例子15-5. 使用MySQL作为缓存源的例子
<?php
/**************************************************
示范用法：
include('Smarty.class.php');
include('mysql_cache_handler.php');
$smarty = new Smarty;
$smarty->cache_handler_func = 'mysql_cache_handler';
$smarty->display('index.tpl');
MySQL数据库的格式为：
create database SMARTY_CACHE;
create table CACHE_PAGES(
CacheID char(32) PRIMARY KEY,
CacheContents MEDIUMTEXT NOT NULL
);
**************************************************/
function mysql_cache_handler($action, &$smarty_obj, &$cache_content, $tpl_file=null, $cache_id=null, $compile_id=null, $exp_time=null)
{
// 设置数据库主机、用户和密码
$db_host = 'localhost';
$db_user = 'myuser';
$db_pass = 'mypass';
$db_name = 'SMARTY_CACHE';
$use_gzip = false;
// 设置唯一的cache id
$CacheID = md5($tpl_file.$cache_id.$compile_id);
if(! $link = mysql_pconnect($db_host, $db_user, $db_pass)) {
$smarty_obj->_trigger_error_msg('cache_handler: could not connect to database');
return false;
}
mysql_select_db($db_name);
switch ($action) {
case 'read':
// 从数据库中读入缓存
$results = mysql_query("select CacheContents from CACHE_PAGES where CacheID='$CacheID'");
if(!$results) {
$smarty_obj->_trigger_error_msg('cache_handler: query failed.');
}
$row = mysql_fetch_array($results,MYSQL_ASSOC);
if($use_gzip && function_exists('gzuncompress')) {
$cache_content = gzuncompress($row['CacheContents']);
} else {
$cache_content = $row['CacheContents'];
}
$return = $results;
break;
case 'write':
// 将缓存保存至数据库
if($use_gzip && function_exists("gzcompress")) {
// compress the contents for storage efficiency
$contents = gzcompress($cache_content);
} else {
$contents = $cache_content;
}
$results = mysql_query("replace into CACHE_PAGES values(
'$CacheID',
'".addslashes($contents)."')
");
if(!$results) {
$smarty_obj->_trigger_error_msg('cache_handler: query failed.');
}
$return = $results;
break;
case 'clear':
// 清除缓存
if(empty($cache_id) && empty($compile_id) && empty($tpl_file)) {
// 全部清除
$results = mysql_query('delete from CACHE_PAGES');
} else {
$results = mysql_query("delete from CACHE_PAGES where CacheID='$CacheID'");
}
if(!$results) {
$smarty_obj->_trigger_error_msg('cache_handler: query failed.');
}
$return = $results;
break;
default:
// 错误，未知的动作
$smarty_obj->_trigger_error_msg("cache_handler: unknown action \"$action\"");
$return = false;
break;
}
mysql_close($link);
return $return;
}
?>
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