Advanced FeaturesObjects
Smarty allows access to PHP objects through the templates. There are
two ways to access them. One way is to register objects to the template,
then use access them via syntax similar to custom functions. The other way
is to assign objects to the templates and access them much like any other
assigned variable. The first method has a much nicer template syntax. It
is also more secure, as a registered object can be restricted to certain
methods or properties. However, a registered object cannot be looped over
or assigned in arrays of objects, etc. The method you choose will be
determined by your needs, but use the first method whenever possible to
keep template syntax to a minimum.
If security is enabled, no private methods or functions can be accessed
(begininning with "_"). If a method and property of the same name exist,
the method will be used.
You can restrict the methods and properties that can be accessed by
listing them in an array as the third registration parameter.
By default, parameters passed to objects through the templates are passed
the same way custom functions get them. An associative array is passed
as the first parameter, and the smarty object as the second. If you want
the parameters passed one at a time for each argument like traditional
object parameter passing, set the fourth registration parameter to false.
The optional fifth parameter has only effect with
format being true
and contains a list ob methods that should be treated as
blocks. That means these methods have a closing tag in the
template
({foobar->meth2}...{/foobar->meth2}) and
the parameters to the methods have the same synopsis as the
parameters for block-function-plugins: They get 4 parameters
$params,
$content,
&$smarty and
&$repeat and they also behave like
block-function-plugins.
using a registered or assigned object
register_object("foobar",$myobj);
// if we want to restrict access to certain methods or properties, list them
$smarty->register_object("foobar",$myobj,array('meth1','meth2','prop1'));
// if you want to use the traditional object parameter format, pass a boolean of false
$smarty->register_object("foobar",$myobj,null,false);
// We can also assign objects. Assign by ref when possible.
$smarty->assign_by_ref("myobj", $myobj);
$smarty->display("index.tpl");
?>
TEMPLATE:
{* access our registered object *}
{foobar->meth1 p1="foo" p2=$bar}
{* you can also assign the output *}
{foobar->meth1 p1="foo" p2=$bar assign="output"}
the output was {$output}
{* access our assigned object *}
{$myobj->meth1("foo",$bar)}
]]>
Prefilters
Template prefilters are PHP functions that your templates are ran through
before they are compiled. This is good for preprocessing your templates
to remove unwanted comments, keeping an eye on what people are putting
in their templates, etc. Prefilters can be either
registered or loaded from
the plugins directory by using
load_filter() function or by
setting
$autoload_filters variable.
Smarty will pass the template source code as the first argument, and
expect the function to return the resulting template source code.
using a template prefilter
/U","",$tpl_source);
}
// register the prefilter
$smarty->register_prefilter("remove_dw_comments");
$smarty->display("index.tpl");
?>
{* Smarty template index.tpl *}
]]>
Postfilters
Template postfilters are PHP functions that your templates are ran through
after they are compiled. Postfilters can be either
registered or loaded
from the plugins directory by using
load_filter() function or by
setting
$autoload_filters
variable. Smarty will pass the compiled template code as the first
argument, and expect the function to return the result of the
processing.
using a template postfilter
;\n\" ?>;\n".$tpl_source;
}
// register the postfilter
$smarty->register_postfilter("add_header_comment");
$smarty->display("index.tpl");
?>
{* compiled Smarty template index.tpl *}
{* rest of template content... *}
]]>
Output Filters
When the template is invoked via display() or fetch(), its output can be
sent through one or more output filters. This differs from postfilters
because postfilters operate on compiled templates before they are saved to
the disk, and output filters operate on the template output when it is
executed.
Output filters can be either
registered or loaded
from the plugins directory by using
load_filter() function or by
setting
$autoload_filters
variable. Smarty will pass the template output as the first argument,
and expect the function to return the result of the processing.
using a template outputfilter
register_outputfilter("protect_email");
$smarty->display("index.tpl");
// now any occurrence of an email address in the template output will have
// a simple protection against spambots
?>
]]>
Cache Handler Function
As an alternative to using the default file-based caching mechanism, you
can specify a custom cache handling function that will be used to read,
write and clear cached files.
Create a function in your application that Smarty will use as a
cache handler. Set the name of it in the
$cache_handler_func
class variable. Smarty will now use this to handle cached data. The
first argument is the action, which will be one of 'read', 'write' and
'clear'. The second parameter is the Smarty object. The third parameter
is the cached content. Upon a write, Smarty passes the cached content
in these parameters. Upon a 'read', Smarty expects your function to
accept this parameter by reference and populate it with the cached
data. Upon a 'clear', pass a dummy variable here since it is not used.
The fourth parameter is the name of the template file (needed for
read/write), the fifth parameter is the cache_id (optional), and the
sixth is the compile_id (optional).
Note: The last parameter ($exp_time) was added in Smarty-2.6.0.
example using MySQL as a cache source
cache_handler_func = 'mysql_cache_handler';
$smarty->display('index.tpl');
mysql database is expected in this format:
create database SMARTY_CACHE;
create table CACHE_PAGES(
CacheID char(32) PRIMARY KEY,
CacheContents MEDIUMTEXT NOT NULL
);
*/
function mysql_cache_handler($action, &$smarty_obj, &$cache_content, $tpl_file=null, $cache_id=null, $compile_id=null, $exp_time=null)
{
// set db host, user and pass here
$db_host = 'localhost';
$db_user = 'myuser';
$db_pass = 'mypass';
$db_name = 'SMARTY_CACHE';
$use_gzip = false;
// create unique 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':
// save cache to database
$results = mysql_query("select CacheContents from CACHE_PAGES where CacheID='$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")) {
$cache_contents = gzuncompress($row["CacheContents"]);
} else {
$cache_contents = $row["CacheContents"];
}
$return = $results;
break;
case 'write':
// save cache to database
if($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 = $results;
break;
case 'clear':
// clear cache info
if(empty($cache_id) && empty($compile_id) && empty($tpl_file)) {
// clear them all
$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:
// error, unknown action
$smarty_obj->_trigger_error_msg("cache_handler: unknown action \"$action\"");
$return = false;
break;
}
mysql_close($link);
return $return;
}
?>
]]>
Resources
The templates may come from a variety of sources. When you display or fetch
a template, or when you include a template from within another template,
you supply a resource type, followed by the appropriate path and template
name. If a resource is not explicitly given the value of $default_resource_type is
assumed.
Templates from $template_dir
Templates from the $template_dir do not require a template
resource, although you can use the file: resource for consistancy.
Just supply the path to the template you want to use relative to
the $template_dir root directory.
using templates from $template_dir
display("index.tpl");
$smarty->display("admin/menu.tpl");
$smarty->display("file:admin/menu.tpl"); // same as one above
?>
{* from within Smarty template *}
{include file="index.tpl"}
{include file="file:index.tpl"} {* same as one above *}
]]>
Templates from any directory
Templates outside of the $template_dir require the file: template
resource type, followed by the absolute path and name of the
template.
using templates from any directory
display("file:/export/templates/index.tpl");
$smarty->display("file:/path/to/my/templates/menu.tpl");
?>
{* from within Smarty template *}
{include file="file:/usr/local/share/templates/navigation.tpl"}
]]>
Windows Filepaths
If you are using a Windows machine, filepaths usually include a
drive letter (C:) at the beginning of the pathname. Be sure to use
"file:" in the path to avoid namespace conflicts and get the
desired results.
using templates from windows file paths
display("file:C:/export/templates/index.tpl");
$smarty->display("file:F:/path/to/my/templates/menu.tpl");
?>
{* from within Smarty template *}
{include file="file:D:/usr/local/share/templates/navigation.tpl"}
]]>
Templates from other sources
You can retrieve templates using whatever possible source you can
access with PHP: databases, sockets, LDAP, and so on. You do this
by writing resource plugin functions and registering them with
Smarty.
See resource plugins
section for more information on the functions you are supposed
to provide.
Note that you cannot override the built-in
file resource, but you can provide a resource
that fetches templates from the file system in some other way by
registering under another resource name.
using custom resources
query("select tpl_source
from my_table
where tpl_name='$tpl_name'");
if ($sql->num_rows) {
$tpl_source = $sql->record['tpl_source'];
return true;
} else {
return false;
}
}
function db_get_timestamp($tpl_name, &$tpl_timestamp, &$smarty_obj)
{
// 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 = $sql->record['tpl_timestamp'];
return true;
} else {
return false;
}
}
function db_get_secure($tpl_name, &$smarty_obj)
{
// assume all templates are secure
return true;
}
function db_get_trusted($tpl_name, &$smarty_obj)
{
// not used for templates
}
// register the resource name "db"
$smarty->register_resource("db", array("db_get_template",
"db_get_timestamp",
"db_get_secure",
"db_get_trusted"));
// using resource from php script
$smarty->display("db:index.tpl");
?>
{* using resource from within Smarty template *}
{include file="db:/extras/navigation.tpl"}
]]>
Default template handler function
You can specify a function that is used to retrieve template
contents in the event the template cannot be retrieved from its
resource. One use of this is to create templates that do not exist
on-the-fly.
using the default template handler function
_write_file($resource_name,$template_source);
return true;
}
} else {
// not a file
return false;
}
}
// set the default handler
$smarty->default_template_handler_func = 'make_template';
?>
]]>