Template Settings and the $tplSetting object

Starting with Zen Cart v2.0.0 there is a $tplSetting object which can be used to access site configuration settings that are customized to a specific template.

This means you can have the usual global settings configured in the Admin as usual, but allow for template-specific overrides which only take effect when a certain template is used.

One benefit of this for both storeowners and developers is the ability to try out a new template without destroying the existing configuration settings, so that your live site can function normally even while you’re experimenting with new things.

It also allows template authors to distribute configuration settings with their template, without those settings messing with a store’s already-configured settings.

NOTE: This can be used in tandem with the init_site_specific_non_db_settings.php feature available since Zen Cart v1.5.8 - see Site Specific Overrides.

Requirements

There are two requirements, using Zen Cart v2.0.0 or newer:

• the template must use $tplSetting to access settings instead of directly referring to the global CONSTANT
• the template’s /includes/templates/YOUR_TEMPLATE_NAME/template_settings.php file must contain the override settings. (See the 2 kinds of overrides, explained below)

Two Kinds of Settings Available

1. Overriding a CONSTANT such as an admin configuration setting

Many site configuration settings used by templates (and modules that supply data to templates) are controlled via the Admin configuration pages.

Here’s an example of how to override the setting by making an adjustment to your template file and defining the override separately for each template which desires to use something other than the Admin configuration setting.

Example: Banner Group #2

Zen Cart’s banner feature can be used to show in-site ads or offsite ads or other messages to customers. Some templates use the feature to control a gallery/slider-effect of images.

Banners are rendered in various positions of the template, and it’s possible that one template wants the feature turned off completely, but another template leverages it specifically. This is a good time to use template-specific settings.

1. Determine the CONSTANT that is used in the Admin for accessing the configured value. The Developers Toolkit can be useful here. If looking in the database at the configuration table, it’s the configuration_key that we’re looking for, because a CONSTANT is declared for the configuration_key, with its value set to what’s stored in configuration_value.

In the case of our example, we’re looking at the controls for SHOW_BANNERS_GROUP_SET2.

2. Replace the constant with $tplSetting->foo in the template.

Look in your template files for wherever that SHOW_BANNERS_GROUP_SET2 constant is used, and replace the constant with a reference to $tplSetting->foo where foo is that constant.

eg:

  if (SHOW_BANNERS_GROUP_SET2 != '' && $banner = zen_banner_exists('dynamic', SHOW_BANNERS_GROUP_SET2)) {

becomes the following, where two replacements are made:

  if ($tplSetting->SHOW_BANNERS_GROUP_SET2 != '' && $banner = zen_banner_exists('dynamic', $tplSetting->SHOW_BANNERS_GROUP_SET2)) {

To test, things should work as they did before, without any change yet because we haven’t configured an override setting yet. We’ll do that next:

3. Set the new value into the $tpl_settings array in template_settings.php:

In your template’s template_settings.php file, find the list of array entries for $tpl_settings, and add one for the setting you’re overriding.

eg: $tpl_settings['SHOW_BANNERS_GROUP_SET2'] = 'current_promotions';

You can now refresh the template page in your browser, and the new banner group will be applied. (Of course, you will have to have already defined a banner group by the name you’re using here. If the banner group exists and banners are assigned to it, they will be displayed.)

2. Defining a public variable that is used someplace in a template or module file.

Sometimes templates or modules are coded to be alert to the pre-existence of a variable that could be overridden by setting it earlier in the PHP code execution process.

Defining such variables is sometimes referred to as a “soft” setting/override.

Example:

The product_listing.php module has the ability to specify some CSS classes that should be applied to the grid used when in “fluid” mode (where Product Listing Columns Per Row is set to ‘0’).

If your template doesn’t need to customize anything other than the CSS style class names for the product-listing to display as desired, you could define those classes in template_settings.php instead of creating an override module file and directory for product_listing.php.

The responsive_classic template sets the following variables in its template_settings.php file to define those CSS classes:

$grid_product_cards_classes = 'row row-clmns-3';
$grid_product_classes_matrix = [
    '480' => 'row row-clms-1 row-clms-sm-2 row-clms-md-3 row-clms-lg-4 row-clms-xl-6',
];

Potential Conflicts

Be aware that if you are setting any of these public/“soft” variables using the site-specific-settings, there might be a clash. See the Technical Information For Developers section below for troubleshooting clashes.

Using template_settings in tandem with init_site_specific_non_db_settings.php

It is recommended to put template-specific settings into the template_settings.php file.

You may leave your preferred site-wide defaults as variables in init_site_specific_non_db_settings.php, but they will be overridden by template_settings.php when it is loaded.

This can work in your favor.

Technical Information for Developers

About the $tplSetting helper object

Lookup Order

The $tplSetting object looks for a value to return using this order:

1. The global $tpl_settings array for a key matching the $setting requested. (It loads that array upon instantiation.)
2. A defined CONSTANT matching the $setting requested
3. If nothing is found, null is returned

Casting types

The $tplSetting object allows you to set a type to cast each setting to upon return.

eg: ACCOUNT_STATE_DRAW_INITIAL_DROPDOWN is an admin configuration setting, stored as a string.

So echo $tplSetting->ACCOUNT_STATE_DRAW_INITIAL_DROPDOWN; would normally return 'false' as a string.

But if we set it to boolean, like this: $tplSetting->setType('ACCOUNT_STATE_DRAW_INITIAL_DROPDOWN', 'bool');

then echo $tplSetting->ACCOUNT_STATE_DRAW_INITIAL_DROPDOWN; returns false as a boolean.

Combining types and values in $tpl_settings[] array

The basic use of the $tpl_settings array lets you establish values to return when a specific key is referenced.

But if you want to also specify how to cast those values into a certain PHP type without manually calling ->setType() on each one, you can declare them in the initial $tpl_settings array as nested values of value and type (see example below). The $tplSetting` object will look for this nested-array format and use it automatically if the array keys match, instead of treating the setting as an array.

Example:

$tpl_settings['GET_VALUE_OF_TWO'] = '2';
// $tplSetting->GET_VALUE_OF_TWO will return the string '2'.

$tpl_settings['GET_VALUE_OF_TWO'] = [
    'value' => '2',
    'type' => 'int',
    ];
// $tplSetting->GET_VALUE_OF_TWO will return the integer 2.

Load Order

Zen Cart loads certain features/settings in a prescribed order. If you have a setting defined earlier in the process, it will be overridden if something else defines the same thing later on.

Also, due to the way PHP works, any CONSTANTs you’ve defined earlier in the process will NOT be overridden/definable later in the process, since they can only be defined once.

Related init-system load-order information:

• extra_datafiles including site_specific_overrides before breakpoint 0
• db CONSTANTs (admin-defined config settings) at breakpoint 40
• non-db CONSTANTs and variables in init_non_db_settings and init_site_specific_non_db_settings.php at breakpoint 45
• functions and extra_functions files at breakpoint 60
• template_settings.php at breakpoint 110
• followed by language-defines and extra_definitions for the current language