class HeadersCacheContext

Same name and namespace in other branches
  1. 9 core/lib/Drupal/Core/Cache/Context/HeadersCacheContext.php \Drupal\Core\Cache\Context\HeadersCacheContext
  2. 8.9.x core/lib/Drupal/Core/Cache/Context/HeadersCacheContext.php \Drupal\Core\Cache\Context\HeadersCacheContext
  3. 10 core/lib/Drupal/Core/Cache/Context/HeadersCacheContext.php \Drupal\Core\Cache\Context\HeadersCacheContext

Defines the HeadersCacheContext service, for "per header" caching.

Cache context ID: 'headers' (to vary by all headers). Calculated cache context ID: 'headers:%name', e.g. 'headers:X-Something' (to vary by the 'X-Something' header).

Hierarchy

Expanded class hierarchy of HeadersCacheContext

1 file declares its use of HeadersCacheContext
HeadersCacheContextTest.php in core/tests/Drupal/Tests/Core/Cache/Context/HeadersCacheContextTest.php

File

core/lib/Drupal/Core/Cache/Context/HeadersCacheContext.php, line 14

Namespace

Drupal\Core\Cache\Context
View source 
class HeadersCacheContext extends RequestStackCacheContextBase implements CalculatedCacheContextInterface {
    
    /**
     * {@inheritdoc}
     */
    public static function getLabel() {
        return t('HTTP headers');
    }
    
    /**
     * {@inheritdoc}
     */
    public function getContext($header = NULL) {
        if ($header === NULL) {
            $headers = $this->requestStack
                ->getCurrentRequest()->headers
                ->all();
            // Order headers by name to have less cache variations.
            ksort($headers);
            $result = '';
            foreach ($headers as $name => $value) {
                if ($result) {
                    $result .= '&';
                }
                // Sort values to minimize cache variations.
                sort($value);
                $result .= $name . '=' . implode(',', $value);
            }
            return $result;
        }
        elseif ($this->requestStack
            ->getCurrentRequest()->headers
            ->has($header)) {
            $value = $this->requestStack
                ->getCurrentRequest()->headers
                ->get($header);
            if ($value !== '') {
                return $value;
            }
            return '?valueless?';
        }
        return '';
    }
    
    /**
     * {@inheritdoc}
     */
    public function getCacheableMetadata($header = NULL) {
        return new CacheableMetadata();
    }

}

Members

Title Modifiers Object type Summary Overriden Title
HeadersCacheContext::getCacheableMetadata public function Gets the cacheability metadata for the context based on the parameter value. Overrides CalculatedCacheContextInterface::getCacheableMetadata
HeadersCacheContext::getContext public function Returns the string representation of the cache context. Overrides CalculatedCacheContextInterface::getContext
HeadersCacheContext::getLabel public static function Returns the label of the cache context. Overrides CalculatedCacheContextInterface::getLabel
RequestStackCacheContextBase::$requestStack protected property The request stack.
RequestStackCacheContextBase::__construct public function Constructs a new RequestStackCacheContextBase class.

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