smarty/docs/programmers/caching/caching-cacheable.md

Controlling Cacheability of Output {#caching.cacheable}
==================================

If caching is enabled normally the whole final output of the page gets
cached. However Smarty3 offers several options how to exclude sections
of your output from caching.

> **Note**
>
> Be sure any variables used within a non-cached section are also
> assigned from PHP when the page is loaded from the cache.

Cacheability of Template Section {#cacheability.sections}
--------------------------------

A larger section of your template can easily excluded from caching by
using the [`{nocache}`](#language.function.nocache) and
[`{/nocache}`](#language.function.nocache) tags.



    Today's date is
    {nocache}
    {$smarty.now|date_format}
    {/nocache}

       

The above code will output the current date on a cached page.

Cacheability of Tags {#cacheability.tags}
--------------------

Caching for an individual tag can be disabled by adding the \"nocache\"
option flag to the tag.


    Today's date is
    {$smarty.now|date_format nocache}

        

Cacheability of Variables {#cacheability.variables}
-------------------------

You can [`assign()`](#api.assign) variables as not cachable. Any tag
which uses such variable will be automatically executed in nocache mode.

> **Note**
>
> If a tag is executed in nocache mode you must make sure that all other
> variables used by that tag are also assigned from PHP when the page is
> loaded from the cache.

> **Note**
>
> The nocache status of an assigned variable will effect the compiled
> template code. If you change the status you must manually delete
> existing compiled and cached template files to force a recompile.


    // assign $foo as nocahe variable
    $smarty->assign('foo',time(),true);


    Dynamic time value is {$foo}

        

Cacheability of Plugins {#cacheability.plugins}
-----------------------

The cacheability of plugins can be declared when registering them. The
third parameter to [`registerPlugin()`](#api.register.plugin) is called
`$cacheable` and defaults to TRUE.

When registering a plugin with `$cacheable=false` the plugin is called
everytime the page is displayed, even if the page comes from the cache.

> **Note**
>
> The `$cacheable` status will affect the compiled template code. If you
> change the status you must manually delete existing compiled and
> cached template files to force a recompile.

Example `index.php`:

    <?php
    $smarty->setCaching(Smarty::CACHING_LIFETIME_CURRENT);

    function smarty_block_dynamic($param, $content, $smarty) {
        return $content;
    }
    $smarty->registerPlugin('block','dynamic', 'smarty_block_dynamic', false);

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

       

where `index.tpl` is:


    Page created: {'0'|date_format:'%D %H:%M:%S'}

    {dynamic}

    Now is: {'0'|date_format:'%D %H:%M:%S'}

    ... do other stuff ...

    {/dynamic}

       

When reloading the page you will notice that both dates differ. One is
"dynamic" one is "static". You can do everything between
`{dynamic}...{/dynamic}` and be sure it will not be cached like the rest
of the page.

> **Note**
>
> The above example shall just demonstrate how a dynamic block plugins
> works. See
> [`Cacheability of Template Section`](#cacheability.sections) on how to
> disable caching of a template section by the built-in
> [`{nocache}`](#language.function.nocache) and
> [`{/nocache}`](#language.function.nocache) tags.