islandora_blocks.module

<?php

/**
 * @file
 * Hooks, callbacks, and helper functions for the Islandora Blocks module.
 */

/* Hooks. */

/**
 * Implements hook_theme().
 */
function islandora_blocks_theme($existing, $type, $theme, $path) {
  return array(
    'islandora_blocks_datastreams' => array(
      'template' => 'templates/islandora-blocks-datastreams',
      'variables' => array('datastreams' => array()),
    ),
  );
}

/**
 * Implements hook_block_info().
 */
function islandora_blocks_block_info() {

  $blocks['metadata'] = array(
    'info' => t('Object Metadata'),
  );

  $blocks['collections'] = array(
    'info' => t('Object Collections'),
  );

  $blocks['datastreams'] = array(
    'info' => t('Object Datastreams'),
  );

  if (module_exists('csl')) {
    $blocks['citation'] = array(
      'info' => t('Object Citation'),
    );
  }

  return $blocks;
}

/**
 * Implements hook_block_view().
 */
function islandora_blocks_block_view($delta = '') {
  // If there is no object there are no blocks.
  $object = menu_get_object('islandora_object', 2);
  if (!$object) {
    return FALSE;
  }

  // We should be on the "view" callback.
  $menu_item = menu_get_item();
  if ($menu_item['path'] != 'islandora/object/%/view' && $menu_item['path'] != 'islandora/object/%') {
    return FALSE;
  }

  $block = array();
  switch ($delta) {
    case 'metadata':
      $form = drupal_get_form('islandora_blocks_metadata_form', $object);

      $block['subject'] = t('Metadata');
      $block['content'] = drupal_render($form);
      break;

    case 'collections':
      $block['subject'] = t('Parent Collections');
      $block['content'] = array(
        '#theme' => 'item_list',
        '#type' => 'ul',
        '#items' => array(),
      );
      $parents = $object->relationships->get(NULL, 'isMemberOfCollection');
      if (count($parents) == 0) {
        return FALSE;
      }
      $return = FALSE;
      foreach ($parents as $parent) {
        try {
          $obj = islandora_object_load($parent['object']['value']);
          if ($obj) {
            $return = TRUE;
            $block['content']['#items'][] = l($obj->label, 'islandora/object/' . $obj->id);
          }
        }
        catch (Exception $e) {
          // No-op.
        }
      }

      // Couldn't load any parents, return nothing.
      if (!$return) {
        return FALSE;
      }
      break;

    case 'datastreams':
      foreach ($object as $ds) {
        try {
          module_load_include('inc', 'islandora', 'includes/datastream');
          $pid = $object->id;
          $id = $ds->id;
          $label = $ds->label;
          $download_path = islandora_datastream_get_url($ds, 'download');
          $datastreams[$id]['id'] = $id;
          $datastreams[$id]['label'] = $label;
          $datastreams[$id]['label_link'] = islandora_datastream_access(ISLANDORA_VIEW_OBJECTS, $ds) ?
            l($label, $download_path) :
            $label;
          $datastreams[$id]['download_url'] = $download_path;
          $datastreams[$id]['mimetype'] = $ds->mimetype;
          $datastreams[$id]['size'] = islandora_datastream_get_human_readable_size($ds);
          $datastreams[$id]['created_date'] = $ds->createdDate->format("Y-m-d");
          $datastreams[$id]['class'] = drupal_strtolower(preg_replace('/[^A-Za-z0-9]/', '-', $id));
          $block['subject'] = t('Datastreams');
          $block['content'] = array(
            '#theme' => 'islandora_blocks_datastreams',
            '#datastreams' => $datastreams,
          );
        }
        catch (RepositoryException $e) {
          // No-op.
        }
      }
      break;

    case 'citation':
      // To provide a citation we need a MODS record.
      if (!isset($object['MODS'])) {
        return FALSE;
      }
      $block['subject'] = t('Citation');
      $block['content'] = citeproc_bibliography_from_mods(citeproc_style(variable_get('islandora_blocks_citation_style')), $object['MODS']->content);
      break;
  }

  return $block;
}

/**
 * Implements hook_block_configure().
 */
function islandora_blocks_block_configure($delta = '') {
  $form = array();

  if ($delta == 'citation') {
    module_load_include('inc', 'csl', 'includes/csl');
    $form['islandora_blocks_citation_style'] = array(
      '#type' => 'select',
      '#title' => t('Citation Style to Use'),
      '#default_value' => variable_get('islandora_blocks_citation_style'),
      '#options' => drupal_map_assoc(CSL::GetNames()),
      '#element_validate' => array('islandora_blocks_configure_validate'),
    );
  }
  elseif ($delta === 'metadata') {
    // Allow the block administrator to choose which metadata sets are displayed
    // in the metadata block.
    $form['islandora_blocks_metadata_sets_display'] = array(
      '#type' => 'checkboxes',
      '#title' => t('Metadata sets to display'),
      '#description' => t('Choose the sets of metadata to display. Only one dataset is displayed at a time; but if you choose more than one, a control will be shown to let the viewer toggle which set of metadata is currently shown.'),
      '#options' => _islandora_blocks_available_metadata_sets(),
      '#default_value' => variable_get('islandora_blocks_metadata_sets_display', array('dc_metadata' => 'dc_metadata')),
    );
  }

  return $form;
}

/**
 * Implements hook_block_save().
 */
function islandora_blocks_block_save($delta = '', $edit = array()) {
  if ($delta === 'metadata') {
    // Allow the block administrator to choose which metadata sets are displayed
    // in the metadata block.
    variable_set('islandora_blocks_metadata_sets_display', $edit['islandora_blocks_metadata_sets_display']);
  }
}

/* Form API callbacks. */

/**
 * Element validation callback: validate citation styles.
 *
 * @param array $form
 *   A form array.
 * @param array $form_state
 *   A form state array.
 *
 * @see islandora_blocks_block_configure()
 */
function islandora_blocks_configure_validate($form, &$form_state) {
  variable_set('islandora_blocks_citation_style', $form_state['values']['islandora_blocks_citation_style']);
}

/**
 * Form callback: Form constructor for a display of metadata.
 *
 * @param array $form
 *   The form object.
 * @param array &$form_state
 *   The form state object. Must contain the Fedora object that we want to
 *   display the metadata form as the first item in the array at
 *   $form_state['build_info']['args'].
 *
 * @return array
 *   A form array for metadata.
 *
 * @ingroup forms
 */
function islandora_blocks_metadata_form($form, &$form_state) {
  $available_metadata_sets = _islandora_blocks_available_metadata_sets();
  $configured_metadata_sets = variable_get('islandora_blocks_metadata_sets_display', array('dc_metadata' => 'dc_metadata'));
  $to_display = array_intersect_key($available_metadata_sets, $configured_metadata_sets);

  // The Fedora object should be the first build argument.
  $object = reset($form_state['build_info']['args']);

  // If we have determined that the dependencies to display Solr metadata are
  // available, and the block administrator wants to display Solr metadata in
  // this block, display the container.
  if (array_key_exists('solr_metadata', $to_display)) {
    // Find the fields we should query and display.
    module_load_include('inc', 'islandora_solr_metadata', 'includes/db');
    $associations = islandora_solr_metadata_get_associations_by_cmodels($object->models);

    // Render the object's Solr metadata.
    $form['solr_metadata'] = array(
      '#type' => 'container',
      'metadata' => array(
        '#theme' => 'islandora_solr_metadata_display',
        '#islandora_object' => $object,
        '#print' => TRUE,
        '#associations' => $associations,
      ),
      '#states' => array(
        'visible' => array(
          ':input[name="metadata_toggle"]' => array('value' => 'solr_metadata'),
        ),
      ),
    );
  }

  // If we have determined that the dependencies to display DC metadata are
  // available, and the block administrator wants to display DC metadata in this
  // block, display the container.
  if (array_key_exists('dc_metadata', $to_display)) {
    // Render the object's DC metadata.
    $form['dc_metadata'] = array(
      '#type' => 'container',
      'metadata' => array(
        '#theme' => 'islandora_dublin_core_display',
        '#islandora_object' => $object,
        '#print' => TRUE,
      ),
      '#states' => array(
        'visible' => array(
          ':input[name="metadata_toggle"]' => array('value' => 'dc_metadata'),
        ),
      ),
    );
  }

  // Add a form control to toggle the visible metadata.
  if (count($to_display) > 1) {
    $metadata_toggle_default = (array_key_exists('solr_metadata', $available_metadata_sets)) ? 'solr_metadata' : 'dc_metadata';
    $form['metadata_toggle'] = array(
      '#type' => 'radios',
      '#title' => t('Metadata to display'),
      '#options' => $to_display,
      '#default_value' => $metadata_toggle_default,
      '#weight' => -1,
    );
  }

  return $form;
}

/* Helper functions. */

/**
 * Return a list of available metadata sets.
 *
 * @return array
 *   An associative array of zero or more metadata sets:
 *   - solr_metadata: Indexed (Solr) Metadata
 *   - dc_metadata: Basic (Dublin Core) Metadata
 */
function _islandora_blocks_available_metadata_sets() {
  // Cache metadata sets per request.
  $available_metadata_sets = &drupal_static(__FUNCTION__);
  if (!isset($available_metadata_sets)) {
    $available_metadata_sets = array();

    // If the Islandora Solr Metadata module is installed, we can display
    // Indexed Solr metadata.
    if (module_exists('islandora_solr_metadata')) {
      $available_metadata_sets['solr_metadata'] = t('Indexed (Solr) Metadata');
    }

    // If the Islandora module is available, we can display DC metadata.
    if (module_exists('islandora')) {
      $available_metadata_sets['dc_metadata'] = t('Basic (Dublin Core) Metadata');
    }
  }

  return $available_metadata_sets;
}