Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\user;
Chris@0: 
Chris@0: use Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface;
Chris@0: use Drupal\Core\Lock\LockBackendInterface;
Chris@0: use Symfony\Component\HttpFoundation\RequestStack;
Chris@0: 
Chris@0: /**
Chris@0:  * Stores and retrieves temporary data for a given owner.
Chris@0:  *
Chris@0:  * A SharedTempStore can be used to make temporary, non-cache data available
Chris@0:  * across requests. The data for the SharedTempStore is stored in one key/value
Chris@0:  * collection. SharedTempStore data expires automatically after a given
Chris@0:  * timeframe.
Chris@0:  *
Chris@0:  * The SharedTempStore is different from a cache, because the data in it is not
Chris@0:  * yet saved permanently and so it cannot be rebuilt. Typically, the
Chris@0:  * SharedTempStore might be used to store work in progress that is later saved
Chris@0:  * permanently elsewhere, e.g. autosave data, multistep forms, or in-progress
Chris@0:  * changes to complex configuration that are not ready to be saved.
Chris@0:  *
Chris@0:  * Each SharedTempStore belongs to a particular owner (e.g. a user, session, or
Chris@0:  * process). Multiple owners may use the same key/value collection, and the
Chris@0:  * owner is stored along with the key/value pair.
Chris@0:  *
Chris@0:  * Every key is unique within the collection, so the SharedTempStore can check
Chris@0:  * whether a particular key is already set by a different owner. This is
Chris@0:  * useful for informing one owner that the data is already in use by another;
Chris@0:  * for example, to let one user know that another user is in the process of
Chris@0:  * editing certain data, or even to restrict other users from editing it at
Chris@0:  * the same time. It is the responsibility of the implementation to decide
Chris@0:  * when and whether one owner can use or update another owner's data.
Chris@0:  *
Chris@0:  * If you want to be able to ensure that the data belongs to the current user,
Chris@0:  * use \Drupal\user\PrivateTempStore.
Chris@0:  */
Chris@0: class SharedTempStore {
Chris@0: 
Chris@0:   /**
Chris@0:    * The key/value storage object used for this data.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface
Chris@0:    */
Chris@0:   protected $storage;
Chris@0: 
Chris@0:   /**
Chris@0:    * The lock object used for this data.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Lock\LockBackendInterface
Chris@0:    */
Chris@0:   protected $lockBackend;
Chris@0: 
Chris@0:   /**
Chris@0:    * The request stack.
Chris@0:    *
Chris@0:    * @var \Symfony\Component\HttpFoundation\RequestStack
Chris@0:    */
Chris@0:   protected $requestStack;
Chris@0: 
Chris@0:   /**
Chris@0:    * The owner key to store along with the data (e.g. a user or session ID).
Chris@0:    *
Chris@0:    * @var mixed
Chris@0:    */
Chris@0:   protected $owner;
Chris@0: 
Chris@0:   /**
Chris@0:    * The time to live for items in seconds.
Chris@0:    *
Chris@0:    * By default, data is stored for one week (604800 seconds) before expiring.
Chris@0:    *
Chris@0:    * @var int
Chris@0:    */
Chris@0:   protected $expire;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a new object for accessing data from a key/value store.
Chris@0:    *
Chris@0:    * @param KeyValueStoreExpirableInterface $storage
Chris@0:    *   The key/value storage object used for this data. Each storage object
Chris@0:    *   represents a particular collection of data and will contain any number
Chris@0:    *   of key/value pairs.
Chris@0:    * @param \Drupal\Core\Lock\LockBackendInterface $lock_backend
Chris@0:    *   The lock object used for this data.
Chris@0:    * @param mixed $owner
Chris@0:    *   The owner key to store along with the data (e.g. a user or session ID).
Chris@0:    * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
Chris@0:    *   The request stack.
Chris@0:    * @param int $expire
Chris@0:    *   The time to live for items, in seconds.
Chris@0:    */
Chris@0:   public function __construct(KeyValueStoreExpirableInterface $storage, LockBackendInterface $lock_backend, $owner, RequestStack $request_stack, $expire = 604800) {
Chris@0:     $this->storage = $storage;
Chris@0:     $this->lockBackend = $lock_backend;
Chris@0:     $this->owner = $owner;
Chris@0:     $this->requestStack = $request_stack;
Chris@0:     $this->expire = $expire;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Retrieves a value from this SharedTempStore for a given key.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to retrieve.
Chris@0:    *
Chris@0:    * @return mixed
Chris@0:    *   The data associated with the key, or NULL if the key does not exist.
Chris@0:    */
Chris@0:   public function get($key) {
Chris@0:     if ($object = $this->storage->get($key)) {
Chris@0:       return $object->data;
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Retrieves a value from this SharedTempStore for a given key.
Chris@0:    *
Chris@0:    * Only returns the value if the value is owned by $this->owner.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to retrieve.
Chris@0:    *
Chris@0:    * @return mixed
Chris@0:    *   The data associated with the key, or NULL if the key does not exist.
Chris@0:    */
Chris@0:   public function getIfOwner($key) {
Chris@0:     if (($object = $this->storage->get($key)) && ($object->owner == $this->owner)) {
Chris@0:       return $object->data;
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Stores a particular key/value pair only if the key doesn't already exist.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to check and store.
Chris@0:    * @param mixed $value
Chris@0:    *   The data to store.
Chris@0:    *
Chris@0:    * @return bool
Chris@0:    *   TRUE if the data was set, or FALSE if it already existed.
Chris@0:    */
Chris@0:   public function setIfNotExists($key, $value) {
Chris@0:     $value = (object) [
Chris@0:       'owner' => $this->owner,
Chris@0:       'data' => $value,
Chris@0:       'updated' => (int) $this->requestStack->getMasterRequest()->server->get('REQUEST_TIME'),
Chris@0:     ];
Chris@0:     return $this->storage->setWithExpireIfNotExists($key, $value, $this->expire);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Stores a particular key/value pair in this SharedTempStore.
Chris@0:    *
Chris@0:    * Only stores the given key/value pair if it does not exist yet or is owned
Chris@0:    * by $this->owner.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to store.
Chris@0:    * @param mixed $value
Chris@0:    *   The data to store.
Chris@0:    *
Chris@0:    * @return bool
Chris@0:    *   TRUE if the data was set, or FALSE if it already exists and is not owned
Chris@0:    *   by $this->user.
Chris@0:    *
Chris@0:    * @throws \Drupal\user\TempStoreException
Chris@0:    *   Thrown when a lock for the backend storage could not be acquired.
Chris@0:    */
Chris@0:   public function setIfOwner($key, $value) {
Chris@0:     if ($this->setIfNotExists($key, $value)) {
Chris@0:       return TRUE;
Chris@0:     }
Chris@0: 
Chris@0:     if (($object = $this->storage->get($key)) && ($object->owner == $this->owner)) {
Chris@0:       $this->set($key, $value);
Chris@0:       return TRUE;
Chris@0:     }
Chris@0: 
Chris@0:     return FALSE;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Stores a particular key/value pair in this SharedTempStore.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to store.
Chris@0:    * @param mixed $value
Chris@0:    *   The data to store.
Chris@0:    *
Chris@0:    * @throws \Drupal\user\TempStoreException
Chris@0:    *   Thrown when a lock for the backend storage could not be acquired.
Chris@0:    */
Chris@0:   public function set($key, $value) {
Chris@0:     if (!$this->lockBackend->acquire($key)) {
Chris@0:       $this->lockBackend->wait($key);
Chris@0:       if (!$this->lockBackend->acquire($key)) {
Chris@0:         throw new TempStoreException("Couldn't acquire lock to update item '$key' in '{$this->storage->getCollectionName()}' temporary storage.");
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     $value = (object) [
Chris@0:       'owner' => $this->owner,
Chris@0:       'data' => $value,
Chris@0:       'updated' => (int) $this->requestStack->getMasterRequest()->server->get('REQUEST_TIME'),
Chris@0:     ];
Chris@0:     $this->storage->setWithExpire($key, $value, $this->expire);
Chris@0:     $this->lockBackend->release($key);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the metadata associated with a particular key/value pair.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to store.
Chris@0:    *
Chris@0:    * @return mixed
Chris@0:    *   An object with the owner and updated time if the key has a value, or
Chris@0:    *   NULL otherwise.
Chris@0:    */
Chris@0:   public function getMetadata($key) {
Chris@0:     // Fetch the key/value pair and its metadata.
Chris@0:     $object = $this->storage->get($key);
Chris@0:     if ($object) {
Chris@0:       // Don't keep the data itself in memory.
Chris@0:       unset($object->data);
Chris@0:       return $object;
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Deletes data from the store for a given key and releases the lock on it.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to delete.
Chris@0:    *
Chris@0:    * @throws \Drupal\user\TempStoreException
Chris@0:    *   Thrown when a lock for the backend storage could not be acquired.
Chris@0:    */
Chris@0:   public function delete($key) {
Chris@0:     if (!$this->lockBackend->acquire($key)) {
Chris@0:       $this->lockBackend->wait($key);
Chris@0:       if (!$this->lockBackend->acquire($key)) {
Chris@0:         throw new TempStoreException("Couldn't acquire lock to delete item '$key' from {$this->storage->getCollectionName()} temporary storage.");
Chris@0:       }
Chris@0:     }
Chris@0:     $this->storage->delete($key);
Chris@0:     $this->lockBackend->release($key);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Deletes data from the store for a given key and releases the lock on it.
Chris@0:    *
Chris@0:    * Only delete the given key if it is owned by $this->owner.
Chris@0:    *
Chris@0:    * @param string $key
Chris@0:    *   The key of the data to delete.
Chris@0:    *
Chris@0:    * @return bool
Chris@0:    *   TRUE if the object was deleted or does not exist, FALSE if it exists but
Chris@0:    *   is not owned by $this->owner.
Chris@0:    *
Chris@0:    * @throws \Drupal\user\TempStoreException
Chris@0:    *   Thrown when a lock for the backend storage could not be acquired.
Chris@0:    */
Chris@0:   public function deleteIfOwner($key) {
Chris@0:     if (!$object = $this->storage->get($key)) {
Chris@0:       return TRUE;
Chris@0:     }
Chris@0:     elseif ($object->owner == $this->owner) {
Chris@0:       $this->delete($key);
Chris@0:       return TRUE;
Chris@0:     }
Chris@0: 
Chris@0:     return FALSE;
Chris@0:   }
Chris@0: 
Chris@0: }