SiteContext.php

<?php

namespace Drupal\rules\ContextProvider;

use Drupal\Core\Cache\CacheableMetadata;
use Drupal\Core\Config\ConfigFactoryInterface;
use Drupal\Core\Plugin\Context\Context;
use Drupal\Core\Plugin\Context\ContextDefinition;
use Drupal\Core\Plugin\Context\ContextProviderInterface;
use Drupal\Core\StringTranslation\StringTranslationTrait;
use Drupal\Core\Url;

/**
 * Sets the current node as a context on node routes.
 *
 * Modules may add properties to this global context by implementing
 * hook_data_type_info_alter(&$data_types) to modify the $data_types['site']
 * element.
 *
 * @todo Need a way to alter the global context contents to set a value for
 * any added site properties.
 */
class SiteContext implements ContextProviderInterface {
    use StringTranslationTrait;
    
    /**
     * The system.site configuration.
     *
     * @var \Drupal\Core\Config\ImmutableConfig
     */
    protected $systemSiteConfig;
    
    /**
     * Constructs a new SiteContext.
     *
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The config.factory service.
     */
    public function __construct(ConfigFactoryInterface $config_factory) {
        $this->systemSiteConfig = $config_factory->get('system.site');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getRuntimeContexts(array $unqualified_context_ids) {
        $site = [
            'url' => Url::fromRoute('<front>', [], [
                'absolute' => TRUE,
            ])->toString(),
            'login-url' => Url::fromRoute('user.page', [], [
                'absolute' => TRUE,
            ])->toString(),
            'name' => $this->systemSiteConfig
                ->get('name'),
            'slogan' => $this->systemSiteConfig
                ->get('slogan'),
            'mail' => $this->systemSiteConfig
                ->get('mail'),
        ];
        $context_definition = new ContextDefinition('site', $this->t('Site information'));
        $context = new Context($context_definition, $site);
        $cacheability = new CacheableMetadata();
        $cacheability->setCacheContexts([
            'site',
        ]);
        $context->addCacheableDependency($cacheability);
        $result = [
            'site' => $context,
        ];
        return $result;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getAvailableContexts() {
        return $this->getRuntimeContexts([]);
    }

}