ICT:D Day problem dd/mm/yyyy

Drupal 11.3 Heritage Date Validation Module

This module implements a modern, **Object-Oriented (OOP)** approach to validate text fields for historical dates (1700s–Present) using the `dd/mm/yyyy` format.

Module Configuration

• Machine Name: heritage_date
• Location: /modules/custom/heritage_date/
• Requirement: Drupal 11.1+ (Uses PHP Attributes for Hooks)

File: heritage_date.info.yml

name: 'Heritage Date Validator'
type: module
description: 'Enforces dd/mm/yyyy format for fields ending in _day.'
package: Custom
core_version_requirement: ^11

File: src/Hook/DateValidationHooks.php

Location: /modules/custom/heritage_date/src/Hook/DateValidationHooks.php

<?php

namespace Drupal\heritage_date\Hook;

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Hook\Attribute\Hook;

/**
 * Validates text fields for dd/mm/yyyy format.
 */
class DateValidationHooks {

  /**
   * Implements hook_form_alter().
   */
  #[Hook('form_alter')]
  public function validateHeritageDate(array &$form, FormStateInterface $form_state, $form_id): void {
    // Add the validation handler to all forms. 
    // The handler will filter by field name suffix.
    $form['#validate'][] = [static::class, 'performRegexCheck'];
  }

  /**
   * Scans form for fields ending in '_day' and validates format.
   */
  public static function performRegexCheck(array &$form, FormStateInterface $form_state): void {
    $values = $form_state->getValues();

    foreach ($values as $field_name => $value) {
      // Dynamic check for our naming convention
      if (str_ends_with($field_name, '_day')) {
        
        $date_string = is_array($value) ? ($value[0]['value'] ?? $value['value'] ?? '') : '';

        if (!empty($date_string)) {
          // Regex for dd/mm/yyyy
          $regex = '/^(0[1-9]|[1-2][0-9]|3)\/(0[1-9]|1[0-2])\/([0-9]{4})$/';
          $label = $form[$field_name]['widget']['#title'] ?? $form[$field_name]['#title'] ?? $field_name;

          if (!preg_match($regex, $date_string)) {
            $form_state->setErrorByName($field_name, t('The @label must be in dd/mm/yyyy format.', ['@label' => $label]));
          } else {
            // Calendar sanity check (Month, Day, Year)
            $parts = explode('/', $date_string);
            if (!checkdate((int)$parts[1], (int)$parts[0], (int)$parts[2])) {
              $form_state->setErrorByName($field_name, t('The @label contains an invalid calendar date.', ['@label' => $label]));
            }
          }
        }
      }
    }
  }
}

Implementation Commands

To enable and register the new hook system:

1. Create the directory structure above.
2. Run: drush en heritage_date
3. Run: drush cr (Cache rebuild is mandatory for Hooks to be discovered).