Multiple Caches Per Page 每页多个缓存

Example 14-6. passing a cache_id to display()
例14-6.传给display()一个cache_id

require('Smarty.class.php');
$smarty = new Smarty;
$smarty->caching = true;
$my_cache_id = $_GET['article_id'];
$smarty->display('index.tpl',$my_cache_id);

Above, we are passing the variable $my_cache_id to display() as the cache_id. For each unique value of $my_cache_id, a separate cache will be generated for index.tpl. In this example, "article_id" was passed in the URL and is used as the cache_id.
上面，我们通过变量$my_cache_id作为cache_id来display()。在index.tpl里$my_cache_id的每个唯一值，会建立单独的缓存。在这个例子里，"article_id"在URL传送，并用作cache_id。

Technical Note: Be very cautious when passing values from a client (web browser) into Smarty (or any PHP application.) Although the above example of using the article_id from the URL looks handy, it could have bad consequences. The cache_id is used to create a directory on the file system, so if the user decided to pass an extremely large value for article_id, or write a script that sends random article_ids at a rapid pace, this could possibly cause problems at the server level. Be sure to sanitize any data passed in before using it. In this instance, maybe you know the article_id has a length of 10 characters and is made up of alpha-numerics only, and must be a valid article_id in the database. Check for this!
技术提示：要注意从客户端(web浏览器)传值到Smarty(或任何PHP应用程序)的过程。尽管上面的例子用article_id从URL传值看起来很方便，却可能有糟糕的后果[安全问题]。cache_id被用来在文件系统里创建目录，如果用户想为article_id赋一个很大的值，或写一些代码来快速发送随机的article_ids，就有可能会使服务器出现问题。确定在使用它之前清空已存在的数据。在这个例子，可能你知道article_id的长度(值吧？！)是10字符，并只由字符-数字组成，在数据库里是个可用的article_id。Check for this!要注意检查这个问题！〔要注意这个提示!不用再说了吧？〕

Be sure to pass the same cache_id as the second parameter to is_cached() and clear_cache().
确定传给is_cached()和clear_cache()的第二参数是同一个cache_id。

require('Smarty.class.php');
$smarty = new Smarty;
$smarty->caching = true;
$my_cache_id = $_GET['article_id'];
if(!$smarty->is_cached('index.tpl',$my_cache_id)) {
	// No cache available, do variable assignments here.
	$contents = get_database_contents();
	$smarty->assign($contents);
}
$smarty->display('index.tpl',$my_cache_id);

require('Smarty.class.php');
$smarty = new Smarty;
$smarty->caching = true;
// clear all caches with "sports" as the cache_id
$smarty->clear_cache(null,"sports");
$smarty->display('index.tpl',"sports");