CookiesCacheContext.php

<?php

namespace Drupal\Core\Cache\Context;

use Drupal\Core\Cache\CacheableMetadata;

/**
 * Defines the CookiesCacheContext service, for "per cookie" caching.
 *
 * Cache context ID: 'cookies' (to vary by all cookies).
 * Calculated cache context ID: 'cookies:%name', e.g. 'cookies:device_type' (to
 * vary by the 'device_type' cookie).
 */
class CookiesCacheContext extends RequestStackCacheContextBase implements CalculatedCacheContextInterface {
    
    /**
     * {@inheritdoc}
     */
    public static function getLabel() {
        return t('HTTP cookies');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getContext($cookie = NULL) {
        if ($cookie === NULL) {
            $cookies = $this->requestStack
                ->getCurrentRequest()->cookies
                ->all();
            // Sort the cookies by names, to always set the same context if the cookies
            // are the same but in a different order.
            ksort($cookies);
            // Use http_build_query() to get a short string from the cookies array.
            return http_build_query($cookies);
        }
        else {
            return $this->requestStack
                ->getCurrentRequest()->cookies
                ->get($cookie);
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheableMetadata($cookie = NULL) {
        return new CacheableMetadata();
    }

}