The Configuration storage

The greeting text is currently written right in the code, and the shop owner cannot change it. Module settings are kept by the Configuration class — key-value pairs in the ps_configuration database table. The core itself uses the same storage.

Writing and reading

Configuration::updateValue('ACMEHELLO_GREETING', 'Welcome!');
 
$greeting = Configuration::get('ACMEHELLO_GREETING');

updateValue() creates a value or replaces the existing one. get() returns it as a string, or false if the key does not exist.

A key is written in capital letters and starts with the module name — this way it does not clash with someone else's. The key length is up to 254 characters.

A default value on install

A setting is created in install() and removed in uninstall():

// modules/acmehello/acmehello.php
public function install(): bool
{
    return parent::install()
        && $this->registerHook('displayHome')
        && $this->registerHook('displayFooterProduct')
        && $this->registerHook('actionValidateOrder')
        && $this->registerHook('actionFrontControllerSetMedia')
        && Configuration::updateValue('ACMEHELLO_GREETING', 'Welcome!');
}
 
public function uninstall(): bool
{
    return Configuration::deleteByName('ACMEHELLO_GREETING')
        && parent::uninstall();
}

After the module is removed, none of its rows stay in the database.

Using it in a hook

// modules/acmehello/acmehello.php
public function hookDisplayHome(array $params): string
{
    $this->context->smarty->assign([
        'greeting' => Configuration::get('ACMEHELLO_GREETING'),
    ]);
 
    return $this->fetch('module:acmehello/views/templates/hook/home.tpl');
}

Reset the module so that install() writes the value:

php bin/console prestashop:module reset acmehello

The home page looks the same, but the text now comes from the database. You can check it with a query:

SELECT name, value FROM ps_configuration WHERE name LIKE 'ACMEHELLO%';

The query returns one row with the key ACMEHELLO_GREETING and the greeting text.

Methods

Method	What it does
`Configuration::get($key)`	Reads a value
`Configuration::updateValue($key, $value)`	Writes
`Configuration::deleteByName($key)`	Deletes
`Configuration::hasKey($key)`	Checks whether the key exists
`Configuration::getMultiple([$key1, $key2])`	Reads several keys into an array

Value types

The storage holds strings. A number or a flag is cast to the right type when read:

Configuration::updateValue('ACMEHELLO_LIMIT', 5);
Configuration::updateValue('ACMEHELLO_ENABLED', 1);
 
$limit = (int) Configuration::get('ACMEHELLO_LIMIT');
$enabled = (bool) Configuration::get('ACMEHELLO_ENABLED');

An array is saved as a JSON string: json_encode() on write and json_decode() on read.

Values in several languages

If the text must differ by language, pass an array whose key is the language id:

$values = [];
 
foreach (Language::getLanguages(false) as $language) {
    $values[$language['id_lang']] = 'Welcome!';
}
 
Configuration::updateValue('ACMEHELLO_GREETING', $values);
 
$greeting = Configuration::get('ACMEHELLO_GREETING', $this->context->language->id);

The second argument of get() is the id of the language the value is needed for.

Core settings

The settings of the shop itself are read the same way.

Key	What is in it
`PS_SHOP_NAME`	The shop name
`PS_SHOP_EMAIL`	The shop email
`PS_LANG_DEFAULT`	The default language id
`PS_CURRENCY_DEFAULT`	The default currency id

Common mistake

By default Configuration::updateValue() strips HTML from the value. You save text with tags and read it back without them. For HTML pass the third argument: Configuration::updateValue('ACMEHELLO_TEXT', $html, true) — and check the value with Validate::isCleanHtml() first, so that no script gets into the settings.

Thanks for reading!