function form_validate_machine_name in Drupal 7

Form element validation handler for machine_name elements.

Note that #maxlength is validated by _form_validate() already.

Related topics

1 string reference to 'form_validate_machine_name'

system_element_info in modules/system/system.module

Implements hook_element_info().

File

includes/form.inc, line 3702

Functions for form and batch generation and processing.

Code

function form_validate_machine_name(&$element, &$form_state) {

  // Verify that the machine name not only consists of replacement tokens.
  if (preg_match('@^' . $element['#machine_name']['replace'] . '+$@', $element['#value'])) {
    form_error($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 ($element['#machine_name']['replace'] == '-') {
        form_error($element, t('The machine-readable name must contain only lowercase letters, numbers, and hyphens.'));
      }
      else {
        form_error($element, t('The machine-readable name must contain only lowercase letters, numbers, and underscores.'));
      }
    }
    else {
      form_error($element, $element['#machine_name']['error']);
    }
  }

  // Verify that the machine name is unique.
  if ($element['#default_value'] !== $element['#value']) {
    $function = $element['#machine_name']['exists'];
    if ($function($element['#value'], $element, $form_state)) {
      form_error($element, t('The machine-readable name is already in use. It must be unique.'));
    }
  }
}