Using Currency

There are two main ways to utilize the code from this module.

Price storage does not belong as part of the Currency project. With entity references for config entities supported in Drupal core, any field or entity can use those to reference currencies, and add their own custom price/amount storage.

Basic usage

Configuration

Configure the Currency module under Administration > Configuration > Regional and Language:

• Currency: define or import custom currency types.
• Currency amount formatting: configure amount formatting for different locales.
• Currency exchange: configure how currency exchange rates should be retrieved.

Fields

Currency defines default field types:

1. Entity Reference -> Other (Currency): A field of defined currencies.
2. Exchange rate provider: @todo needs description
3. Amount formatter: @todo needs description

Modules

This is the easiest method, as other modules utilize the Currency module.

• https://www.drupal.org/project/payment
• https://www.drupal.org/project/billing

API Calls

Currency provides three primary API calls.

Form

Adds a currency form item.

  public function buildForm(array $form, FormStateInterface $form_state, $extra = NULL) {
      $form["currency"] = [
        '#type' => 'select',
        '#title' => $this->t('Currency'),
        '#options' => \Drupal::service('currency.form_helper')->getCurrencyOptions(),
        '#required' => TRUE,
      ];
  }

Storage

Uses entity storage to query currency formats.

  /**
   * Duble: \Drupal::service('currency.form_helper')->getCurrencyOptions().
   */
  public static function formOptions() {
    $currency_storage = \Drupal::entityManager()->getStorage('currency');
    $currencies = $currency_storage->loadMultiple();
    $options = [];
    foreach ($currencies as $currency) {
      // Do not show disabled currencies.
      if ($currency->status()) {
        $options[$currency->id()] = t('@currency_title (@currency_code)', [
          '@currency_title' => $currency->label(),
          '@currency_code' => $currency->id(),
        ]);
      }
    }
    natcasesort($options);

    return $options;
  }

Custom-entity field

Adding a currency field as an Entity Reference.

$fields['currency'] = BaseFieldDefinition::create('entity_reference')
  ->setLabel(t('Currency'))
  ->setSetting('target_type', 'currency')
  ->setSetting('handler', 'default')
  ->setDisplayOptions('view', [
    'label' => 'hidden',
    'type' => 'entity_reference_label',
    'settings' => [
      'link' => FALSE,
    ],
  ])
  ->setDisplayOptions('form', [
    'type' => 'options_select',
  ]);