class Extract

Same name and namespace in other branches
  1. 9 core/modules/migrate/src/Plugin/migrate/process/Extract.php \Drupal\migrate\Plugin\migrate\process\Extract
  2. 8.9.x core/modules/migrate/src/Plugin/migrate/process/Extract.php \Drupal\migrate\Plugin\migrate\process\Extract
  3. 10 core/modules/migrate/src/Plugin/migrate/process/Extract.php \Drupal\migrate\Plugin\migrate\process\Extract

Extracts a value from an array.

The extract process plugin is used to pull data from an input array, which may have multiple levels. One use case is extracting data from field arrays in previous versions of Drupal. For instance, in Drupal 7, a field array would be indexed first by language, then by delta, then finally a key such as 'value'.

Available configuration keys:

  • source: The input value - must be an array.
  • index: The array of keys to access the value.
  • default: (optional) A default value to assign to the destination if the key does not exist.


    plugin: extract
    source: some_text_field
      - und
      - 0
      - value

The PHP equivalent of this would be:

$destination['new_text_field'] = $source['some_text_field']['und'][0]['value'];

If a default value is specified, it will be returned if the index does not exist in the input array.

plugin: extract
source: some_text_field
default: 'Default title'
  - title

If $source['some_text_field']['title'] doesn't exist, then the plugin will return "Default title".


Expanded class hierarchy of Extract

See also


1 file declares its use of Extract
ExtractTest.php in core/modules/migrate/tests/src/Unit/process/ExtractTest.php
26 string references to 'Extract'
d6_field_formatter_settings.yml in core/modules/field/migrations/d6_field_formatter_settings.yml
d6_field_instance.yml in core/modules/field/migrations/d6_field_instance.yml
d6_field_instance_label_description_translation.yml in core/modules/config_translation/migrations/d6_field_instance_label_description_translation.yml
d6_field_instance_option_translation.yml in core/modules/config_translation/migrations/d6_field_instance_option_translation.yml
d6_field_instance_widget_settings.yml in core/modules/field/migrations/d6_field_instance_widget_settings.yml

... See full list


core/modules/migrate/src/Plugin/migrate/process/Extract.php, line 61


View source
class Extract extends ProcessPluginBase {
     * {@inheritdoc}
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        if (!is_array($value)) {
            throw new MigrateException(sprintf("Input should be an array, instead it was of type '%s'", gettype($value)));
        $new_value = NestedArray::getValue($value, $this->configuration['index'], $key_exists);
        if (!$key_exists) {
            if (array_key_exists('default', $this->configuration)) {
                $new_value = $this->configuration['default'];
            else {
                throw new MigrateException(sprintf("Array index missing, extraction failed for '%s'. Consider adding a `default` key to the configuration.", Variable::export($value)));
        return $new_value;



Title Sort descending Modifiers Object type Summary Overriden Title Overrides
Extract::transform public function Performs the associated process. Overrides ProcessPluginBase::transform
PluginInspectionInterface::getPluginDefinition public function Gets the definition of the plugin implementation. 6
PluginInspectionInterface::getPluginId public function Gets the plugin_id of the plugin instance. 2
ProcessPluginBase::$stopPipeline protected property Determines if processing of the pipeline is stopped.
ProcessPluginBase::isPipelineStopped public function Determines if the pipeline should stop processing. Overrides MigrateProcessInterface::isPipelineStopped
ProcessPluginBase::multiple public function Indicates whether the returned value requires multiple handling. Overrides MigrateProcessInterface::multiple 3
ProcessPluginBase::reset public function Resets the internal data of a plugin. Overrides MigrateProcessInterface::reset
ProcessPluginBase::stopPipeline protected function Stops pipeline processing after this plugin finishes.

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