Summary of Smarty Caching Technology_PHP Tutorial

Everyone should know that reasonable use of cache can effectively reduce the server pressure of the website. As a very excellent PHP template engine, php Smarty provides us with very simple and diverse caching operations. Let’s Let's learn some tips on smarty cache operations. Here we will analyze how to enable and use smarty cache, how to clear smarty cache, and smarty's three caching mechanisms: global cache, partial cache, and local cache.

1. Enable and use smarty cache

To enable smarty's cache, just set caching to true in the smarty setting parameters and specify cache_dir. At the same time, set the cache_lefetime parameter to specify the cache lifetime (in seconds). If you want to generate multiple different caches for the same page, you can add the second parameter cache_id in display or fetch, such as:

$smarty->display('index.tpl',$my_cache_id);

This feature can be used to cache different $_GETs differently.

2. Clear smarty cache

There are generally several ways to clear smarty cache:

clear_all_cache();//清除所有缓存
clear_cache('index.tpl');//清除指定模板index.tpl的缓存
clear_cache('index.tpl',cache_id);//清除指定模板指定id的缓存

3. Global Cache

Global caching is to generate cache pages for all pages of the entire website. To set the global cache, first we need to operate the smarty configuration file, enable the cache, specify the cache file directory, and set the cache survival time. The setting parameters are as follows:

$smarty->cache_dir='./cache/'; //设置存放缓存文件的文件夹
$smarty->caching=1;//开启缓存 0、FALSE代表关闭|非0数字、TRUE代表开启
$smarty->cache_lifetime=3600//单位为秒(如果填写-1为永不过期)

Next we need to go to the specific php page to set the name of the specific cache file corresponding to it. In the php page, it can be written as follows:

$smarty->display('list2.html',md5($_SERVER['REQUEST_URI']));//将当前页面的URL(包含?后面的所有参数)进行md5加密然后设置缓存文件名

It should be noted that:

$smarty->display('corresponding template file name', 'supplementary part of cache file name') this method.

The second parameter is not required. If not written, the cache file name is the encrypted file of the template file name. But this will encounter a more difficult problem, such as:

http://www.phpernote.com/article.php?id=5

http://www.phpernote.com/article.php?id=7

These two URLs correspond to different contents, but the generated cache file names are the result of article encryption. This will cause the user to query different content but access the same cache file. Therefore, it is recommended to add an auxiliary parameter. It is a more reliable method to encrypt the access URL (including all parameters after ?) md5.

4. Partial caching

Partial caching means specifying some files to generate cache files, not all files on the website. The essence of partial caching is actually partial non-caching, which means that it is not to specify which files should be cached, but to specify specific files not to be cached. Now assume there are 3 files:

http://www.phpernote.com/index.php //Requires caching

http://www.phpernote.com/cate.php //Requires caching

http://www.phpernote.com/article.php //No caching required

You still need to write $smarty->display('corresponding template file name', 'supplementary part of cache file name') in the php files of the first two files.

But in the third file, we need to specifically indicate that no cache is required. The specific method is to write the following code before displaying the specified template:

$smarty->clear_cache('corresponding template file name');//In fact, it can be written before or after $smarty->display('corresponding template file name')

Of course $smarty->display('corresponding template file name') still needs to be written. I don't want to generate a cache, so the second parameter is not needed.

Note: The parameters of $smarty->clear_cache() and $smarty->display() must be written consistently

5. Partial caching

Partial caching is to specify certain local places under the same page to generate cache. In fact, it does not specify which parts generate cache, but which parts do not generate cache (this is similar to the operation idea of ​​partial cache). Let’s first look at the following example:

Part of the article.php file is as follows:

<?php
$time=time();
$smarty->assign('time',$lanmuarr);
function insert_timeget(){
	return time();
}
$smarty->display('article.html');

The corresponding code of the template file article.html is as follows:

<body>
{$time}<!--开启缓存后，重复刷新这个值不会变-->
{insert name='timeget'}<!--开启缓存后，重复刷新这个值会变-->
</body>

Here is an explanation of the above example: In PHP, we only need to define a custom function named insert_ (note the underscore) with a custom supplementary name. The value returned in it does not require assign() Method passing can be called directly in the template page as {insert name='custom supplementary name'}. At the same time, it will not be affected by the cache and refreshed in real time.

Another addition is that if you feel that using smarty cache is not enough, you can also use custom cache. How to use custom cache?

Here you need to set cache_handler_func to use a custom function to handle the cache, such as:

$smarty->cache_handler_func="myCache";
function myCache($action,&$smarty_obj,&$cache_content,$tpl_file=null,$cache_id=null,$compile_id=null){
	switch($action){
		case "read"://读取缓存内容
		case "write"://写入缓存
		case "clear"://清空
	}
}

I won’t go into details here. Readers can refer to relevant documents. The author is not very clear about this and is afraid of sharing it and misleading others.

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