ecshop页面缓存详解

ecshop缓存详解

小结：主要根据$cache_id,caching参数判断是否需要缓存，若缓存文件存在且未过期则直接从缓存文件中读取缓存，若缓存文件过期则重新编译，判断编译文件是否过期，若未过期则直接生成缓存，若过期了则重新编译。

• is_cached方法解析
• display页面呈现方法
• catch页面编译方法

---

代码块

判断缓存是否存在：

#判断是否存在该页面的缓存
if (!$smarty->is_cached('index.dwt', $cache_id))
{
    #do something ...
}
$smarty->display('index.dwt', $cache_id);

---------------------------------------------------------

#判断缓存函数
function is_cached($filename, $cache_id = '')
    {
        $cachename = basename($filename, strrchr($filename, '.')) . '_' . $cache_id;
        if ($this->caching == true && $this->direct_output == false)
        {
            $hash_dir = $this->cache_dir . '/' . substr(md5($cachename), 0, 1);
            #判断缓存文件是否存在
            if ($data = @file_get_contents($hash_dir . '/' . $cachename . '.php'))
            {
                $data = substr($data, 13);
                $pos  = strpos($data, '<');
                $paradata = substr($data, 0, $pos);
                $para     = @unserialize($paradata);
                #判断缓存是否过期
                if ($para === false || $this->_nowtime > $para['expires'])
                {
                    $this->caching = false;

                    return false;
                }
                $this->_expires = $para['expires'];
                #未过期则将缓存文件读入的字符串赋值给template_out
                $this->template_out = substr($data, $pos);
                #判断每一个模板是否过期
                foreach ($para['template'] AS $val)
                {
                    $stat = @stat($val);
                    if ($para['maketime'] < $stat['mtime'])
                    {
                        $this->caching = false;

                        return false;
                    }
                }
            }
            else
            {
                $this->caching = false;

                return false;
            }

            return true;
        }
        else
        {
            return false;
        }
    }
--------------------------------------------------------- 
#根据上面的is_cached判断是否从缓存中读取
function display($filename, $cache_id = '')
    {
        $this->_seterror++;
        error_reporting(E_ALL ^ E_NOTICE);

        $this->_checkfile = false;
        #此处处理文件的呈现
        $out = $this->fetch($filename, $cache_id);

        if (strpos($out, $this->_echash) !== false)
        {
            $k = explode($this->_echash, $out);
            foreach ($k AS $key => $val)
            {
                if (($key % 2) == 1)
                {
                    $k[$key] = $this->insert_mod($val);
                }
            }
            $out = implode('', $k);
        }
        error_reporting($this->_errorlevel);
        $this->_seterror--;

        echo $out;
    }
---------------------------------------------------------
 /**
     * 处理模板文件
     *
     * @access  public
     * @param   string      $filename
     * @param   sting      $cache_id
     *
     * @return  sring
     */
    function fetch($filename, $cache_id = '')
    {
        if (!$this->_seterror)
        {
            error_reporting(E_ALL ^ E_NOTICE);
        }
        $this->_seterror++;

        if (strncmp($filename,'str:', 4) == 0)
        {
            $out = $this->_eval($this->fetch_str(substr($filename, 4)));
        }
        else
        {
            if ($this->_checkfile)
            {
                if (!file_exists($filename))
                {
                    $filename = $this->template_dir . '/' . $filename;
                }
            }
            else
            {
                $filename = $this->template_dir . '/' . $filename;
            }

            if ($this->direct_output)
            {
                $this->_current_file = $filename;
                #如果direct_output为真，就直接输出不用缓存
                $out = $this->_eval($this->fetch_str(file_get_contents($filename)));
            }
            else
            {
                #有缓存id和caching为真，则直接读取缓存到$out中
                if ($cache_id && $this->caching)
                {
                    $out = $this->template_out;

                }
                else
                {
                    if (!in_array($filename, $this->template))
                    {
                        $this->template[] = $filename;
                    }
                    #如果缓存文件不存在则编译源文件
                    $out = $this->make_compiled($filename);

                    if ($cache_id)
                    {
                        #如果存在cache_id存在则生成一份缓存保存
                        $cachename = basename($filename, strrchr($filename, '.')) . '_' . $cache_id;
                        $data = serialize(array('template' => $this->template, 'expires' => $this->_nowtime + $this->cache_lifetime, 'maketime' => $this->_nowtime));
                        $out = str_replace("\r", '', $out);

                        while (strpos($out, "\n\n") !== false)
                        {
                            $out = str_replace("\n\n", "\n", $out);
                        }

                        $hash_dir = $this->cache_dir . '/' . substr(md5($cachename), 0, 1);
                        if (!is_dir($hash_dir))
                        {
                            mkdir($hash_dir);
                        }
                        if (file_put_contents($hash_dir . '/' . $cachename . '.php', '<?php exit;?>' . $data . $out, LOCK_EX) === false)
                        {
                            trigger_error('can\'t write:' . $hash_dir . '/' . $cachename . '.php');
                        }
                        $this->template = array();
                    }
                }
            }
        }

        $this->_seterror--;
        if (!$this->_seterror)
        {
            error_reporting($this->_errorlevel);
        }

        return $out; // 返回html数据
    }

来源：CSDN

作者：徐乐乐1

链接：https://blog.csdn.net/b1303110335/article/details/51565325