MachineName.php

<?php

namespace Drupal\migrate\Plugin\migrate\process;

use Drupal\Component\Transliteration\TransliterationInterface;
use Drupal\Core\Language\LanguageInterface;
use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
use Drupal\migrate\Attribute\MigrateProcess;
use Drupal\migrate\ProcessPluginBase;
use Drupal\migrate\MigrateExecutableInterface;
use Drupal\migrate\MigrateException;
use Drupal\migrate\Row;
use Symfony\Component\DependencyInjection\ContainerInterface;

/**
 * Creates a machine name.
 *
 * The machine_name process plugin takes the source value and turns it into a
 * machine-readable name via the following four steps:
 * 1. Language decorations and accents are removed by transliterating the source
 *    value.
 * 2. The resulting value is made lowercase.
 * 3. Any special characters are replaced with an underscore. By default,
 *    anything that is not a number or a letter is replaced, but additional
 *    characters can be allowed or further restricted by using the
 *    replace_pattern configuration as described below.
 * 4. Any duplicate underscores either in the source value or as a result of
 *    replacing special characters are removed.
 *
 * Available configuration keys:
 *   - replace_pattern: (optional) A custom regular expression pattern to
 *     replace special characters with an underscore using preg_replace(). This
 *     can be used to allow additional characters in the machine name.
 *     Defaults to /[^a-z0-9_]+/
 *
 * Example:
 *
 * @code
 * process:
 *   bar:
 *     plugin: machine_name
 *     source: foo
 * @endcode
 *
 * If the value of foo in the source is 'áéí!' then the destination value of bar
 * will be 'aei_'.
 *
 * @code
 * process:
 *   bar:
 *     plugin: machine_name
 *     source: foo
 *     replace_pattern: '/[^a-z0-9_.]+/'
 * @endcode
 *
 * Here the replace pattern does not match the '.' character (as it is included
 * in the list of characters not to match) so if the value of foo in the source
 * is 'áéí!.jpg' then the destination value of bar will be 'aei_.jpg'.
 *
 * @see \Drupal\migrate\Plugin\MigrateProcessInterface
 */
class MachineName extends ProcessPluginBase implements ContainerFactoryPluginInterface {
    
    /**
     * The transliteration service.
     *
     * @var \Drupal\Component\Transliteration\TransliterationInterface
     */
    protected $transliteration;
    
    /**
     * The regular expression pattern.
     *
     * @var string
     */
    protected $replacePattern;
    
    /**
     * Constructs a MachineName plugin.
     *
     * @param array $configuration
     *   The plugin configuration.
     * @param string $plugin_id
     *   The plugin ID.
     * @param mixed $plugin_definition
     *   The plugin definition.
     * @param \Drupal\Component\Transliteration\TransliterationInterface $transliteration
     *   The transliteration service.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, TransliterationInterface $transliteration) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->transliteration = $transliteration;
        $this->replacePattern = $this->configuration['replace_pattern'] ?? '/[^a-z0-9_]+/';
        if (!is_string($this->replacePattern)) {
            throw new MigrateException('The replace pattern should be a string');
        }
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('transliteration'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
        $new_value = $this->transliteration
            ->transliterate($value, LanguageInterface::LANGCODE_DEFAULT, '_');
        $new_value = strtolower($new_value);
        $new_value = preg_replace($this->replacePattern, '_', $new_value);
        return preg_replace('/_+/', '_', $new_value);
    }

}