ding_adhl_frontend.module

<?php
/**
 * @REVIEW_COMMENT: Dette modul ville gavne af at blive omskrevet til adhl 3.0.
 * Til denne version af servicen skal man sende en pid og man får en række pid'er retur
 * som kan hentes med object get.
 * Det vil give en simplere kode, og et stort performance boost
 *
 * Der er et par "@todo" kommentarer i koden, bør de ikke fixes/fjernes inden det kommer i
 * core
 */

/**
 * @file
 * Enables the ADHL services to ding2 sites.
 */

/**
 * Implements hook_menu().
 */
function ding_adhl_frontend_menu() {
  $items = array();

  $items['admin/config/ding/adhl'] = array(
    'title' => 'Ding ADHL settings',
    'description' => 'Configure ADHL caching duration and number of elements to fetch.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('ding_adhl_frontend_settings_form'),
    'access arguments' => array('administer adhl recommendations'),
    'file' => 'ding_adhl_frontend.admin.inc',
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function ding_adhl_frontend_permission() {
  return array(
    'administer adhl recommendations' => array(
      'title' => t('Administer ADHL'),
      'description' => t('Administer ADHL recommedation settings'),
    ),
  );
}

/**
 * Implements hook_theme().
 */
function ding_adhl_frontend_theme() {
  return array(
    'ding_adhl_frontend_recommendation_list' => array(
      'variables' => array('type' => 'ul', 'items' => array()),
      'template' => 'templates/ding_adhl_frontend_recommendation_list',
    ),
    'ding_adhl_frontend_recommendation_list_entry' => array(
      'variables' => array('item' => NULL),
      'template' => 'templates/ding_adhl_frontend_recommendation_list_entry',
    ),
  );
}

/**
 * Implements hook_preprocess_HOOK().
 *
 * Default implementation of preprocess function for ding_adhl_frontend_recommendation_list_entry
 * theme function.
 */
function template_preprocess_ding_adhl_frontend_recommendation_list_entry(&$vars) {
  $item = $vars['item'];

  // Build string with the creators.
  $creators = FALSE;
  if (!empty($item->creators)) {
    $creators = implode(", ", $item->creators);
  }
  $vars['creators'] = $creators;

  // Create link and title back to the ting object.
  $uri = entity_uri("ting_object", $item);
  $vars['link'] = array(
    'uri' => url($uri['path']),
    'title' => $item->title . ($creators ? ': ' . $creators : ''),
  );
}

/**
 * Implements hook_flush_caches().
 */
function ding_adhl_frontend_flush_caches() {
  return array('cache_ding_adhl_frontend');
}

/**
 * Implements hook_ctools_plugin_directory().
 *
 * Tells CTools (and thus Panels) where to look for plugin code.
 */
function ding_adhl_frontend_ctools_plugin_directory($module, $plugin) {
  if ($module == 'ctools' || $module == 'panels') {
    return 'plugins/' . $plugin;
  }
}

/**
 * Load TingClientObjects for each recommendation.
 *
 * @param ting $objects
 *  Ting objects (ting entities) that repesent a datawell object. (This may be different stuff array, object, collection ?)
 * @param bool $reset
 *  Reset the cache. Defaults to FALSE.
 * @return ting_entities
 *  An array of recommendations as ting entities.
 */
function ding_adhl_frontend_get_recommended_objects($objects, $reset = FALSE) {
  // Check static cache for recommendations.
  $recommended_objects = &drupal_static(__FUNCTION__);
  if (!isset($recommended_objects) || $reset) {
    // Build cache id to try persistent cache.
    $identifiers = ding_adhl_frontend_extract_identifers($objects);
    $cid = md5(implode('', $identifiers));
    $cache = cache_get($cid, 'cache_ding_adhl_frontend');
    if (!$reset && $cache && $cache->expire > REQUEST_TIME) {
      $recommended_objects = $cache->data;
    }
    else {
      // No cached information was found, so try getting recommendation form the
      // service.
      $number_of_recommendations = variable_get('ding_adhl_frontend_number_to_fetch', 24);
      $local_ids = array();
      foreach ($identifiers as $identifier) {
        // Don't fetch more recommendations that the configured number.
        if (count($local_ids) >= $number_of_recommendations) {
          break;
        }

        // Get the recommendations from the ting client (ADHL service).
        $recommendations = ting_get_object_recommendations($identifier, $number_of_recommendations);
        if (isset($recommendations) && is_array($recommendations)) {
          foreach ($recommendations as $recommendation) {
            $local_ids[$recommendation->localId] = $recommendation;
          }
        }
      }

      // Fetch objects/entities representing the recommendations.
      $recommended_objects = array();
      // Hvorfor hente et andet antal objecter end man skal bruge $number_of_recommendations vs. $number_of_objects
      $number_of_objects = variable_get('ding_adhl_frontend_number_to_display', 10);
      $agency = variable_get('ting_agency', -1);
      foreach (array_keys($local_ids) as $local_id) {
        $ting_object = ding_entity_load(ding_provider_build_entity_id($local_id));

        // Only show objects belonging to our own library.
        if ($ting_object && $ting_object->ownerId == $agency) {
          $recommended_objects[] = $ting_object;

          // Don't get more than we want to display.
          if (count($recommended_objects) >= $number_of_objects) {
            break;
          }
        }
      }

      // Cache the result.
      cache_set($cid, $recommended_objects, 'cache_ding_adhl_frontend', REQUEST_TIME + variable_get('ding_adhl_frontend_cache_duration', 604800));
    }
  }

  return $recommended_objects;
}

/**
 * Helper function that finds ting objects/entites id's based on the type of
 * input given.
 *
 * @todo: There most be a more clean way to get these ids -- cableman.
 *
 * @param mixed $objects
 *   The parameter can be anything from an array to ting object collections.
 */
function ding_adhl_frontend_extract_identifers($objects) {
  if (is_array($objects)) {
    // If passing an array then extract ids from each of the entries.
    $ids = array();
    foreach ($objects as $o) {
      $ids = array_merge($ids, ding_adhl_frontend_extract_identifers($o));
    }
    return array_unique($ids);
  }
  else {
    // If passing a single value then extract ids depending on type.
    switch (get_class($objects)) {
      case 'TingClientObject':
        if (!empty($objects->record['dc:identifier']['dkdcplus:ISBN'])) {
          return $objects->record['dc:identifier']['dkdcplus:ISBN'];
        }
        else {
          return array();
        }
        break;

      case 'TingClientObjectCollection':
        // Get ids from each of the objects in the collection.
        return ding_adhl_frontend_extract_identifers($objects->objects);
        break;

      default:
        // Assume a string or integer has been passed and return it.
        return array($objects);
        break;
    }
  }
}