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 #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

File

core/lib/Drupal/Core/Render/Element/MachineName.php, line 71

Namespace

Drupal\Core\Render\Element

Members