PirateDayCacheContext.php

<?php

namespace Drupal\config_override_test\Cache;

use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Cache\Context\CacheContextInterface;

/**
 * Defines the PirateDayCacheContext service that allows to cache the booty.
 *
 * Cache context ID: 'pirate_day'.
 */
class PirateDayCacheContext implements CacheContextInterface {
    
    /**
     * The length of Pirate Day. It lasts 24 hours.
     *
     * This is a simplified test implementation. In a real life Pirate Day module
     * this data wouldn't be defined in a constant, but calculated in a static
     * method. If it were Pirate Day it should return the number of seconds until
     * midnight, and on all other days it should return the number of seconds
     * until the start of the next Pirate Day.
     */
    const PIRATE_DAY_MAX_AGE = 86400;
    
    /**
     * {@inheritdoc}
     */
    public static function getLabel() {
        return t('Pirate day');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getContext() {
        $is_pirate_day = static::isPirateDay() ? 'yarr' : 'nay';
        return "pirate_day." . $is_pirate_day;
    }
    
    /**
     * Returns whether or not it is Pirate Day.
     *
     * To ease testing this is determined with a global variable rather than using
     * the traditional compass and sextant.
     *
     * @return bool
     *   Returns TRUE if it is Pirate Day today.
     */
    public static function isPirateDay() {
        return !empty($GLOBALS['it_is_pirate_day']);
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheableMetadata() {
        return new CacheableMetadata();
    }

}