php实现远程网络文件下载到服务器指定目录

/**
 * @param $url 下载地址
 * @param string $publicDir 文件存放地址
 * @param string $filename  文件名称
 * @param int $type
 * @return array|bool
 */
public function getDownload($url, $publicDir = '', $fileName = '', $type = 0) {
    //获取文件路径
    $newOneDir = substr($publicDir,0,strrpos($publicDir,"/"));
    if (trim($url) == '') {
        return false;
    }
    //检验访问url是否有效
    $array = get_headers($url,1);
    if(!preg_match('/200/',$array[0])){
        return false;
    }
    if (trim($publicDir) == '') {
        return false;
    }
    //创建保存目录
    if (!file_exists($newOneDir) && !mkdir($newOneDir, 0777, true)) {
        return false;
    }
//原来文件存在则删除
        if (file_exists($save_dir)) {
            unlink($save_dir);
        }
    //获取远程文件所采用的方法
    if ($type) {
        $ch = curl_init();
        $timeout = 5;
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
        $content = curl_exec($ch);
        curl_close($ch);
    } else {
        ob_start();
        readfile($url);
        $content = ob_get_contents();
        ob_end_clean();
    }
    $size = strlen($content);
    //文件大小
    $fp2 = @fopen($publicDir, 'a');
    fwrite($fp2, $content);
    fclose($fp2);
    unset($content, $url);
    return array(
        'file_name' => $fileName,
        'save_path' => $publicDir,
        'file_size' => $size
    );
}