asiahighlights.com/application/core/MY_Output.php

<?php

//加载第三方用于解析html的类
require '/lib/simple_html_dom.php';

if (!defined('BASEPATH'))
    exit('No direct script access allowed');

class MY_Output extends CI_Output {
    // --------------------------------------------------------------------

    /**
     * Write a Cache File
     *
     * @access	public
     * @param 	string
     * @return	void
     */
    function _write_cache($output) {
        $cache_path = 'd:/Dropbox/wwwcache/asiahighlights.com';

        if (!is_dir($cache_path) OR ! is_really_writable($cache_path)) {
            log_message('error', "Unable to write cache file: " . $cache_path);
            return;
        }

        ///////改成按照URL保存缓存
        //优先使用提交过来的static_html_url做文件名，这是主动生成静态文件用的参数
        if (empty($_GET['static_html_url'])) {
            return FALSE;
        }
        $cache_path = $cache_path . $_GET['static_html_url'];
        if (mb_substr($cache_path, -1, 1) == '/') {
            $cache_path.='index.htm';
        }

        $this->create_folder_by_path(dirname($cache_path));

        //如果文件存在，先判断是否为缓存文件，防止覆盖原始程序文件
        if (@file_exists($cache_path)) {
            if (!$fp_read = @fopen($cache_path, FOPEN_READ)) {
                return FALSE;
            }

            flock($fp_read, LOCK_SH);

            $cache = '';
            if (filesize($cache_path) > 0) {
                $cache = fread($fp_read, filesize($cache_path));
            }

            flock($fp_read, LOCK_UN);
            fclose($fp_read);
            if (strpos($cache, '<!-- Generated by ') === false) {
                log_message('error', "is not cache file." . $cache_path);
                return FALSE;
            }
        }

        ///////

        if (!$fp = @fopen($cache_path, FOPEN_WRITE_CREATE_DESTRUCTIVE)) {
            log_message('error', "Unable to write cache file: " . $cache_path);
            return;
        }

        //解析html，生成不同版本的静态文件

        $html_object = str_get_html($output);
        if (!empty($html_object)) {

            //替换图片地址，用CDN分发
            foreach ($html_object->find('img') as $image) {
                if (strpos($image->src, '/pic/') !== false) {
                    $image->src = 'https://data.asiahighlights.com' . $image->src;
                } else if (strpos($image->src, '/image/') !== false) {
                    $image->src = 'https://data.asiahighlights.com' . $image->src;
                }
            }
            //保存PC端代码
            $output = $html_object->save();

            //生成移动版本
            foreach ($html_object->find('.hidden-xs') as $hidden_item) {
                $hidden_item->outertext = '';
            }
            $html_object->save($cache_path . '.mobile.htm');
        }

        ////// 


        if (flock($fp, LOCK_EX)) {
            fwrite($fp, $output . '<!-- Generated by ' . $_SERVER['HTTP_HOST'] . ' (' . date('c') . ') -->');
            flock($fp, LOCK_UN);
        } else {
            log_message('error', "Unable to secure a file lock for file at: " . $cache_path);
            return;
        }
        fclose($fp);
        @chmod($cache_path, FILE_WRITE_MODE);

        log_message('debug', "Cache file written: " . $cache_path);
    }

    // --------------------------------------------------------------------

    /*
     * 递归创建文件夹
     */
    function create_folder_by_path($dir, $mode = 0777) {
        if (!is_dir($dir)) {
            return @mkdir($dir, $mode, true);
        }
        return;
    }

}