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.
Be sure any variables used within a non-cached section are also assigned from PHP when the page is loaded from the cache.
A larger section of your template can easily excluded from caching by using the {nocache}
and {/nocache} tags.
Example 15.10. Preventing a template section from being cached
Today's date is
{nocache}
{$smarty.now|date_format}
{/nocache}
The above code will output the current date on a cached page.
Caching for an individual tag can be disabled by adding the "nocache" option flag to the tag.
Example 15.11. Preventing tag output from being cached
Today's date is
{$smarty.now|date_format nocache}
You can assign() variables as not cachable.
Any tag which uses such variable will be automatically executed in nocache mode.
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.
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.
Example 15.12. Nocache Variables
// assign $foo as nocahe variable
$smarty->assign('foo',time(),true);
Dynamic time value is {$foo}
The cacheability of plugins can be
declared when registering them. The third parameter to
registerPlugin()
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. The plugin function behaves a little like an
{insert} function.
The $cacheable status 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.
In contrast to {insert}
the attributes to the plugins are not cached by default. They can be
declared to be cached with the fourth parameter
$cache_attrs. $cache_attrs
is an array of attribute-names that should be cached, so the
plugin-function get value as it was the time the page was written
to cache everytime it is fetched from the cache.
Example 15.13. Preventing a plugin's output from being cached
<?php
$smarty->setCaching(Smarty::CACHING_LIFETIME_CURRENT);
function remaining_seconds($params, $smarty) {
$remain = $params['endtime'] - time();
if($remain >= 0){
return $remain . ' second(s)';
}else{
return 'done';
}
}
$smarty->registerPlugin('function','remaining', 'remaining_seconds', false, array('endtime'));
if (!$smarty->isCached('index.tpl')) {
// fetch $obj from db and assign...
$smarty->assignByRef('obj', $obj);
}
$smarty->display('index.tpl');
?>
where index.tpl is:
Time Remaining: {remaining endtime=$obj->endtime}
The number of seconds till the endtime of $obj is reached
changes on each display of the page, even if the page is cached. Since the
endtime attribute is cached the object only has to be pulled from the
database when page is written to the cache but not on subsequent requests
of the page.
Example 15.14. Preventing a whole passage of a template from being cached
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.
The above example shall just demonstrate how a dynamic block plugins works.
See Cacheability of Template Section on how to disable
caching of a template section by the built-in {nocache}
and {/nocache} tags.