block_refresh.module

<?php
/**
 * @file
 * Allows blocks to automatically refresh their content.
 */

define('BLOCK_REFRESH_DEFAULT_AUTOMATIC', FALSE); // autorefresh disabled by default
define('BLOCK_REFRESH_DEFAULT_MANUAL', FALSE); // manual refresh disabled by default
define('BLOCK_REFRESH_DEFAULT_INIT', FALSE); // inital refresh disabled by default
define('BLOCK_REFRESH_DEFAULT_BYPASS_PAGE_CACHE', FALSE); // page cache bypass disabled by default
define('BLOCK_REFRESH_DEFAULT_BYPASS_EXTERNAL_CACHE', ''); // external cache bypass disabled by default
define('BLOCK_REFRESH_DEFAULT_AUTOMATIC_TIMER', 120);  // default refreshes every two minutes, if enabled

/**
 * Implements hook_block_view_alter().
 *
 * Adds the jquery to refresh blocks automatically.
 */
function block_refresh_block_view_alter(&$data, $block) {
  if (array_key_exists('block_refresh', $block->settings) && !empty($block->settings['block_refresh'])) {
    // Add extra settings.
    $element = backdrop_clean_css_identifier('block-' . $block->module . '-' . $block->delta);
    $block->settings['block_refresh']['element'] = $element;
    $block->settings['block_refresh']['module'] = $block->module;
    $block->settings['block_refresh']['delta'] = $block->delta;
    $block->settings['block_refresh']['uuid'] = $block->uuid;

    // Add assets to the page.
    $path = backdrop_get_path('module', 'block_refresh');
    backdrop_add_js($path . '/js/block_refresh.js', array('scope' => 'footer'));
    backdrop_add_css($path . '/css/block_refresh.css');
    backdrop_add_js(array(
      'block_refresh' => array(
        'settings' => $block->settings['block_refresh'],
        'args' => arg(),
        'query' => block_refresh_get_query_as_string(),
        'cleanUrl' => (bool) config_get('system.core', 'clean_url'),
      )
    ), 'setting');

    /* @todo Find out why #attached does not work here.
    $data['#attached'] = array(
      'css' => array($path . '/css/block_refresh.css'),
      'js' => array($path . '/js/block_refresh.js' => array('scope' => 'footer')),
    );
    $data['#attached']['js'][] = array(
      'data' => array('block_refresh' => $block_refresh_settings),
      'type' => 'setting',
    );
    */
  }
}


/**
 * Implements hook_form_FORM_ID_alter().
 *
 * Adds a 'Block Refresh' settings fieldset to the block admin form.
 */
function block_refresh_form_layout_block_configure_form_alter(&$form, $form_state) {
  $form['block_refresh'] = array(
    '#type' => 'fieldset',
    '#title' => t('Refresh settings'),
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
    '#tree' => TRUE,
  );
  if (($form_state['block']->module == 'system' && $form_state['block']->delta == 'main')) {
    $form['block_refresh']['#collapsed'] = FALSE;
    $form['block_refresh']['no'] = array(
      '#type' => 'markup',
      '#markup' => t('The main page content block cannot be refreshed.'),
    );
  }
  else {
    block_refresh_settings_form_elements($form, $form_state);
    // Call our submit handler before layout's.
    array_unshift($form['#submit'], 'block_refresh_submit');
  }
}

/**
 * Helper function: Generates the form elements for block refresh settings.
 *
 * @param $form
 *   The block settings form.
 */
function block_refresh_settings_form_elements(&$form, $form_state) {
  $settings = array();
  if (isset($form_state['block']->settings['block_refresh'])) {
    $settings = $form_state['block']->settings['block_refresh'];
    $form['block_refresh']['#collapsed'] = FALSE;
  }

  $timer_setting = isset($settings['timer']) ? $settings['timer'] : BLOCK_REFRESH_DEFAULT_AUTOMATIC_TIMER;

  $form['block_refresh']['auto'] = array(
    '#type' => 'checkbox',
    '#title' => t('Refresh automatically'),
    '#description' => t('When checked, the content of this block will refresh automatically every @timer seconds (defined below).', array('@timer' => $timer_setting)),
    '#default_value' => isset($settings['auto']) ? $settings['auto'] : BLOCK_REFRESH_DEFAULT_AUTOMATIC,
  );
  $form['block_refresh']['timer'] = array(
    '#type' => 'number',
    '#title' => t('Block refresh interval'),
    '#field_suffix' => t('seconds'),
    '#default_value' => $timer_setting,
    '#states' => array(
      'visible' => array(
        ':input[name="block_refresh[auto]"]' => array('checked' => TRUE),
      ),
    ),
  );
  $form['block_refresh']['init'] = array(
    '#type' => 'checkbox',
    '#title' => t('Refresh on page load'),
    '#description' => t('When checked, the content of this block will be refreshed every time the page loads.'),
    '#default_value' => isset($settings['init']) ? $settings['init'] : BLOCK_REFRESH_DEFAULT_INIT,
  );
  $form['block_refresh']['manual'] = array(
    '#type' => 'checkbox',
    '#title' => t('Refresh manually'),
    '#description' => t('When checked, the content of this block may be refreshed manually by clicking a button in the block\'s header.'),
    '#default_value' => isset($settings['manual']) ? $settings['manual'] : BLOCK_REFRESH_DEFAULT_MANUAL,
  );

  $form['block_refresh']['cache'] = array(
    '#type' => 'fieldset',
    '#title' => t('Cache settings'),
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
  );
  $form['block_refresh']['cache']['bypass_page_cache'] = array(
    '#type' => 'checkbox',
    '#title' => t('Bypass page cache'),
    '#description' => t('When checked, the refreshed content of this block will bypass the page cache. If stale content is being served to you due to caching, try checking this box. <em>Warning! this can have a performance impact</em>.'),
    '#default_value' => isset($settings['bypass_page_cache']) ? $settings['bypass_page_cache'] : BLOCK_REFRESH_DEFAULT_BYPASS_PAGE_CACHE,
  );
  $form['block_refresh']['cache']['bypass_external_cache'] = array(
    '#type' => 'number',
    '#title' => t('External cache max age'),
    '#field_suffix' => t('seconds'),
    '#description' => t('If you wish to override the max age of refreshed data served from an external cache (eg Varnish), enter a value here. Leave blank to use your sitewide default value.'),
    '#default_value' => isset($settings['bypass_external_cache']) ? $settings['bypass_external_cache'] : BLOCK_REFRESH_DEFAULT_BYPASS_EXTERNAL_CACHE,
  );
}

/**
 * Submit handler for for block_refresh_menu().
 *
 * Handles form submissions on the block configuration page.
 */
function block_refresh_submit($form, &$form_state) {
  $settings = array();
  if (isset($form_state['block']->settings['block_refresh'])) {
    $settings = $form_state['block']->settings['block_refresh'];
  }

  if (($form_state['values']['block_refresh']['auto'] == 0) &&
      ($form_state['values']['block_refresh']['manual'] == 0) &&
      ($form_state['values']['block_refresh']['init'] == 0)) {
    // Remove all block refresh settings if refresh is disabled.
    $form_state['block']->settings['block_refresh'] = array();
  }
  else {
    if (is_null($settings)) {
      $settings = array();
    }
    foreach ($form_state['values']['block_refresh'] as $key => $value) {
      // Flatten all refresh settings into an one-dimensional array.
      if (is_array($value)) {
        foreach ($value as $inner_key => $inner_value) {
          $settings[$inner_key] = $inner_value;
        }
        unset($form_state['values']['block_refresh'][$key]);
        unset($settings[$key]);
      }
      else {
        $settings[$key] = $value;
      }
    }

    $form_state['block']->settings['block_refresh'] = $settings;
  }
}

/**
 * Implements hook_menu().
 */
function block_refresh_menu() {
  $items = array();
  $items['block_refresh'] = array(
    'title' => 'Block refresh block content',
    'page callback' => 'block_refresh_block_content',
    'page arguments' => array(1, 2, 3),
    'access arguments' => array('access content'),
    'type' => MENU_CALLBACK,
  );
  return $items;
}

/**
 * Page callback for /block_refresh/[module]/[delta]/[uuid].
 *
 * Displays the block content without any other page information.
 *
 * @param string $module
 *  Module that provided the block.
 *
 * @param string $delta
 *  Identifies which block provided by a given module.
 *
 * @param string $uuid
 *  Identifies which instance of the block is to be refreshed.
 *
 * @return string
 *  Rendered content of the block, or 404 if there was a problem.
 */
function block_refresh_block_content($module = NULL, $delta = NULL, $uuid = NULL) {
  // 404 if there is a request directly to /block_refresh or UUID is not set.
  if (!isset($module) || !isset($delta) || !isset($uuid)) {
    backdrop_not_found();
  }

  $menu_router_item = menu_get_item();
  $layout = layout_get_layout_by_path(NULL, $menu_router_item);

  if (isset($layout->content[$uuid])) {
    $settings = $layout->content[$uuid]->settings['block_refresh'];

    // If automatic refresh AND manual refresh are both disabled...
    if (empty($settings) || (!$settings['auto'] && !$settings['manual'] && !$settings['init'])) {
      backdrop_not_found();
    }

    // Bypass page cache if set.
    if (isset($settings['bypass_page_cache']) && $settings['bypass_page_cache'] == 1) {
      $GLOBALS['conf']['cache'] = FALSE;
    }

    // Override external cache max age if set.
    if (isset($settings['bypass_external_cache']) && $settings['bypass_external_cache'] != '') {
      backdrop_add_http_header('Cache-Control', 'public, max-age=' . intval($settings['bypass_external_cache']));
    }

    $output = $layout->content[$uuid]->getContent();
    print $output;
  }
  else {
    $message = 'A block with UUID :uuid was not found in the active layout.';
    $replacements = array(':uuid' => $uuid);
    watchdog('block_refresh', $message, $replacements, WATCHDOG_WARNING);
  }
}

/**
 * Private function: Gets all $_GET values (except q and render).
 *
 * @return string
 *  A query string representing the arguments.
 */
function block_refresh_get_query_as_string() {
  $variables = $_GET;
  if (!empty($variables['q'])) {
    unset($variables['q']);
  }
  if (!empty($variables['render'])) {
    unset($variables['render']);
  }
  if (count($variables) > 0) {
    $querystring = '?' . http_build_query($variables);
    return $querystring;
  }
  else {
    return '';
  }
}