class DatabaseBackend in Drupal 8

Defines the database flood backend. This is the default Drupal backend.

Hierarchy

• class \Drupal\Core\Flood\DatabaseBackend implements FloodInterface

2 files declare their use of DatabaseBackend

FloodTest.php in core/modules/system/tests/src/Kernel/System/FloodTest.php

UserLoginHttpTest.php in core/modules/user/tests/src/Functional/UserLoginHttpTest.php

1 string reference to 'DatabaseBackend'

core.services.yml in core/core.services.yml

core/core.services.yml

1 service uses DatabaseBackend

flood in core/core.services.yml

Drupal\Core\Flood\DatabaseBackend

File

core/lib/Drupal/Core/Flood/DatabaseBackend.php, line 12

Namespace

Drupal\Core\Flood

class DatabaseBackend implements FloodInterface {

  /**
   * The database table name.
   */
  const TABLE_NAME = 'flood';

  /**
   * The database connection used to store flood event information.
   *
   * @var \Drupal\Core\Database\Connection
   */
  protected $connection;

  /**
   * The request stack.
   *
   * @var \Symfony\Component\HttpFoundation\RequestStack
   */
  protected $requestStack;

  /**
   * Construct the DatabaseBackend.
   *
   * @param \Drupal\Core\Database\Connection $connection
   *   The database connection which will be used to store the flood event
   *   information.
   * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
   *   The request stack used to retrieve the current request.
   */
  public function __construct(Connection $connection, RequestStack $request_stack) {
    $this->connection = $connection;
    $this->requestStack = $request_stack;
  }

  /**
   * {@inheritdoc}
   */
  public function register($name, $window = 3600, $identifier = NULL) {
    if (!isset($identifier)) {
      $identifier = $this->requestStack
        ->getCurrentRequest()
        ->getClientIp();
    }
    $try_again = FALSE;
    try {
      $this
        ->doInsert($name, $window, $identifier);
    } catch (\Exception $e) {
      $try_again = $this
        ->ensureTableExists();
      if (!$try_again) {
        throw $e;
      }
    }
    if ($try_again) {
      $this
        ->doInsert($name, $window, $identifier);
    }
  }

  /**
   * Inserts an event into the flood table
   *
   * @param string $name
   *   The name of an event.
   * @param int $window
   *   Number of seconds before this event expires.
   * @param string $identifier
   *   Unique identifier of the current user.
   *
   * @see \Drupal\Core\Flood\DatabaseBackend::register
   */
  protected function doInsert($name, $window, $identifier) {
    $this->connection
      ->insert(static::TABLE_NAME)
      ->fields([
      'event' => $name,
      'identifier' => $identifier,
      'timestamp' => REQUEST_TIME,
      'expiration' => REQUEST_TIME + $window,
    ])
      ->execute();
  }

  /**
   * {@inheritdoc}
   */
  public function clear($name, $identifier = NULL) {
    if (!isset($identifier)) {
      $identifier = $this->requestStack
        ->getCurrentRequest()
        ->getClientIp();
    }
    try {
      $this->connection
        ->delete(static::TABLE_NAME)
        ->condition('event', $name)
        ->condition('identifier', $identifier)
        ->execute();
    } catch (\Exception $e) {
      $this
        ->catchException($e);
    }
  }

  /**
   * {@inheritdoc}
   */
  public function isAllowed($name, $threshold, $window = 3600, $identifier = NULL) {
    if (!isset($identifier)) {
      $identifier = $this->requestStack
        ->getCurrentRequest()
        ->getClientIp();
    }
    try {
      $number = $this->connection
        ->select(static::TABLE_NAME, 'f')
        ->condition('event', $name)
        ->condition('identifier', $identifier)
        ->condition('timestamp', REQUEST_TIME - $window, '>')
        ->countQuery()
        ->execute()
        ->fetchField();
      return $number < $threshold;
    } catch (\Exception $e) {
      $this
        ->catchException($e);
      return TRUE;
    }
  }

  /**
   * {@inheritdoc}
   */
  public function garbageCollection() {
    try {
      $return = $this->connection
        ->delete(static::TABLE_NAME)
        ->condition('expiration', REQUEST_TIME, '<')
        ->execute();
    } catch (\Exception $e) {
      $this
        ->catchException($e);
    }
  }

  /**
   * Check if the flood table exists and create it if not.
   */
  protected function ensureTableExists() {
    try {
      $database_schema = $this->connection
        ->schema();
      if (!$database_schema
        ->tableExists(static::TABLE_NAME)) {
        $schema_definition = $this
          ->schemaDefinition();
        $database_schema
          ->createTable(static::TABLE_NAME, $schema_definition);
        return TRUE;
      }
    } catch (DatabaseException $e) {
      return TRUE;
    }
    return FALSE;
  }

  /**
   * Act on an exception when flood might be stale.
   *
   * If the table does not yet exist, that's fine, but if the table exists and
   * yet the query failed, then the flood is stale and the exception needs to
   * propagate.
   *
   * @param $e
   *   The exception.
   *
   * @throws \Exception
   */
  protected function catchException(\Exception $e) {
    if ($this->connection
      ->schema()
      ->tableExists(static::TABLE_NAME)) {
      throw $e;
    }
  }

  /**
   * Defines the schema for the flood table.
   *
   * @internal
   */
  public function schemaDefinition() {
    return [
      'description' => 'Flood controls the threshold of events, such as the number of contact attempts.',
      'fields' => [
        'fid' => [
          'description' => 'Unique flood event ID.',
          'type' => 'serial',
          'not null' => TRUE,
        ],
        'event' => [
          'description' => 'Name of event (e.g. contact).',
          'type' => 'varchar_ascii',
          'length' => 64,
          'not null' => TRUE,
          'default' => '',
        ],
        'identifier' => [
          'description' => 'Identifier of the visitor, such as an IP address or hostname.',
          'type' => 'varchar_ascii',
          'length' => 128,
          'not null' => TRUE,
          'default' => '',
        ],
        'timestamp' => [
          'description' => 'Timestamp of the event.',
          'type' => 'int',
          'not null' => TRUE,
          'default' => 0,
        ],
        'expiration' => [
          'description' => 'Expiration timestamp. Expired events are purged on cron run.',
          'type' => 'int',
          'not null' => TRUE,
          'default' => 0,
        ],
      ],
      'primary key' => [
        'fid',
      ],
      'indexes' => [
        'allow' => [
          'event',
          'identifier',
          'timestamp',
        ],
        'purge' => [
          'expiration',
        ],
      ],
    ];
  }

}

Members

Name	Modifiers	Type	Description	Overrides
DatabaseBackend::$connection	protected	property	The database connection used to store flood event information.
DatabaseBackend::$requestStack	protected	property	The request stack.
DatabaseBackend::catchException	protected	function	Act on an exception when flood might be stale.
DatabaseBackend::clear	public	function	Makes the flood control mechanism forget an event for the current visitor. Overrides FloodInterface::clear
DatabaseBackend::doInsert	protected	function	Inserts an event into the flood table
DatabaseBackend::ensureTableExists	protected	function	Check if the flood table exists and create it if not.
DatabaseBackend::garbageCollection	public	function	Cleans up expired flood events. This method is called automatically on cron run. Overrides FloodInterface::garbageCollection
DatabaseBackend::isAllowed	public	function	Checks whether a user is allowed to proceed with the specified event. Overrides FloodInterface::isAllowed
DatabaseBackend::register	public	function	Registers an event for the current visitor to the flood control mechanism. Overrides FloodInterface::register
DatabaseBackend::schemaDefinition	public	function	Defines the schema for the flood table.
DatabaseBackend::TABLE_NAME		constant	The database table name.
DatabaseBackend::__construct	public	function	Construct the DatabaseBackend.