captcha_after.module

<?php

/**
 * @file
 * Main module file for the captcha_after module.
 */

use Drupal\captcha\Entity\CaptchaPoint;
use Drupal\Core\Form\FormStateInterface;

/**
 * Implements hook_module_implements_alter().
 */
function captcha_after_module_implements_alter(&$implementations, $hook) {
  if ($hook == 'form_alter') {
    $group = $implementations['captcha_after'];
    unset($implementations['captcha_after']);
    $implementations['captcha_after'] = $group;
  }
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function captcha_after_form_captcha_point_edit_form_alter(array &$form, FormStateInterface $form_state) {
  // Add captcha delay settings element to the captcha_entity.
  _captcha_after_delay_attempt_element($form, $form_state);
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function captcha_after_form_captcha_point_add_form_alter(array &$form, FormStateInterface $form_state) {
  // Add captcha delay settings element to the captcha_entity.
  _captcha_after_delay_attempt_element($form, $form_state);
}

/**
 * Adds captcha_after settings to captcha_point entity.
 *
 * @param array $form
 *   Form element.
 * @param \Drupal\Core\Form\FormStateInterface $form_state
 *   Form state instance.
 */
function _captcha_after_delay_attempt_element(array &$form, FormStateInterface $form_state) {
  /* @var \Drupal\captcha\Entity\CaptchaPoint $captcha_point */
  $captcha_point = $form_state->getFormObject()->getEntity();

  $form['captcha_after'] = [
    '#type' => 'details',
    '#title' => t('Captcha After Settings'),
    '#description' => t('Captcha after related settings for this captcha point
      entity. Global flooding threshold is evaluated first then Host/IP based
      flooding.'),
    '#open' => FALSE,
  ];

  $form['captcha_after']['captcha_after_global_flooding_threshold'] = [
    '#type' => 'number',
    '#title' => t('CAPTCHA global flooding threshold'),
    '#description' => t('Number of times <strong>ALL</strong> visitors are
      allowed to submit a protected form within an hour before starting to
      protect form with CAPTCHA. This is useful for protecting against flooding
      from multiple IPs. Enter 0 to disable this behaviour.'),
    '#default_value' => $captcha_point->getThirdPartySetting('captcha_after', 'captcha_after_global_flooding_threshold') ?: 0,
  ];

  $form['captcha_after']['captcha_after_flooding_threshold'] = [
    '#type' => 'number',
    '#title' => t('CAPTCHA flooding threshold'),
    '#description' => t('Number of times a visitor (based on hostname/IP) is
      allowed to submit a protected form in an hour before starting to protect
      form with CAPTCHA. This is useful for protecting against repeated (but
      valid) submissions. Enter 0 to disable this behaviour.'),
    '#default_value' => $captcha_point->getThirdPartySetting('captcha_after', 'captcha_after_flooding_threshold') ?: 0,
  ];

  $form['#entity_builders'][] = 'captcha_after_form_captcha_point_entity_builder';
}

/**
 * Entity builder for the captcha point configuration entity.
 */
function captcha_after_form_captcha_point_entity_builder($entity_type, CaptchaPoint $captcha_point, &$form, FormStateInterface $form_state) {
  if ($form_state->getValue('captcha_after_flooding_threshold')) {
    $captcha_point->setThirdPartySetting('captcha_after', 'captcha_after_flooding_threshold', $form_state->getValue('captcha_after_flooding_threshold'));
  }

  if ($form_state->getValue('captcha_after_global_flooding_threshold')) {
    $captcha_point->setThirdPartySetting('captcha_after', 'captcha_after_global_flooding_threshold', $form_state->getValue('captcha_after_global_flooding_threshold'));
  }
}

/**
 * Implements hook_form_alter().
 */
function captcha_after_form_alter(array &$form, FormStateInterface $form_state, $form_id) {
  $captcha = isset($form['captcha'])?: FALSE;

  // If captcha is enabled on the form.
  if ($captcha) {
    /* @var \Drupal\captcha\Entity\CaptchaPoint $captcha_point */
    $captcha_point = \Drupal::entityTypeManager()
      ->getStorage('captcha_point')
      ->load($form_id);

    // Get captcha_after settings.
    $flooding_threshold = $captcha_point->getThirdPartySetting('captcha_after', 'captcha_after_flooding_threshold');
    $global_flooding_threshold = $captcha_point->getThirdPartySetting('captcha_after', 'captcha_after_global_flooding_threshold');

    // If all thresholds are empty or 0, no need to show the captcha.
    if (empty($flooding_threshold) && empty($global_flooding_threshold)) {
      return;
    }

    // Flag to determine hiding the captcha.
    $hide_captcha = FALSE;

    // Set flood variable.
    $flood = $form_state->get('flood') ?: \Drupal::flood();
    if (!$form_state->get('flood')) {
      $form_state->set('flood', $flood);
    }

    // Flood events to register.
    $flood_events = [];

    // If global settings is set on the form.
    if (!empty($global_flooding_threshold)) {
      // Flood event name.
      $flood_event = 'captcha_after_global_flooding_threshold_' . $form['#id'];
      // If flood not exceeds threshold.
      if ($flood->isAllowed($flood_event, $global_flooding_threshold)) {
        // Add to flood event.
        $flood_events[] = $flood_event;
        // Hide the captcha.
        $hide_captcha = TRUE;
      }
    }

    // If Host/IP level threshold is enabled.
    if (!empty($flooding_threshold)) {
      // Flood event name.
      $flood_event = 'captcha_after_flooding_threshold_' . $form['#id'];
      // If flood not exceeds threshold.
      if ($flood->isAllowed($flood_event, $flooding_threshold)) {
        $flood_events[] = $flood_event;
        // Hide the captcha.
        $hide_captcha = TRUE;
      }
      else {
        $hide_captcha = FALSE;
        // If user level flood exceed, no need to then increase global flood.
        $flood_events = [];
      }
    }

    // Hide the captcha.
    if ($hide_captcha) {
      unset($form['captcha']);
    }

    // Register flood event and handlers.
    $form_state->set('flood_events', $flood_events);
    $form['#validate'][] = '_captcha_after_form_validate';
    $form['#submit'][] = '_captcha_after_form_submit';
  }
}

/**
 * Form validation handler to fill the flood.
 */
function _captcha_after_form_validate(&$form, FormStateInterface $form_state) {
  // If there is any error, then register flood.
  if ($form_state->getErrors()) {
    // Available flood events.
    $flood_events = $form_state->get('flood_events');

    // If there is any flood event, register it.
    if (!empty($flood_events)) {
      // The flood object.
      $flood = $form_state->get('flood');
      foreach ($flood_events as $flood_event) {
        $flood->register($flood_event);
      }
    }
  }
}

/**
 * Form submit handler to clear the flood.
 */
function _captcha_after_form_submit(&$form, FormStateInterface $form_state) {
  // Available flood events.
  $flood_events = $form_state->get('flood_events');

  // Clear the flood system.
  if (!empty($flood_events)) {
    // The flood object.
    $flood = $form_state->get('flood');
    foreach ($flood_events as $flood_event) {
      // Do not clear the global threshold flood.
      if (strpos($flood_event, 'captcha_after_global_flooding_threshold_') !== FALSE) {
        continue;
      }
      $flood->clear($flood_event);
    }
  }
}