class Flatten in Drupal 10

Flattens the source value.

The flatten process plugin converts a nested array into a flat array. For example [[1, 2, [3, 4]], [5], 6] becomes [1, 2, 3, 4, 5, 6]. During some types of processing (e.g. user permission splitting), what was once a one-dimensional array gets transformed into a multidimensional array. This plugin will flatten them back down to one-dimensional arrays again.

Example:

process:
  tags:
     -
       plugin: default_value
       source: foo
       default_value: [bar, [alpha, beta]]
     -
       plugin: flatten

In this example, the default_value process returns [bar, [alpha, beta]] (given a NULL value of foo). At this point, Migrate would try to import two items: bar and [alpha, beta]. The latter is not a valid one and won't be imported. We need to pass the values through the flatten processor to obtain a three items array [bar, alpha, beta], suitable for import.

Plugin annotation

@MigrateProcessPlugin(
  id = "flatten",
  handle_multiples = TRUE
)

Hierarchy

• class \Drupal\Component\Plugin\PluginBase implements DerivativeInspectionInterface, PluginInspectionInterface
  • class \Drupal\Core\Plugin\PluginBase uses DependencySerializationTrait, MessengerTrait, StringTranslationTrait
    • class \Drupal\migrate\ProcessPluginBase implements MigrateProcessInterface
      • class \Drupal\migrate\Plugin\migrate\process\Flatten

See also

\Drupal\migrate\Plugin\MigrateProcessInterface

1 file declares its use of Flatten

FlattenTest.php in core/modules/migrate/tests/src/Unit/process/FlattenTest.php

File

core/modules/migrate/src/Plugin/migrate/process/Flatten.php, line 45

Namespace

Drupal\migrate\Plugin\migrate\process

class Flatten extends ProcessPluginBase {

  /**
   * Flatten nested array values to single array values.
   *
   * For example, [[1, 2, [3, 4]]] becomes [1, 2, 3, 4].
   */
  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
    if (!is_array($value) && !is_object($value)) {
      $type = gettype($value);
      throw new MigrateException(sprintf("Input should be an array or an object, instead it was of type '%s'", $type));
    }
    return iterator_to_array(new \RecursiveIteratorIterator(new \RecursiveArrayIterator($value)), FALSE);
  }

}

Members

Name	Modifiers	Type	Description	Overrides
DependencySerializationTrait::$_entityStorages	protected	property
DependencySerializationTrait::$_serviceIds	protected	property
DependencySerializationTrait::__sleep	public	function		2
DependencySerializationTrait::__wakeup	public	function		2
Flatten::transform	public	function	Flatten nested array values to single array values. Overrides ProcessPluginBase::transform
MessengerTrait::$messenger	protected	property	The messenger.	18
MessengerTrait::messenger	public	function	Gets the messenger.	18
MessengerTrait::setMessenger	public	function	Sets the messenger.
PluginBase::$configuration	protected	property	Configuration information passed into the plugin.	1
PluginBase::$pluginDefinition	protected	property	The plugin implementation definition.
PluginBase::$pluginId	protected	property	The plugin_id.
PluginBase::DERIVATIVE_SEPARATOR		constant	A string which is used to separate base plugin IDs from the derivative ID.
PluginBase::getBaseId	public	function
PluginBase::getDerivativeId	public	function
PluginBase::getPluginDefinition	public	function		2
PluginBase::getPluginId	public	function
PluginBase::isConfigurable	public	function	Determines if the plugin is configurable.
PluginBase::__construct	public	function	Constructs a \Drupal\Component\Plugin\PluginBase object.	53
ProcessPluginBase::multiple	public	function	Indicates whether the returned value requires multiple handling. Overrides MigrateProcessInterface::multiple	3
StringTranslationTrait::$stringTranslation	protected	property	The string translation service.	3
StringTranslationTrait::formatPlural	protected	function	Formats a string containing a count of items.
StringTranslationTrait::getNumberOfPlurals	protected	function	Returns the number of plurals supported by a given language.
StringTranslationTrait::getStringTranslation	protected	function	Gets the string translation service.
StringTranslationTrait::setStringTranslation	public	function	Sets the string translation service to use.	1
StringTranslationTrait::t	protected	function	Translates a string to the current language or to a given language.