Resources资源

Resource plugins are meant as a generic way of providing template sources or PHP script components to Smarty. Some examples of resources: databases, LDAP, shared memory, sockets, and so on.
资源插件被认为是为Smarty提供模板源或PHP脚本组件的一种普通方式。一些资源例子如:数据库、LDAP、共享内存、sockets（套接字）等等。

There are a total of 4 functions that need to be registered for each type of resource. Every function will receive the requested resource as the first parameter and the Smarty object as the last parameter. The rest of parameters depend on the function.
需要为每一种类型的资源注册四个函数。每一个函数将接收被请求的资源作为第一个参数，Smarty对象作为最后一个参数。剩余的参数取决于函数的不同。

The first function is supposed to retrieve the resource. Its second parameter is a variable passed by reference where the result should be stored. The function is supposed to return true if it was able to successfully retrieve the resource and false otherwise.
第一个函数将会检索资源。它的第二个参数是一个参考引用变量，结果值会存放到该变量里面。如果此函数能成功的检索到资源，将会返回true，否则返回false。

The second function is supposed to retrieve the last modification time of the requested resource (as a UNIX timestamp). The second parameter is a variable passed by reference where the timestamp should be stored. The function is supposed to return true if the timestamp could be succesfully determined, and false otherwise.
第二个函数将会检索被请求资源的最后修改时间（UNIX时间戳）。它的第二个参数是一个参考引用变量，时间戳值会存放到该变量里面。如果此函数能成功的确定时间戳，将会返回true，否则返回false。

The third function is supposed to return true or false, depending on whether the requested resource is secure or not. This function is used only for template resources but should still be defined.
第三个函数将会返回true或false，取决于被请求资源是否安全。这个函数仅用于模板资源，但仍应被定义。

The fourth function is supposed to return true or false, depending on whether the requested resource is trusted or not. This function is used for only for PHP script components requested by {include_php} tag or {insert} tag with src attribute. However, it should still be defined even for template resources.
第四个函数将会返回true或false，取决于被请求资源是否被信任。这个函数仅用于被{include_php}或 {insert}标记以 src 属性请求的PHP脚本组件。但仍应被定义，甚至用于模板资源也不例外。

See also register_resource(), unregister_resource().

<?php
/*
 * Smarty plugin
 * ------------------------------------------------------------- 
 * File:     resource.db.php
 * Type:     resource
 * Name:     db
 * Purpose:  Fetches templates from a database
 * -------------------------------------------------------------
 */
function smarty_resource_db_source($tpl_name, &$tpl_source, &$smarty)
{
    // do database call here to fetch your template,
    // populating $tpl_source
    $sql = new SQL;
    $sql->query("select tpl_source
                   from my_table
                  where tpl_name='$tpl_name'");
    if ($sql->num_rows) {
        $tpl_source = $sql->record['tpl_source'];
        return true;
    } else {
        return false;
    }
}

function smarty_resource_db_timestamp($tpl_name, &$tpl_timestamp, &$smarty)
{
    // do database call here to populate $tpl_timestamp.
    $sql = new SQL;
    $sql->query("select tpl_timestamp
                   from my_table
                  where tpl_name='$tpl_name'");
    if ($sql->num_rows) {
        $tpl_timestamp = $sql->record['tpl_timestamp'];
        return true;
    } else {
        return false;
    }
}

function smarty_resource_db_secure($tpl_name, &$smarty)
{
    // assume all templates are secure
    return true;
}

function smarty_resource_db_trusted($tpl_name, &$smarty)
{
    // not used for templates
}
?>