Check For Existing Registration by Email

That's a great point about the plus- and dot-addressing. I wasn't aware of that until now (my organization's email system doesn't support it), but like you said, it's easy to work with. While the entityQuery works for exact email address matches, it won't be able to compare a "clean" (i.e. no ".", no "+", and lowercase) already-registered email address to a "clean" trying-to-register email address, sort of like this:

$query = \Drupal::entityTypeManager()->getStorage('registrant')->getQuery();
$query->condition('eventseries_id', $series_id)
      ->condition('eventinstance_id', $instance_id)
      ->condition(CLEANTHIS('email'), CLEANTHIS('$email_address_to_register'))
      ->execute();

After reading the other issue thread (#3113980: Limit number of registrations allowed), it sounds like limiting registrations to one per email address is still a good idea. I'm thinking we should make it an option when somebody creates/edits an event/series. Do you have suggestions/resources for how to add a new boolean unique_email_address field to that form? The code I've worked up adds the field, but doesn't store the field's value. I've created a new recurring_events_update_xxxx() to alter the schema, but my update didn't go through (sorry, I'm a newbie at _update_):

Failed: Drupal\Core\Database\DatabaseExceptionWrapper: SQLSTATE[42S22]: Column not found: 1054 Unknown column 'eventseries_field_data.event_registration__unique_email_address' in 'field list':

See the attached patch file for all changes I've made against 8.x-1.0-beta2. You'll also see that I've added a $message_type so depending on the registration result, the message can show either as a success, warning, or error.

I have some time in my schedule at the moment, so I'm happy to help in any way.

I've re-rolled this patch to correct some file formatting issues I was having, since I use PowerShell as my terminal:

• Need to use LF instead of CRLF for EOL markers
• Need to use UTF-8 encoding instead of UCS-2 BE BOM
• Need to use spaces instead of 4-space tabs

If anybody else uses PowerShell, here's a script that allows you to create good diff files in one line:

$filename = $args[0]
git diff | Out-File -encoding ASCII $filename
(Get-Content $filename -Raw).Replace("`r`n","`n") | Set-Content $filename -Force

Then, just run the following command:

creatediff [patch_file_name].patch

Thanks @owenbush! I tried applying the patch against a fresh install of 2.0.0-beta1 and 2.0.0-beta2, but neither worked. Which release should I test the patch against?

> git apply --stat recurring_events-existing_registrations
-3183483-7.patch
 .../recurring_events_registration.install          |   98 ++++++++++++++++++++
 .../src/Entity/Registrant.php                      |    1
 .../src/Form/RegistrantForm.php                    |    8 ++
 .../Plugin/Field/FieldType/EventRegistration.php   |   13 ++-
 .../Field/FieldWidget/EventRegistrationWidget.php  |   29 +++++-
 .../src/RegistrationCreationService.php            |   51 ++++++++++
 6 files changed, 193 insertions(+), 7 deletions(-)

> git apply --check recurring_events-existing_registration
s-3183483-7.patch
error: patch failed: modules/recurring_events_registration/recurring_events_registration.install:220
error: modules/recurring_events_registration/recurring_events_registration.install: patch does not apply
error: patch failed: modules/recurring_events_registration/src/Entity/Registrant.php:262
error: modules/recurring_events_registration/src/Entity/Registrant.php: patch does not apply

After applying the versionable registrants patch to a clean install of 2.0.0-beta1, I got the below error. Is there an extra comma on line 109?

Is currently:

$container->has('content_moderation.moderation_information') ? $container->get('content_moderation.moderation_information') : NULL,

Should be:

$container->has('content_moderation.moderation_information') ? $container->get('content_moderation.moderation_information') : NULL

Error:

The website encountered an unexpected error. Please try again later.
ParseError: syntax error, unexpected ')' in Composer\Autoload\includeFile() (line 109 of sites\drupal.dcbfm\modules\recurring_events\modules\recurring_events_registration\src\Form\RegistrantForm.php).

Composer\Autoload\includeFile('C:\WS\repos\drupal/sites/drupal.dcbfm.dd/modules/recurring_events/modules/recurring_events_registration/src\Form\RegistrantForm.php') (Line: 322)
Composer\Autoload\ClassLoader->loadClass('Drupal\recurring_events_registration\Form\RegistrantForm')
spl_autoload_call('Drupal\recurring_events_registration\Form\RegistrantForm')
class_exists('Drupal\recurring_events_registration\Form\RegistrantForm') (Line: 492)
Drupal\Core\Entity\EntityType->hasHandlerClass('form', 'add') (Line: 465)
Drupal\Core\Enti
ty\EntityType->getHandlerClass('form', 'add') (Line: 525)
Drupal\Core\Entity\EntityType->getFormClass('add') (Line: 222)
Drupal\Core\Entity\EntityTypeManager->getFormObject('registrant', 'add') (Line: 82)
Drupal\Core\Entity\HtmlEntityFormController->getFormObject(Object, 'registrant.add.default') (Line: 76)
Drupal\Core\Controller\FormController->getContentResult(Object, Object)
call_user_func_array(Array, Array) (Line: 123)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 573)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 124)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->wrapControllerExecutionInRenderContext(Array, Array) (Line: 97)
Drupal\Core\EventSubscriber\EarlyRenderingControllerWrapperSubscriber->Drupal\Core\EventSubscriber\{closure}() (Line: 151)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 708)
Drupal\Core\DrupalKernel->handle(Object) (Line: 21)

Works like a charm! Thanks for the patch and re-patch. I've now marked this as RTBC.

Hi again! Just one more change to the patch. If somebody is editing their existing registration, we don't have to check for a duplicate email.
So, instead of:

+    if ($unique_email_address && $existing_registration_id) {
+      // If a registration already exists for the email display an error.
+      $form_state->setErrorByName('email', $this->t("You've already registered for this event."));
+    }

It should be

+    if ($entity->isNew() && $unique_email_address && $existing_registration_id) {
+      // If a registration already exists for the email display an error.
+      $form_state->setErrorByName('email', $this->t("You've already registered for this event."));
+    }

That's a great point. We can add a parameter to the hasUserRegisteredByEmail() function that will allow us to optionally exclude a registration ID when checking for duplicate email addresses. Then, when somebody is editing their existing registration, we'll just be sure to send over that existing registration ID as the ID to not be checked against.

RegistrationCreationService.php hasUserRegisteredByEmail:

  public function hasUserRegisteredByEmail($email, $registration_to_exclude = null) {
    // Look through this series' registrations.
    $existing_registration_id = FALSE;
    $current_series_registrations = $this->retrieveAllSeriesRegisteredParties();
    foreach ($current_series_registrations as $registration_id => $registration_record) {
      // Compare the event instance ID and email address.
      if (((!isset($registration_to_exclude)) || ($registration_id != $registration_to_exclude))
        && ($this->eventInstance->id() == $registration_record->get('eventinstance_id')->target_id)
        && ($this->cleanEmailAddress($email) == $this->cleanEmailAddress($registration_record->get('email')->value))) {
        // Remember the existing registration ID and stop looking.
        $existing_registration_id = $registration_id;
        break;
      }
    }
    return $existing_registration_id;
  }

RegistrantForm.php validateForm():

    $unique_email_address = $this->creationService->registrationUniqueEmailAddress();
    $email_address = $form_state->getValue('email');
    $registration_to_exclude = ($entity->isNew() ? null : $entity->id());
    $existing_registration_id = $this->creationService->hasUserRegisteredByEmail($email_address[0]['value'], $registration_to_exclude);
    if ($unique_email_address && $existing_registration_id) {
      // If a registration already exists for the email display an error.
      $form_state->setErrorByName('email', $this->t("You've already registered for this event."));
    }

Thanks for putting out that patch! It didn't apply cleanly for me, for either 2.0.0-beta1 or 2.0.0-beta2. I was using the beta1 and beta2 code pulled fresh from the project page.

2.0.0-beta1:

PS C:\WS\repos\2.0.0-beta1\recurring_events> git apply --check recurring_events-existing_registrations-3183483-20.patch
error: patch failed: modules/recurring_events_registration/recurring_events_registration.install:220
error: modules/recurring_events_registration/recurring_events_registration.install: patch does not apply
error: patch failed: modules/recurring_events_registration/src/Entity/Registrant.php:262
error: modules/recurring_events_registration/src/Entity/Registrant.php: patch does not apply
error: patch failed: modules/recurring_events_registration/src/Plugin/Field/FieldWidget/EventRegistrationWidget.php:277
error: modules/recurring_events_registration/src/Plugin/Field/FieldWidget/EventRegistrationWidget.php: patch does not apply

2.0.0-beta2:

PS C:\WS\repos\2.0.0-beta2\recurring_events> git apply --check recurring_events-existing_registrations-3183483-20.patch
error: patch failed: modules/recurring_events_registration/recurring_events_registration.install:220
error: modules/recurring_events_registration/recurring_events_registration.install: patch does not apply
error: patch failed: modules/recurring_events_registration/src/Entity/Registrant.php:262
error: modules/recurring_events_registration/src/Entity/Registrant.php: patch does not apply