自己做了个差量更新下来，但无法正常使用

问题描述

就是为了给KK的云签服务的，服务端是直接检测文件MD5值，然后程序端这边检测，下载。

现在问题来了，可以正常检测到文件差异，但更新不下来或者说是（无法下载文件）可是是利用其他思路的可以正常下载文件，说明服务器本身没有问题，请各位大神帮我看下程序上有没有什么问题。

程序代码

服务端

<?php
define('UPDATA_SOURCE', './Tieba'); //这个目录就是用来检查差异文件的
chdir(UPDATA_SOURCE);
if($_GET['action'] == 'filelist') {
    $dirs = array('./');
    $rt = array();
    do {
        $dir = array_pop($dirs);
        $tmp = scandir($dir);

        foreach($tmp as $f) {
            if($f == '.' || $f == '..')
                continue;

            $path = $dir . $f;

            if(is_dir($path)) {
                array_push($dirs, $path . '/');
            } elseif (is_file($path)) {
                $rt [] = $path;
            }
        }
    } while($dirs);

    foreach($rt as $file){
        $str[$file] = md5_file($file);
    }

    echo json_encode($str);
    exit();
} elseif($_GET['action'] == 'getfile') {
    if (!file_exists($_GET['path'])){
        header("Content-type: text/html; charset=utf-8");
        echo "File not found!";
        exit; 
    } else {
        $file = fopen($_GET['path'], "r"); 
        header("Content-type: application/octet-stream");
        header("Accept-Ranges: bytes");
        header("Accept-Length: " . filesize($_GET['path']));
        header("Content-Disposition: attachment; filename=" . array_pop(explode('/', $_GET['path'])));
        echo fread($file, filesize($_GET['path']));
        fclose($file);
        exit;
    }
}
?>

程序端

<?php
if(!defined('IN_KKFRAME')) exit('Access Denied');
class Updater{
    const UPDATE_URL = 'http://update.liujiantao.me/';
    public static function init(){
        global $_config;
        if($_config['version']){
            $current_version = $_config['version'];
        } else {
            $current_version = getSetting('version');
        }
        if ($current_version == VERSION) return;
        $version = $current_version;
        while($version){
            $filepath = SYSTEM_ROOT."./function/updater/{$version}.php";
            if(file_exists($filepath)){
                include $filepath;
                exit();
            } else{
                $version = substr($version, 0, strrpos($version, '.'));
            }
        }
        include SYSTEM_ROOT.'./function/updater/fallback.php';
        exit();
    }
    public static function check(){
        $data = kk_fetch_url(self::UPDATE_URL."updata.php?action=filelist");
        saveSetting('new_version', 0);
        if (!$data) return -1;
        $file_list = json_decode($data);
        if (!$file_list) return -2;
        $err_file = $list = array();
        foreach($file_list as $path => $hash) {
            $file_hash = md5_file(ROOT."./{$path}");
            if ($file_hash != $hash){
                $err_file[] = array($path, $hash);
                $list[] = $path;
            }
        }
        if(!$list) return 0;
        saveSetting('new_version', 1);
        sort($list);
        sort($err_file);
        CACHE::save('kk_updater', $err_file);
        CACHE::save('need_download', $err_file);
        DB::query('DELETE FROM download');
        return $list;
    }
    public static function loop(){
        if(defined('IN_XAE')) return array('status' => -3);
        $file_list = CACHE::get('need_download');
        list($path, $hash) = array_pop($file_list);
        if(!$path) return array('status' => 1);
        $ret = self::_download_file($path, $hash);
        if ($ret<0) return array('status' => $ret, 'file' => $path);
        CACHE::save('need_download', $file_list);
        $max = sizeof(CACHE::get('kk_updater'));
        $current = $max - sizeof($file_list);
        return array('status' => 0, 'precent' => round($current / $max * 100), 'file' => $path);
    }
    public static function write_file(){
        $err_file = $files = array();
        $query = DB::query('SELECT * FROM download ORDER BY path ASC');
        while($file = DB::fetch($query)){
            list($part, $path) = explode('|', $file['path'], 2);
            if(!$files[ $path ]){
                $file['content'] = pack('H*', $file['content']);
                $files[ $path ] = $file;
            } else {
                $files[ $path ]['content'] .= pack('H*', $file['content']);
            }
        }
        if(!$files) return array('status' => -255);
        foreach($files as $path => $file) {
            if(!self::_is_writable(ROOT.$path)) $err_file[] = $path;
        }
        if($err_file) array('status' => -1, 'files' => $err_file);
        foreach($files as $path => $file) {
            self::_write(ROOT.$path, $file['content']);
            if(md5_file(ROOT.$path) != md5($file['content'])) return array('status' => -2, 'file' => $path);
        }
        DB::query('DELETE FROM download');
        saveSetting('new_version', 0);
        return array('status' => 0);
    }
    private static function _write($path, $content){
        $fp = @fopen($path, 'wb');
        if(!$fp) return false;
        fwrite($fp, $content);
        fclose($fp);
        return true;
    }
    private static function _is_writable($path){
        if(!file_exists($path)){
            if(!file_exists(dirname($path))) @mkdir(dirname($path), 0777, true);
            @touch($path);
            @chmod($path, 0777);
        }else{
            if(!is_writable($path)) @chmod($path, 0777);
        }
        return is_writable($path);
    }
    private static function _download_file($path, $hash, $try = 1) {
        $content = kk_fetch_url(self::UPDATE_URL."updata.php?action=getfile&path={$path}");
        if (!$content) {
            if ($try == 3) {
                return -1;
            } else {
                return self::_download_file($path, $hash, $try + 1);
            }
        }
        if (md5($content) != $hash) {
            if ($try == 3) {
                return -2;
            } else {
                return self::_download_file($path, $hash, $try + 1);
            }
        }
        $length = $part = 0;
        while($length < strlen($content)){
            $part++;
            $part_length = strlen($content) - $length > 8192 ? 8192 : strlen($content) - $length;
            $_countent = substr($content, $length, $part_length);
            $length += $part_length;
            $_part = str_pad($part, 4, "0", STR_PAD_LEFT);
            DB::insert('download', array('path' => "{$_part}|".$path, 'content' => bin2hex($_countent)));
        }
        return 0;
    }
    private static function _getPluginList(){
        $pluginList = array();
        $list_dir = dir(ROOT.'./plugins/');
        while($dirName = $list_dir->read()){
            if($dirName == '.' || $dirName == '..' || !is_dir(ROOT."./plugins/{$dirName}")) continue;
            $pluginList[] = $dirName;
        }
        return $pluginList;
    }
}
?>