class Flood in Acquia Search 3.x

Class Flood.

A mechanism to limit the outgoing number of requests to the Acquia Search Solr backend using the Drupal Flood API.

This complements the Solr traffic limits embedded into on the Acquia platform.

This class will look at the recent requests during a time window, and return a boolean value on whether to block/allow those requests. The actual blocking happens elsewhere.

The values in code are named 'window' and 'limit. window: the amount of seconds in the "sliding window" time limit: the maximum amount of requests that can be done during that window.

So, to check whether to carry out or block the current request, we use look at the window between T-[window] seconds up to the present, and if more than [limit] requests of the same [type] have happened, we will deny that request.

Example: for limit=10 [requests] and window=10 [seconds] allows at most 10 requests in that time period.

See the Drupal Flood API documentation for more: https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Flood%21F...

Hierarchy

• class \Drupal\acquia_search\Helper\Flood

1 file declares its use of Flood

SearchSubscriber.php in src/EventSubscriber/SearchSubscriber.php

File

src/Helper/Flood.php, line 33

Namespace

Drupal\acquia_search\Helper

class Flood {

  /**
   * List of values by each Solarium request type.
   */
  public static function getFloodDefaults() {
    return [
      'select' => [
        'window' => 10,
        'limit' => 50,
      ],
      'update' => [
        'window' => 60,
        'limit' => 600,
      ],
      'update/extract' => [
        'window' => 60,
        'limit' => 600,
      ],
      'autocomplete' => [
        'window' => 10,
        'limit' => 100,
      ],
      'test' => [
        'window' => 2,
        'limit' => 1,
      ],
    ];
  }

  /**
   * Return the integer value for the specified type and option.
   *
   * @param string $request_type
   *   The incoming request type.
   * @param string $value_name
   *   The name of the type value.
   *
   * @return int
   *   Integer value for specified type and option.
   */
  public static function getConfigValue(string $request_type, string $value_name) {
    $defaults = self::getFloodDefaults();
    $escaped_request_type = str_replace('/', '_', $request_type);
    $config_id = 'flood_limit.' . $escaped_request_type . '.' . $value_name;
    return \Drupal::config('acquia_search.settings')
      ->get($config_id) ?? $defaults[$request_type][$value_name];
  }

  /**
   * Return boolean value stating if logging is enabled.
   *
   * @return bool
   *   If logging is enabled or not.
   */
  public static function isLoggingEnabled() : bool {
    return \Drupal::config('acquia_search.settings')
      ->get('flood_logging') ?? TRUE;
  }

  /**
   * Return the window for the given request type.
   *
   * @param string $request_type
   *   The incoming request type.
   */
  public static function logFloodLimit(string $request_type) {
    if (self::isLoggingEnabled()) {
      \Drupal::logger('acquia_search')
        ->warning('Flood protection has blocked request of type @id.', [
        '@id' => $request_type,
      ]);
    }
  }

  /**
   * Check that the given ID is a valid string from a list of defined values.
   *
   * @param string $request_type
   *   The incoming request type.
   *
   * @return bool
   *   If the request type is controlled
   */
  public static function isControlled(string $request_type) : bool {
    $defaults = self::getFloodDefaults();
    return isset($defaults[$request_type]);
  }

  /**
   * Determines if a request can be sent via the flood control mechanism.
   *
   * @param string $request_type
   *   The incoming request type.
   *
   * @return bool
   *   If the request is allowed
   *
   * @throws \Exception
   */
  public static function isAllowed(string $request_type) : bool {

    // Allow all requests from types that aren't controlled.
    if (!self::isControlled($request_type)) {
      return TRUE;
    }

    // Use the Drupal Flood service to check if we can run this request.
    $is_allowed = \Drupal::flood()
      ->isAllowed('acquia_search', self::getConfigValue($request_type, 'limit'), self::getConfigValue($request_type, 'window'), $request_type);

    // If this request should be blocked, log if needed and return.
    if (!$is_allowed) {
      self::logFloodLimit($request_type);
      return FALSE;
    }

    // Log the allowed request into the Flood service.
    \Drupal::flood()
      ->register('acquia_search', self::getConfigValue($request_type, 'window'), $request_type);
    return TRUE;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Flood::getConfigValue	public static	function	Return the integer value for the specified type and option.
Flood::getFloodDefaults	public static	function	List of values by each Solarium request type.
Flood::isAllowed	public static	function	Determines if a request can be sent via the flood control mechanism.
Flood::isControlled	public static	function	Check that the given ID is a valid string from a list of defined values.
Flood::isLoggingEnabled	public static	function	Return boolean value stating if logging is enabled.
Flood::logFloodLimit	public static	function	Return the window for the given request type.