){
        $url_array = explode('/', $url);
        array_shift($url_array);  $file_name = array_pop($url_array); $new_v = '';
        $file_name_array = explode('?',$file_name); $file_name = $file_name_array['0']; // 处理文件版本号
        foreach ($url_array as $k => $v) {
            $new_v = $new_v.'/'.$v;
            if(!is_dir($this->libDir.$new_v)){ mkdir($this->libDir.$new_v); }
        }
        return file_put_contents($this->libDir.$new_v.'/'.$file_name,$data);
    }

    private function header($url){
        ob_end_clean();
        $url = explode('?',$url); // 处理文件版本号
        $url_array = explode('.', $url[0]);
        $name = $url_array[count($url_array)-1];
        switch ($name) {
            case 'css':
                header('Content-type: text/css');
                break;
            case 'js':
                header('Content-type: text/javascript');
                break;
            case 'png':
                header('Content-Type: image/jpeg');
                break;
            case 'gif':
                header('Content-Type: image/jpeg');
                break;
            
            default:
                header('Content-Type: application/octet-stream');
                break;
        }
    }

    // 发起请求
    private function request($Url){
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $Url);
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST,'GET');
        curl_setopt($ch, CURLOPT_POST, false);
        curl_setopt($ch, CURLOPT_TIMEOUT, 10);
        //curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        //curl_setopt($ch, CURLOPT_ENCODING, 'gzip');
        $output = curl_exec($ch);
        $headers = curl_getinfo($ch);
        curl_close($ch);
        return ['headers' => $headers, 'output' => $output];
    }
}