class ChainedStorage in Supercache 8

Defines a chained key value storage that uses any cache backend on top of the database default key/value storage.

This cache backend MUST be a centralized one such as Couchbase, or something that coordinates invalidations such as ChainedFast.

Hierarchy

• class \Drupal\Core\KeyValueStore\StorageBase implements KeyValueStoreInterface
  • class \Drupal\Core\KeyValueStore\DatabaseStorage uses DependencySerializationTrait
    • class \Drupal\supercache\KeyValueStore\ChainedStorage implements KeyValueStoreInterface uses ChainedStorageTrait

File

src/KeyValueStore/ChainedStorage.php, line 33

Contains \Drupal\supercache\KeyValueStore\ChainedStorage;

Namespace

Drupal\supercache\KeyValueStore

class ChainedStorage extends KeyValueDatabaseStorage implements KeyValueStoreInterface {
  use ChainedStorageTrait;

  /**
   * Overrides Drupal\Core\KeyValueStore\StorageBase::__construct().
   *
   * @param CacheFactoryInterface $factory
   *   The cache backend factory.
   * @param string $collection
   *   The name of the collection holding key and value pairs.
   * @param \Drupal\Component\Serialization\SerializationInterface $serializer
   *   The serialization class to use.
   * @param \Drupal\Core\Database\Connection $connection
   *   The database connection to use.
   * @param string $table
   *   The name of the SQL table to use, defaults to key_value.
   */
  public function __construct(CacheFactoryInterface $factory, $collection, SerializationInterface $serializer, Connection $connection, $table = 'key_value') {
    parent::__construct($collection, $serializer, $connection, $table);

    // Make sure the collection name passed to the cache factory
    // does not have any dots, or else if using database storage it will
    // crash.
    $sanitized_collection = preg_replace('/[^A-Za-z0-9_]+/', '_', $collection);
    $this->cache = $factory
      ->get($table . '_' . $sanitized_collection);
  }

  /**
   * {@inheritdoc}
   */
  public function has($key) {
    if ($cache = $this->cache
      ->get($key)) {
      if (!empty($this
        ->CacheToKeyValue([
        $cache,
      ]))) {
        return TRUE;
      }
    }

    // The fact that it does not exist in the cache
    // does not mean it does not exist in the database.
    return parent::has($key);
  }

  /**
   * {@inheritdoc}
   */
  public function getMultiple(array $keys) {
    $cached = [];
    if ($cache = $this->cache
      ->getMultiple($keys)) {
      $cached = $this
        ->CacheToKeyValue($cache);
    }
    $persisted = [];
    if (!empty($keys)) {
      $persisted = parent::getMultiple($keys);
      if (!empty($persisted)) {
        $this->cache
          ->setMultiple($this
          ->KeyValueToCache($persisted));
      }
      $this
        ->populateMissingValuesLocal($keys, $persisted);
    }
    $result = array_merge($cached, $persisted);
    return $result;
  }

  /**
   * {@inheritdoc}
   */
  public function getAll() {

    // We have to rely on the persistent
    // storage because we cannot rely
    // on the cache layer to have all
    // the key/value pairs.
    $result = parent::getAll();

    // Do not call set multiple here to prepopulate the cache
    // because it will INVALIDATE the binary on ChainedFast
    // $this->cache->setMultiple($this->KeyValueToCache($result));
    return $result;
  }

  /**
   * {@inheritdoc}
   */
  public function set($key, $value) {
    $this->cache
      ->set($key, $value);
    parent::set($key, $value);
  }

  /**
   * {@inheritdoc}
   */
  public function setIfNotExists($key, $value) {
    $result = parent::setIfNotExists($key, $value);
    if ($result == Merge::STATUS_INSERT) {
      $this->cache
        ->set($key, $value);
    }
    return $result;
  }

  /**
   * {@inheritdoc}
   */
  public function rename($key, $new_key) {
    parent::rename($key, $new_key);
    $this->cache
      ->delete($key);
  }

  /**
   * {@inheritdoc}
   */
  public function deleteMultiple(array $keys) {
    parent::deleteMultiple($keys);
    $this->cache
      ->deleteMultiple($keys);
  }

  /**
   * {@inheritdoc}
   */
  public function deleteAll() {
    parent::deleteAll();
    $this->cache
      ->deleteAll();
  }

}

Members

Name	Modifiers	Type	Description	Overrides
ChainedStorage::deleteAll	public	function	Deletes all items from the key/value store. Overrides DatabaseStorage::deleteAll
ChainedStorage::deleteMultiple	public	function	Deletes multiple items from the key/value store. Overrides DatabaseStorage::deleteMultiple
ChainedStorage::getAll	public	function	Returns all stored key/value pairs in the collection. Overrides DatabaseStorage::getAll
ChainedStorage::getMultiple	public	function	Returns the stored key/value pairs for a given set of keys. Overrides DatabaseStorage::getMultiple
ChainedStorage::has	public	function	Returns whether a given key exists in the store. Overrides DatabaseStorage::has
ChainedStorage::rename	public	function	Renames a key. Overrides DatabaseStorage::rename
ChainedStorage::set	public	function	Saves a value for a given key. Overrides DatabaseStorage::set
ChainedStorage::setIfNotExists	public	function	Saves a value for a given key if it does not exist yet. Overrides DatabaseStorage::setIfNotExists
ChainedStorage::__construct	public	function	Overrides Drupal\Core\KeyValueStore\StorageBase::__construct(). Overrides DatabaseStorage::__construct
ChainedStorageTrait::$cache	protected	property	The cache backend.
ChainedStorageTrait::$EMPTY_VALUE	protected	property	Special value stored in the cache layer to identify missing items in the persistent cache.
ChainedStorageTrait::CacheToKeyValue	protected	function	Converts a cache array to a KeyValue array.
ChainedStorageTrait::KeyValueToCache	protected	function	Converts an array of KeyValues to a cache compatible array.
ChainedStorageTrait::populateMissingValuesLocal	protected	function	To prevent database lookups we store a special 'empty' object.
DatabaseStorage::$connection	protected	property	The database connection.
DatabaseStorage::$serializer	protected	property	The serialization class to use.
DatabaseStorage::$table	protected	property	The name of the SQL table to use.
DependencySerializationTrait::$_entityStorages	protected	property	An array of entity type IDs keyed by the property name of their storages.
DependencySerializationTrait::$_serviceIds	protected	property	An array of service IDs keyed by property name used for serialization.
DependencySerializationTrait::__sleep	public	function		1
DependencySerializationTrait::__wakeup	public	function		2
StorageBase::$collection	protected	property	The name of the collection holding key and value pairs.
StorageBase::delete	public	function	Deletes an item from the key/value store. Overrides KeyValueStoreInterface::delete	1
StorageBase::get	public	function	Returns the stored value for a given key. Overrides KeyValueStoreInterface::get	1
StorageBase::getCollectionName	public	function	Returns the name of this collection. Overrides KeyValueStoreInterface::getCollectionName
StorageBase::setMultiple	public	function	Saves key/value pairs. Overrides KeyValueStoreInterface::setMultiple	1