Feature: #99048 - Site settings read API

Description

Settings for site-specific functionality can now be retrieved by a dedicated \TYPO3\CMS\Core\Site\Entity\SiteSettings object, accessible via a \TYPO3\CMS\Core\Site\Entity\Site object like $site->getSettings().

Settings can be used in custom frontend code to deliver features which might vary per-site for extensions.

Impact

Accessing site settings, which was previously possible via:

$site->getConfiguration()['settings']['redirects'] ?? []

in custom PHP code, is now easier via the SiteSettings PHP object.

The SiteSettings object can be used to access settings either by the dot notation ("flat", a default value can be given as optional second argument), e.g.:

$redirectStatusCode = (int)$siteSettings->get('redirects.httpStatusCode', 307);

or by accessing all options for a certain group:

$allSettingsRelatedToRedirects = $siteSettings->get('redirects');

or even fetching all settings:

$allSettings = $siteSettings->all();

In addition, settings can now be accessed in TypoScript via getData with the key siteSettings:

page.10 = TEXT
page.10.data = siteSettings:redirects.httpStatusCode