DataListItemAdd.php

<?php

namespace Drupal\rules\Plugin\RulesAction;

use Drupal\rules\Core\RulesActionBase;

/**
 * Provides an 'Add list item' action.
 *
 * @todo Add access callback information from Drupal 7?
 *
 * @RulesAction(
 *   id = "rules_list_item_add",
 *   label = @Translation("Add list item"),
 *   category = @Translation("Data"),
 *   context_definitions = {
 *     "list" = @ContextDefinition("list",
 *       label = @Translation("List"),
 *       description = @Translation("The data list, to which an item is to be added."),
 *       assignment_restriction = "selector"
 *     ),
 *     "item" = @ContextDefinition("any",
 *       label = @Translation("Item"),
 *       description = @Translation("Item to add.")
 *     ),
 *     "unique" = @ContextDefinition("boolean",
 *       label = @Translation("Enforce uniqueness"),
 *       description = @Translation("Only add the item to the list if it is not yet contained."),
 *       options_provider = "\Drupal\rules\TypedData\Options\YesNoOptions",
 *       default_value = FALSE,
 *       required = FALSE
 *     ),
 *     "position" = @ContextDefinition("string",
 *       label = @Translation("Insert position"),
 *       description = @Translation("Position to insert the item."),
 *       options_provider = "\Drupal\rules\TypedData\Options\ListPositionOptions",
 *       default_value = "end",
 *       required = FALSE
 *     ),
 *   }
 * )
 */
class DataListItemAdd extends RulesActionBase {
    
    /**
     * Add an item to a list.
     *
     * @param array $list
     *   A list to which an item is added.
     * @param mixed $item
     *   An item being added to the list.
     * @param bool $unique
     *   (optional) Whether or not we can add duplicate items.
     * @param string $position
     *   (optional) Determines if item will be added at beginning or end.
     *   Allowed values:
     *   - "start": Add to beginning of the list.
     *   - "end": Add to end of the list.
     */
    protected function doExecute(array $list, $item, $unique = FALSE, $position = 'end') {
        // Optionally, only add the list item if it is not yet contained.
        if (!((bool) $unique && in_array($item, $list))) {
            if ($position === 'start') {
                array_unshift($list, $item);
            }
            else {
                $list[] = $item;
            }
        }
        $this->setContextValue('list', $list);
    }

}