readonlymode.module in Read only mode 8

Read Only Mode provides an alternative to the built in 'Maintenance Mode' in Drupal. Instead of displaying a static text file to users while the site is in maintenance mode, Read Only Mode will allow access (reading) of existing content while preventing changing or adding content (posting / submitting. forms / etc).

This allows the site to remain functional while maintenance is performed. This module also provides messaging to users and administrators to indicate that the site is in maintenance mode.

File

readonlymode.module

<?php

/**
 * @file
 * Read Only Mode provides an alternative to the built in 'Maintenance Mode' in
 * Drupal. Instead of displaying a static text file to users while the site is
 * in maintenance mode, Read Only Mode will allow access (reading) of existing
 * content while preventing changing or adding content (posting / submitting.
 * forms / etc).
 *
 * This allows the site to remain functional while maintenance is performed.
 * This module also provides messaging to users and administrators to indicate
 * that the site is in maintenance mode.
 */
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Render\Element;
use Symfony\Component\HttpFoundation\RedirectResponse;

/**
 * Implements hook_form_FORM_ID_alter().
 */
function readonlymode_form_system_site_maintenance_mode_alter(&$form, FormStateInterface $form_state) {
  $settings = \Drupal::config('readonlymode.settings');
  $form['read_only'] = [
    '#title' => t('Read Only Mode'),
    '#type' => 'details',
    '#weight' => 1,
    '#open' => TRUE,
  ];
  $form['read_only']['enable_readonly'] = [
    '#type' => 'checkbox',
    '#title' => t('Enable "Read Only" mode'),
    '#description' => t('When set to "Read Only", all content moderation (add/edit) will be impossible.'),
    '#weight' => 0,
    '#default_value' => $settings
      ->get('enabled'),
  ];

  // Message configuration is in a collapsed fieldset
  // so that it doesn't clutter the display.
  $form['read_only']['settings'] = [
    '#title' => t('Messages and redirects'),
    '#type' => 'details',
    '#description' => t('Configure the redirect URL and messages to display to users while the site is in Read Only Mode.'),
  ];
  $form['read_only']['settings']['default_message'] = [
    '#type' => 'textarea',
    '#title' => t('Read Only Mode warning'),
    '#description' => t('This warning will be displayed when viewing a page that has a blocked form while in Read Only Mode.'),
    '#default_value' => $settings
      ->get('messages.default'),
    '#rows' => 3,
    '#required' => TRUE,
  ];
  $form['read_only']['settings']['not_saved_message'] = [
    '#type' => 'textarea',
    '#title' => t('Form submission error'),
    '#description' => t('This error will be displayed when a blocked form is submitted while in Read Only Mode. This scenario occurs when a user starts filling out a form during normal site operation and then attempts to submit the form after Read Only Mode has been enabled.'),
    '#default_value' => $settings
      ->get('messages.not_saved'),
    '#rows' => 3,
    '#required' => TRUE,
  ];
  $form['read_only']['settings']['url'] = [
    '#type' => 'textfield',
    '#title' => t('Redirect path'),
    '#description' => t('When given, Drupal will redirect the user to this URL when a user tries to add/edit content instead of displaying the message above.'),
    '#default_value' => $settings
      ->get('url'),
  ];

  // Allowed forms configuration is in a collapsed fieldset
  // so that it doesn't clutter the display.
  $form['read_only']['forms'] = [
    '#title' => t('Allowed forms'),
    '#type' => 'details',
    '#description' => t('Configure which forms will be excluded from restriction when in read-only mode.'),
  ];
  $form['read_only']['forms']['additional_edit'] = [
    '#type' => 'textarea',
    '#title' => t('Forms that can be submitted'),
    '#description' => t("These forms are not restricted when in read only mode. Enter one form id per line. You may use the wildcard character '*' to use loose matches. For example: webform* will match all webforms. Note that the following forms will always be allowed: %allowed_forms.", [
      '%allowed_forms' => empty($settings
        ->get('forms.default.edit')) ? '' : implode(', ', $settings
        ->get('forms.default.edit')),
    ]),
    '#default_value' => $settings
      ->get('forms.additional.edit'),
  ];
  $form['read_only']['forms']['additional_view'] = [
    '#type' => 'textarea',
    '#title' => t('Forms that can be viewed'),
    '#description' => t("These forms are allowed to be viewed but will not accept form submissions. Enter one form id per line. You may use the wildcard character '*' to use loose matches. For example: webform* will match all webforms. Note that the following forms will always be allowed: %allowed_forms.", [
      '%allowed_forms' => empty($settings
        ->get('forms.default.view')) ? '' : implode(', ', $settings
        ->get('forms.default.view')),
    ]),
    '#default_value' => $settings
      ->get('forms.additional.view'),
  ];
  $form['#validate'][] = 'readonlymode_settings_form_validate';
  $form['#submit'][] = 'readonlymode_settings_form_submit';
}

/**
 * Settings form validate handler.
 *
 * See readonlymode_form_system_site_maintenance_mode_alter().
 */
function readonlymode_settings_form_validate(array &$form, FormStateInterface $form_state) {
  $values = $form_state
    ->getValues();
  if ($path = $values['url']) {
    $path_validator = \Drupal::pathValidator();
    if (!$path_validator
      ->isValid($form_state
      ->getValue('url'))) {
      $form_state
        ->setErrorByName('url', t('The path %link_path is either invalid or you do not have access to it.', [
        '%link_path' => $path,
      ]));
    }
  }
}

/**
 * Settings form submission handler.
 *
 * See readonlymode_form_system_site_maintenance_mode_alter().
 */
function readonlymode_settings_form_submit(array &$form, FormStateInterface $form_state) {
  $values = $form_state
    ->getUserInput();
  \Drupal::configFactory()
    ->getEditable('readonlymode.settings')
    ->set('enabled', $values['enable_readonly'])
    ->set('url', $values['url'])
    ->set('messages.default', $values['default_message'])
    ->set('messages.not_saved', $values['not_saved_message'])
    ->set('forms.additional.edit', $values['additional_edit'])
    ->set('forms.additional.view', $values['additional_view'])
    ->save();
}

/**
 * Implements hook_form_alter().
 *
 * Permit posting of content.
 */
function readonlymode_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $settings = \Drupal::config('readonlymode.settings');
  if (!_readonlymode_form_check($form, $form_id, FALSE)) {

    // If a redirect URL is set, then we redirect to it.
    if ($url = $settings
      ->get('url')) {
      return new RedirectResponse($url);
    }
    else {

      // Remove FAPI #after_build handlers.
      $form['#after_build'] = [];

      // Remove all elements of the form.
      foreach (Element::children($form) as $key) {
        if (!in_array($key, [
          'form_id',
          'form_token',
          'form_build_id',
        ])) {
          unset($form[$key]);
        }
      }
      $form['readonly_notice'] = [
        '#markup' => \Drupal::token()
          ->replace($settings
          ->get('messages.default')),
        '#prefix' => '<div class="messages warning">',
        '#suffix' => '</div>',
      ];
    }
  }
  if (\Drupal::currentUser()
    ->hasPermission('readonlymode access forms') && $settings
    ->get('enabled')) {
    \Drupal::messenger()
      ->addMessage(t('The site is currently set to Read Only, content moderation is disabled for all users without the "Access all forms while in Read Only Mode" permission.'), 'warning', FALSE);
  }
  $form['#validate'][] = 'readonlymode_check_form_validate';
}

/**
 * Validation handler for all form submissions.
 *
 * Checks whether the form submission is
 * occurring while Read Only Mode is enabled.
 */
function readonlymode_check_form_validate(array &$form, FormStateInterface $form_state) {

  // Check for Read Only Mode, whether we are allowed this form,.
  if (!_readonlymode_form_check($form, $form['form_id']['#value'], TRUE)) {
    $form_state
      ->setErrorByName('submit', \Drupal::token()
      ->replace(\Drupal::config('readonlymode.settings')
      ->get('messages.not_saved')));
  }
}

/**
 * Helper function to check form submissions.
 *
 * Internal handler to check whether this form is to be restricted.
 *
 * @param array $form
 *   The full form.
 * @param string $form_id
 *   The form ID.
 * @param bool $submitted
 *   Defaults to TRUE.
 *
 * @return bool
 *   TRUE when matched, FALSE otherwise.
 */
function _readonlymode_form_check(array &$form, $form_id, $submitted = TRUE) {
  $settings = \Drupal::config('readonlymode.settings');

  // If not in Read Only Mode, allow the form.
  if (!$settings
    ->get('enabled')) {
    return TRUE;
  }

  // Admins can access all forms.
  if (\Drupal::currentUser()
    ->hasPermission('readonlymode access forms')) {
    return TRUE;
  }

  // Is the form in the list of default forms? Then allow access.
  if (in_array($form_id, $settings
    ->get('forms.default.edit'))) {
    return TRUE;
  }

  // Is the form in the list of read-only forms? Then allow access.
  if (!$submitted && in_array($form_id, $settings
    ->get('forms.default.view'))) {
    return TRUE;
  }

  // Check if the form is in the custom list of allowed forms. If so, allow.
  if (_readonlymode_form_list_check($form_id, $settings
    ->get('forms.additional.edit'))) {
    return TRUE;
  }

  // Check if the form is in the custom list of allowed read-only forms.
  if (!$submitted && _readonlymode_form_list_check($form_id, $settings
    ->get('forms.additional.view'))) {
    return TRUE;
  }
  return FALSE;
}

/**
 * Check for form_id in a given list.
 *
 * @param array $list
 *   A string of form id's separated by newlines.
 *
 * @return bool
 *   TRUE when matched, FALSE otherwise.
 */
function _readonlymode_form_list_check($form_id, array $list) {
  $l = preg_split('/(\\r\\n|\\n|\\r)/', $list);
  foreach ($l as $word) {

    // Skip empty words.
    if (empty($word)) {
      continue;
    }
    $word = str_replace('*', '.*', $word);
    if (preg_match('/^' . $word . '$/', $form_id) === 1) {
      return TRUE;
    }
  }
  return FALSE;
}

Functions

Name	Description
readonlymode_check_form_validate	Validation handler for all form submissions.
readonlymode_form_alter	Implements hook_form_alter().
readonlymode_form_system_site_maintenance_mode_alter	Implements hook_form_FORM_ID_alter().
readonlymode_settings_form_submit	Settings form submission handler.
readonlymode_settings_form_validate	Settings form validate handler.
_readonlymode_form_check	Helper function to check form submissions.
_readonlymode_form_list_check	Check for form_id in a given list.