class MachineName in Zircon Profile 8

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 submitted value is passed as an argument. 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 #default_value.
  • 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

• class \Drupal\Component\Plugin\PluginBase implements DerivativeInspectionInterface, PluginInspectionInterface
  • class \Drupal\Core\Plugin\PluginBase uses DependencySerializationTrait, StringTranslationTrait
    • class \Drupal\Core\Render\Element\RenderElement implements ElementInterface
      • class \Drupal\Core\Render\Element\FormElement implements FormElementInterface
        • class \Drupal\Core\Render\Element\Textfield
          • class \Drupal\Core\Render\Element\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

Contains \Drupal\Tests\Core\Render\Element\MachineNameTest.

22 #type uses of MachineName

ActionFormBase::form in core/modules/action/src/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 73

Contains \Drupal\Core\Render\Element\MachineName.

Namespace

Drupal\Core\Render\Element

class MachineName extends Textfield {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    $class = get_class($this);
    return array(
      '#input' => TRUE,
      '#default_value' => NULL,
      '#required' => TRUE,
      '#maxlength' => 64,
      '#size' => 60,
      '#autocomplete_route_name' => FALSE,
      '#process' => array(
        array(
          $class,
          'processMachineName',
        ),
        array(
          $class,
          'processAutocomplete',
        ),
        array(
          $class,
          'processAjaxForm',
        ),
      ),
      '#element_validate' => array(
        array(
          $class,
          'validateMachineName',
        ),
      ),
      '#pre_render' => array(
        array(
          $class,
          'preRenderTextfield',
        ),
      ),
      '#theme' => 'input__textfield',
      '#theme_wrappers' => array(
        '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 += array(
      '#title' => t('Machine-readable name'),
      '#description' => t('A unique machine-readable name. Can only contain lowercase letters, numbers, and underscores.'),
      '#machine_name' => array(),
      '#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'] += array(
      'source' => array(
        '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'],
    );

    // By default, machine names are restricted to Latin alphanumeric characters.
    // So, default to LTR directionality.
    if (!isset($element['#attributes'])) {
      $element['#attributes'] = array();
    }
    $element['#attributes'] += array(
      '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 += array(
        '#field_suffix' => '',
      );
      $source['#field_suffix'] = $source['#field_suffix'] . ' <small id="' . $suffix_id . '">&nbsp;</small>';
      $parents = array_merge($element['#machine_name']['source'], array(
        '#field_suffix',
      ));
      NestedArray::setValue($form_state
        ->getCompleteForm(), $parents, $source['#field_suffix']);
    }
    $element['#attached']['library'][] = 'core/drupal.machine-name';
    $element['#attached']['drupalSettings']['machineName']['#' . $source['#id']] = $element['#machine_name'];
    $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 ($element['#default_value'] !== $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

Name	Modifiers	Type	Description	Overrides
DependencySerializationTrait::$_serviceIds	protected	property	An array of service IDs keyed by property name used for serialization.
DependencySerializationTrait::__sleep	public	function		1
DependencySerializationTrait::__wakeup	public	function		2
FormElement::processAutocomplete	public static	function	Adds autocomplete functionality to elements.
FormElement::processPattern	public static	function	#process callback for #pattern form element property.
FormElement::validatePattern	public static	function	#element_validate callback for #pattern form element property.
MachineName::getInfo	public	function	Returns the element properties for this element. Overrides Textfield::getInfo
MachineName::processMachineName	public static	function	Processes a machine-readable name form element.
MachineName::validateMachineName	public static	function	Form element validation handler for machine_name elements.
MachineName::valueCallback	public static	function	Determines how user input is mapped to an element's #value property. Overrides Textfield::valueCallback
PluginBase::$configuration	protected	property	Configuration information passed into the plugin.	2
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	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
PluginBase::getPluginId	public	function	Gets the plugin_id of the plugin instance. Overrides PluginInspectionInterface::getPluginId
PluginBase::__construct	public	function	Constructs a Drupal\Component\Plugin\PluginBase object.	69
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.
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.
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.