CardNumber.php in Creditfield Form Element 8

Namespace

Drupal\creditfield\Element

File

src/Element/CardNumber.php

<?php

namespace Drupal\creditfield\Element;

use Drupal\Core\Render\Element\FormElement;
use Drupal\Core\Render\Element;
use Drupal\Core\Form\FormStateInterface;

/**
 * Provides a one-line credit card number field form element.
 *
 * @FormElement("creditfield_cardnumber")
 */
class CardNumber extends FormElement {

  /**
   * {@inheritdoc}
   */
  public function getInfo() {
    $class = get_class($this);
    return [
      '#input' => TRUE,
      '#size' => 60,
      '#maxlength' => 16,
      '#autocomplete_route_name' => FALSE,
      '#element_validate' => [
        [
          $class,
          'validateCardNumber',
        ],
      ],
      '#process' => [
        [
          $class,
          'processCardNumber',
        ],
      ],
      '#pre_render' => [
        [
          $class,
          'preRenderCardNumber',
        ],
      ],
      '#theme' => 'input__textfield',
      '#theme_wrappers' => [
        'form_element',
      ],
    ];
  }

  /**
   * {@inheritdoc}
   */
  public static function processCardNumber(&$element, FormStateInterface $form_state, &$complete_form) {
    return $element;
  }

  /**
   * {@inheritdoc}
   */
  public static function validateCardNumber(&$element, FormStateInterface $form_state, &$complete_form) {
    if (!static::numberIsValid($element['#value'])) {
      $form_state
        ->setError($element, t('Your card appears to be invalid. Please check the numbers and try again.'));
      return;
    }
  }

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

      // Equate $input to the form value to ensure it's marked for
      // validation.
      return str_replace([
        "\r",
        "\n",
      ], '', $input);
    }
  }

  /**
   * Prepares a #type 'creditfield_cardnumber' render element for input.html.twig.
   *
   * @param array $element
   *   An associative array containing the properties of the element.
   *   Properties used: #title, #value, #description, #size, #maxlength,
   *   #placeholder, #required, #attributes.
   *
   * @return array
   *   The $element with prepared variables ready for input.html.twig.
   */
  public static function preRenderCardNumber($element) {
    $element['#attributes']['type'] = 'text';
    Element::setAttributes($element, [
      'id',
      'name',
      'value',
      'size',
      'maxlength',
      'placeholder',
    ]);
    static::setAttributes($element, [
      'form-text',
    ]);
    return $element;
  }

  /**
   * Validate callback for credit card number form fields.
   * Luhn algorithm number checker - (c) 2005-2008 shaman - www.planzero.org
   * @param $value
   * @return bool
   */
  public static function numberIsValid($value) {

    // short circuit here if value is not an integer
    if (!preg_match('/^\\d+$/', $value)) {
      return FALSE;
    }

    // Set the string length and parity
    $cardnumber_length = mb_strlen($value);
    if ($cardnumber_length < 14 || $cardnumber_length > 16) {
      return FALSE;
    }
    $parity = $cardnumber_length % 2;

    // Loop through each digit and do the maths
    $total = 0;
    for ($i = 0; $i < $cardnumber_length; $i++) {
      $digit = $value[$i];

      // Multiply alternate digits by two
      if ($i % 2 == $parity) {
        $digit *= 2;

        // If the sum is two digits, add them together (in effect)
        if ($digit > 9) {
          $digit -= 9;
        }
      }

      // Total up the digits
      $total += $digit;
    }

    // If the total mod 10 equals 0, the number is valid
    return $total % 10 == 0 ? TRUE : FALSE;
  }

}

Classes

Name	Description
CardNumber	Provides a one-line credit card number field form element.