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class MachineName in Drupal 9

Same name in this branch
  1. 9 core/lib/Drupal/Core/Render/Element/MachineName.php \Drupal\Core\Render\Element\MachineName
  2. 9 core/modules/views/src/Plugin/views/field/MachineName.php \Drupal\views\Plugin\views\field\MachineName
  3. 9 core/modules/migrate/src/Plugin/migrate/process/MachineName.php \Drupal\migrate\Plugin\migrate\process\MachineName
Same name and namespace in other branches
  1. 8 core/lib/Drupal/Core/Render/Element/MachineName.php \Drupal\Core\Render\Element\MachineName

Provides a machine name render element.

Provides a form element to enter a machine name, which is validated to ensure that the name is unique and does not contain disallowed characters.

The element may be automatically populated via JavaScript when used in conjunction with a separate "source" form element (typically specifying the human-readable name). As the user types text into the source element, the JavaScript converts all values to lower case, replaces any remaining disallowed characters with a replacement, and populates the associated machine name form element.

Properties:

  • #machine_name: An associative array containing:

    • exists: A callable to invoke for checking whether a submitted machine name value already exists. The arguments passed to the callback will be:

      • The submitted value.
      • The element array.
      • The form state object.

      In most cases, an existing API or menu argument loader function can be re-used. The callback is only invoked if the submitted value differs from the element's initial #default_value. The initial #default_value is stored in form state so AJAX forms can be reliably validated.

    • source: (optional) The #array_parents of the form element containing the human-readable name (i.e., as contained in the $form structure) to use as source for the machine name. Defaults to array('label').
    • label: (optional) Text to display as label for the machine name value after the human-readable name form element. Defaults to t('Machine name').
    • replace_pattern: (optional) A regular expression (without delimiters) matching disallowed characters in the machine name. Defaults to '[^a-z0-9_]+'.
    • replace: (optional) A character to replace disallowed characters in the machine name via JavaScript. Defaults to '_' (underscore). When using a different character, 'replace_pattern' needs to be set accordingly.
    • error: (optional) A custom form error message string to show, if the machine name contains disallowed characters.
    • standalone: (optional) Whether the live preview should stay in its own form element rather than in the suffix of the source element. Defaults to FALSE.
  • #maxlength: (optional) Maximum allowed length of the machine name. Defaults to 64.
  • #disabled: (optional) Should be set to TRUE if an existing machine name must not be changed after initial creation.

Usage example:

$form['id'] = array(
  '#type' => 'machine_name',
  '#default_value' => $this->entity
    ->id(),
  '#disabled' => !$this->entity
    ->isNew(),
  '#maxlength' => 64,
  '#description' => $this
    ->t('A unique name for this item. It must only contain lowercase letters, numbers, and underscores.'),
  '#machine_name' => array(
    'exists' => array(
      $this,
      'exists',
    ),
  ),
);

Plugin annotation

@FormElement("machine_name");

Hierarchy

Expanded class hierarchy of MachineName

See also

\Drupal\Core\Render\Element\Textfield

1 file declares its use of MachineName
MachineNameTest.php in core/tests/Drupal/Tests/Core/Render/Element/MachineNameTest.php
30 #type uses of MachineName
ActionFormBase::form in core/modules/action/src/Form/ActionFormBase.php
Gets the actual form array to be built.
BlockContentTypeForm::form in core/modules/block_content/src/BlockContentTypeForm.php
Gets the actual form array to be built.
BlockForm::form in core/modules/block/src/BlockForm.php
Gets the actual form array to be built.
CommentTypeForm::form in core/modules/comment/src/CommentTypeForm.php
Gets the actual form array to be built.
ConfigTestForm::form in core/modules/config/tests/config_test/src/ConfigTestForm.php
Gets the actual form array to be built.

... See full list

File

core/lib/Drupal/Core/Render/Element/MachineName.php, line 72

Namespace

Drupal\Core\Render\Element
View source 
class MachineName extends Textfield {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    $class = static::class;
    return [
      '#input' => TRUE,
      '#default_value' => NULL,
      '#required' => TRUE,
      '#maxlength' => 64,
      '#size' => 60,
      '#autocomplete_route_name' => FALSE,
      '#process' => [
        [
          $class,
          'processMachineName',
        ],
        [
          $class,
          'processAutocomplete',
        ],
        [
          $class,
          'processAjaxForm',
        ],
      ],
      '#element_validate' => [
        [
          $class,
          'validateMachineName',
        ],
      ],
      '#pre_render' => [
        [
          $class,
          'preRenderTextfield',
        ],
      ],
      '#theme' => 'input__textfield',
      '#theme_wrappers' => [
        'form_element',
      ],
    ];
  }

  /**
   * {@inheritdoc}
   */
  public static function valueCallback(&$element, $input, FormStateInterface $form_state) {
    if ($input !== FALSE && $input !== NULL) {

      // This should be a string, but allow other scalars since they might be
      // valid input in programmatic form submissions.
      return is_scalar($input) ? (string) $input : '';
    }
    return NULL;
  }

  /**
   * Processes a machine-readable name form element.
   *
   * @param array $element
   *   The form element to process. See main class documentation for properties.
   * @param \Drupal\Core\Form\FormStateInterface $form_state
   *   The current state of the form.
   * @param array $complete_form
   *   The complete form structure.
   *
   * @return array
   *   The processed element.
   */
  public static function processMachineName(&$element, FormStateInterface $form_state, &$complete_form) {

    // We need to pass the langcode to the client.
    $language = \Drupal::languageManager()
      ->getCurrentLanguage();

    // Apply default form element properties.
    $element += [
      '#title' => t('Machine-readable name'),
      '#description' => t('A unique machine-readable name. Can only contain lowercase letters, numbers, and underscores.'),
      '#machine_name' => [],
      '#field_prefix' => '',
      '#field_suffix' => '',
      '#suffix' => '',
    ];

    // A form element that only wants to set one #machine_name property (usually
    // 'source' only) would leave all other properties undefined, if the defaults
    // were defined by an element plugin. Therefore, we apply the defaults here.
    $element['#machine_name'] += [
      'source' => [
        'label',
      ],
      'target' => '#' . $element['#id'],
      'label' => t('Machine name'),
      'replace_pattern' => '[^a-z0-9_]+',
      'replace' => '_',
      'standalone' => FALSE,
      'field_prefix' => $element['#field_prefix'],
      'field_suffix' => $element['#field_suffix'],
    ];

    // Store the initial value in form state. The machine name needs this to
    // ensure that the exists function is not called for existing values when
    // editing them.
    $initial_values = $form_state
      ->get('machine_name.initial_values') ?: [];

    // Store the initial values in an array so we can differentiate between a
    // NULL default value and a new machine name element.
    if (!array_key_exists($element['#name'], $initial_values)) {
      $initial_values[$element['#name']] = $element['#default_value'];
      $form_state
        ->set('machine_name.initial_values', $initial_values);
    }

    // By default, machine names are restricted to Latin alphanumeric characters.
    // So, default to LTR directionality.
    if (!isset($element['#attributes'])) {
      $element['#attributes'] = [];
    }
    $element['#attributes'] += [
      'dir' => LanguageInterface::DIRECTION_LTR,
    ];

    // The source element defaults to array('name'), but may have been overridden.
    if (empty($element['#machine_name']['source'])) {
      return $element;
    }

    // Retrieve the form element containing the human-readable name from the
    // complete form in $form_state. By reference, because we may need to append
    // a #field_suffix that will hold the live preview.
    $key_exists = NULL;
    $source = NestedArray::getValue($form_state
      ->getCompleteForm(), $element['#machine_name']['source'], $key_exists);
    if (!$key_exists) {
      return $element;
    }
    $suffix_id = $source['#id'] . '-machine-name-suffix';
    $element['#machine_name']['suffix'] = '#' . $suffix_id;
    if ($element['#machine_name']['standalone']) {
      $element['#suffix'] = $element['#suffix'] . ' <small id="' . $suffix_id . '">&nbsp;</small>';
    }
    else {

      // Append a field suffix to the source form element, which will contain
      // the live preview of the machine name.
      $source += [
        '#field_suffix' => '',
      ];
      $source['#field_suffix'] = $source['#field_suffix'] . ' <small id="' . $suffix_id . '">&nbsp;</small>';
      $parents = array_merge($element['#machine_name']['source'], [
        '#field_suffix',
      ]);
      NestedArray::setValue($form_state
        ->getCompleteForm(), $parents, $source['#field_suffix']);
    }
    $element['#attached']['library'][] = 'core/drupal.machine-name';
    $options = [
      'replace_pattern',
      'replace_token',
      'replace',
      'maxlength',
      'target',
      'label',
      'field_prefix',
      'field_suffix',
      'suffix',
    ];

    /** @var \Drupal\Core\Access\CsrfTokenGenerator $token_generator */
    $token_generator = \Drupal::service('csrf_token');
    $element['#machine_name']['replace_token'] = $token_generator
      ->get($element['#machine_name']['replace_pattern']);
    $element['#attached']['drupalSettings']['machineName']['#' . $source['#id']] = array_intersect_key($element['#machine_name'], array_flip($options));
    $element['#attached']['drupalSettings']['langcode'] = $language
      ->getId();
    return $element;
  }

  /**
   * Form element validation handler for machine_name elements.
   *
   * Note that #maxlength is validated by _form_validate() already.
   *
   * This checks that the submitted value:
   * - Does not contain the replacement character only.
   * - Does not contain disallowed characters.
   * - Is unique; i.e., does not already exist.
   * - Does not exceed the maximum length (via #maxlength).
   * - Cannot be changed after creation (via #disabled).
   */
  public static function validateMachineName(&$element, FormStateInterface $form_state, &$complete_form) {

    // Verify that the machine name not only consists of replacement tokens.
    if (preg_match('@^' . $element['#machine_name']['replace'] . '+$@', $element['#value'])) {
      $form_state
        ->setError($element, t('The machine-readable name must contain unique characters.'));
    }

    // Verify that the machine name contains no disallowed characters.
    if (preg_match('@' . $element['#machine_name']['replace_pattern'] . '@', $element['#value'])) {
      if (!isset($element['#machine_name']['error'])) {

        // Since a hyphen is the most common alternative replacement character,
        // a corresponding validation error message is supported here.
        if ($element['#machine_name']['replace'] == '-') {
          $form_state
            ->setError($element, t('The machine-readable name must contain only lowercase letters, numbers, and hyphens.'));
        }
        else {
          $form_state
            ->setError($element, t('The machine-readable name must contain only lowercase letters, numbers, and underscores.'));
        }
      }
      else {
        $form_state
          ->setError($element, $element['#machine_name']['error']);
      }
    }

    // Verify that the machine name is unique. If the value matches the initial
    // default value then it does not need to be validated as the machine name
    // element assumes the form is editing the existing value.
    $initial_values = $form_state
      ->get('machine_name.initial_values') ?: [];
    if (!array_key_exists($element['#name'], $initial_values) || $initial_values[$element['#name']] !== $element['#value']) {
      $function = $element['#machine_name']['exists'];
      if (call_user_func($function, $element['#value'], $element, $form_state)) {
        $form_state
          ->setError($element, t('The machine-readable name is already in use. It must be unique.'));
      }
    }
  }

}

Members

Namesort descending Modifiers Type Description Overrides
DependencySerializationTrait::$_entityStorages protected property
DependencySerializationTrait::$_serviceIds protected property
DependencySerializationTrait::__sleep public function 2
DependencySerializationTrait::__wakeup public function 2
FormElement::processAutocomplete public static function Adds autocomplete functionality to elements.
FormElement::processPattern public static function #process callback for #pattern form element property.
FormElement::validatePattern public static function #element_validate callback for #pattern form element property.
MachineName::getInfo public function Returns the element properties for this element. Overrides Textfield::getInfo
MachineName::processMachineName public static function Processes a machine-readable name form element.
MachineName::validateMachineName public static function Form element validation handler for machine_name elements.
MachineName::valueCallback public static function Determines how user input is mapped to an element's #value property. Overrides Textfield::valueCallback
MessengerTrait::$messenger protected property The messenger. 27
MessengerTrait::messenger public function Gets the messenger. 27
MessengerTrait::setMessenger public function Sets the messenger.
PluginBase::$configuration protected property Configuration information passed into the plugin. 1
PluginBase::$pluginDefinition protected property The plugin implementation definition. 1
PluginBase::$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 Gets the base_plugin_id of the plugin instance. Overrides DerivativeInspectionInterface::getBaseId
PluginBase::getDerivativeId public function Gets the derivative_id of the plugin instance. Overrides DerivativeInspectionInterface::getDerivativeId
PluginBase::getPluginDefinition public function Gets the definition of the plugin implementation. Overrides PluginInspectionInterface::getPluginDefinition 2
PluginBase::getPluginId public function Gets the plugin_id of the plugin instance. Overrides PluginInspectionInterface::getPluginId
PluginBase::isConfigurable public function Determines if the plugin is configurable.
PluginBase::__construct public function Constructs a \Drupal\Component\Plugin\PluginBase object. 98
RenderElement::preRenderAjaxForm public static function Adds Ajax information about an element to communicate with JavaScript.
RenderElement::preRenderGroup public static function Adds members of this group as actual elements for rendering.
RenderElement::processAjaxForm public static function Form element processing handler for the #ajax form property. 1
RenderElement::processGroup public static function Arranges elements into groups.
RenderElement::setAttributes public static function Sets a form element's class attribute. Overrides ElementInterface::setAttributes
StringTranslationTrait::$stringTranslation protected property The string translation service. 4
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. 2
StringTranslationTrait::t protected function Translates a string to the current language or to a given language.
Textfield::preRenderTextfield public static function Prepares a #type 'textfield' render element for input.html.twig.