Experimentation hour: add the start of a form to bulk register users

src/Form/UwAddUsersForm.php

+<?php
+
+namespace Drupal\uw_cfg_common\Form;
+
+use Drupal\Core\Form\FormBase;
+use Drupal\Core\Form\FormStateInterface;
+use Drupal\uw_cfg_common\UwPermissions\UwPermissions;
+
+/**
+ * Form class for the content access form.
+ */
+class UwAddUsersForm extends FormBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getFormId() {
+    return 'uw_add_users_form';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function buildForm(array $form, FormStateInterface $form_state) {
+
+    // The list of users this form.
+    $form['users'] = [
+      '#title' => 'WatIAM user ID(s) (maximum 8 characters per ID)',
+      '#description' => 'Enter a single WatIAM user ID, or multiple WatIAM user IDs, one per line.<br>You can use <a href="https://idm.uwaterloo.ca/search/" target="_blank">authenticated WatIAM search</a> if you don\'t know their user ID (will open a new window).',
+      '#type' => 'textarea',
+      '#required' => TRUE,
+    ];
+
+    // The submit button.
+    $form['actions']['#type'] = 'actions';
+    $form['actions']['submit'] = [
+      '#type' => 'submit',
+      '#value' => $this->t('Create new account(s)'),
+      '#button_type' => 'primary',
+    ];
+
+    return $form;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function submitForm(array &$form, FormStateInterface $form_state) {
+
+    // The permissions array that was submitted in the form.
+    $submitted_users = explode(PHP_EOL, $form_state->getValue('users'));
+
+    // Step through each of the submitted users to create if needed/possible,
+    // or show a message if not.
+    foreach ($submitted_users as $row_name => $submitted_user) {
+      $this->messenger()->addStatus($this->t('Normally something would happen here...'));
+    } 
+    // Set the message that the users have been created.
+    $this->messenger()->addStatus($this->t('Finished creating users.'));
+  }
+
+}

uw_cfg_common.links.menu.yml

@@ -450,3 +450,8 @@ uw_site_management.uw_menu_report_csv:
   menu_name: uw-menu-site-management
   route_name: uw_cfg_common.uw_menu_report_csv
   weight: 0
+uw_site_management.uw_add_users:
+  title: 'Add UWaterloo user(s)'
+  menu_name: uw-menu-site-management
+  route_name: uw_add_users.form
+  weight: 0

uw_cfg_common.routing.yml

@@ -48,3 +48,10 @@ uw_cfg_common.uw_menu_report_csv:
     _controller: \Drupal\uw_cfg_common\Controller\UwDownloadCsvController::uwMenuReport
   requirements:
     _permission: 'view UW CSV reports'
+uw_add_users.form:
+  path: '/admin/add-uwaterloo-users'
+  defaults:
+    _title: 'Add UWaterloo User(s)'
+    _form: '\Drupal\uw_cfg_common\Form\UwAddUsersForm'
+  requirements:
+    _permission: 'administer users'