islandora/islandora.module

<?php

/*
 * @file islandora.module
 * defines paths (drupal menu items) as entry points and acts as a hub for dispatching tasks to other modules.
 * 
 * 
 * This file is part of Islandora.
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with the program.  If not, see <http ://www.gnu.org/licenses/>.
 */


//Permissions
define('FEDORA_VIEW', 'view fedora repository');
define('FEDORA_METADATA_EDIT', 'edit fedora metadata');
define('FEDORA_ADD_DS', 'add fedora datastreams');
define('FEDORA_INGEST', 'ingest fedora objects');
define('FEDORA_PURGE', 'delete fedora objects and datastreams');
define('FEDORA_MODIFY_STATE', 'modify fedora state');
define('FEDORA_MANAGE', 'manage fedora items');

//hooks
define('ISLANDORA_VIEW_HOOK', 'islandora_view_object');
define('ISLANDORA_EDIT_HOOK', 'islandora_edit_object');

/**
 * Implementation of hook_menu. 
 * we need some standard entry points so we can have consistent urls for different Object actions
 */
function islandora_menu() {
  $items = array();

  $items['admin/islandora'] = array(
    'title' => 'Islandora Configuration',
    'description' => "Configure Islandora's interaction with Fedora",
    'access arguments' => array('administer site configuration'),
    'type' => MENU_NORMAL_ITEM,
  );
  $items['admin/islandora/configure'] = array(
    'title' => 'Islandora Configuration',
    'description' => 'Enter the Islandora collection information here.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_repository_admin'),
    'file' => 'admin/islandora.admin.inc',
    'access arguments' => array('administer site configuration'),
    'type' => MENU_NORMAL_ITEM,
    'weight' => -1,
  );

  $items['islandora/ingest/%'] = array(
    'title' => 'Ingest object',
    'page callback' => 'islandora_ingest_callback',
    'page arguments' => array(2),
    'file' => 'includes/ingest-menu.inc',
    'type' => MENU_CALLBACK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_INGEST),
  );

  $items['islandora'] = array(
    'title' => 'Islandora Repository',
    'page callback' => 'islandora_view_default_object',
    'type' => MENU_NORMAL_ITEM,
    'access arguments' => array(FEDORA_VIEW),
  );

  $items['islandora/object/%'] = array(
    'title' => 'Repository',
    'page callback' => 'islandora_view_object',
    'page arguments' => array(2),
    'type' => MENU_NORMAL_ITEM,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_VIEW),
  );


  $items['islandora/object/%/view'] = array(
    'title' => 'View',
    'page arguments' => array(2),
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_VIEW),
    'weight' => -10
  );
  $items['islandora/object/%/view/default'] = array(
    'title' => 'View',
    'page callback' => 'islandora_view_object',
    'page arguments' => array(2),
    'type' => MENU_LOCAL_TASK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_VIEW),
    'weight' => -10,
  );

  $items['islandora/object/%/manage'] = array(
    'title' => 'Manage',
    'page callback' => 'islandora_edit_object',
    'page arguments' => array(2),
    'type' => MENU_LOCAL_TASK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_MODIFY_STATE),
  );

  $items['islandora/object/%/manage/datastreams'] = array(
    'title' => 'Datastreams',
    //'page callback' => 'islandora_edit_object',
    'page arguments' => array(2),
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_PURGE),
    'weight' => -10,
  );

  $items['islandora/object/%/manage/properties'] = array(
    'title' => 'Properties',
    'page callback' => 'drupal_get_form',
    'file' => 'includes/object_properties.inc',
    'page arguments' => array('islandora_edit_properties_form', 2),
    'type' => MENU_LOCAL_TASK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_MODIFY_STATE),
    'weight' => -5,
  );

  $items['islandora/object/%/delete'] = array(
    'title' => 'Delete object',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_purge_object', 2),
    'type' => MENU_CALLBACK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_PURGE),
  );

  $items['islandora/object/%/manage/datastreams/add'] = array(
    'title' => 'Add a datastream',
    'file' => 'includes/datastream.inc',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_add_datastream_form', 2),
    'type' => MENU_NORMAL_ITEM,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_ADD_DS)
  );

  $items['islandora/object/%/manage/datastreams/add/autocomplete'] = array(
    'file' => 'includes/datastream.inc',
    'page callback' => 'islandora_datastream_autocomplete_callback',
    'page arguments' => array(2),
    'type' => MENU_CALLBACK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_ADD_DS)
  );

  $items['islandora/object/%/datastream/%'] = array(
    'title' => 'View datastream',
    'page callback' => 'islandora_datastream_as_attachment',
    'page arguments' => array(2, 4),
    'type' => MENU_CALLBACK,
    'file' => 'includes/datastream.inc',
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_VIEW),
  );

  $items['islandora/object/%/datastream/%/view'] = array(
    'title' => 'View datastream',
    'page callback' => 'islandora_datastream_as_attachment',
    'page arguments' => array(2, 4),
    'type' => MENU_CALLBACK,
    'file' => 'includes/datastream.inc',
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_VIEW),
  );

  $items['islandora/object/%/datastream/%/download'] = array(
    'title' => 'Download datastream',
    'page callback' => 'islandora_datastream_as_attachment',
    'page arguments' => array(2, 4),
    'type' => MENU_CALLBACK,
    'file' => 'includes/datastream.inc',
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_VIEW),
  );

  $items['islandora/object/%/datastream/%/edit'] = array(
    'title' => 'Edit datastream',
    'page callback' => 'islandora_edit_datastream',
    'page arguments' => array(2, 4),
    'type' => MENU_CALLBACK,
    'file' => 'includes/datastream.inc',
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_METADATA_EDIT),
  );

  $items['islandora/object/%/datastream/%/delete'] = array(
    'title' => 'Purge data stream',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_purge_datastream', 2, 4),
    'type' => MENU_CALLBACK,
    'access callback' => 'islandora_access_callback',
    'access arguments' => array(2, FEDORA_PURGE),
  );

  return $items;
}

function islandora_admin_paths_alter(&$paths) {

  $paths['*/manage*'] = TRUE;
}

/**
 * Implements hook_menu_local_tasks_alter().
 */
function islandora_menu_local_tasks_alter(&$data, $router_item, $root_path) {
  // Add action link 'islandora/object/%/manage/datastreams'.
  if ($root_path == 'islandora/object/%/manage') {
    $object_id = $router_item['page_arguments'][0];
    $item = menu_get_item("islandora/object/$object_id/manage/datastreams/add");
    if ($item['access']) {
      $data['actions']['output'][] = array(
        '#theme' => 'menu_local_action',
        '#link' => $item,
      );
    }
  }
}

/**
 * determines whether we can see the object or not
 * checks PID namespace permissions, and user permissions
 * @global object $user
 * @param string $op
 * @param string $pid
 *
 *  @return boolean 
 */
function islandora_access_callback($pid = NULL, $perm = NULL) {
  if(!$pid || !$perm) {
    return FALSE;
  }

  $isRestricted = variable_get('islandora_namespace_restriction_enforced', FALSE);
  
  if (!$isRestricted) {
    $namespace_access = TRUE;
  }
  else {
    $pid_namespace = substr($pid, 0, strpos($pid, ':') + 1); //Get the namespace (with colon)
    $allowed_namespaces = explode(" ", variable_get('islandora_pids_allowed', 'default: demo: changeme: islandora: ilives: islandora-book: books: newspapers: '));

    $namespace_access = in_array($pid_namespace, $allowed_namespaces);
  }

  return ($namespace_access && user_access($perm));
}

/**
 * Gives the option of deleting or purging and object.
 * 
 * The default behaviour is to purge the object to reduce maintenance.
 * If a solution pack wants to change this behaviour and have the object set to deleted then
 * it can respond to the 'islandora_pre_purge_object' hook with an array containing the pair 
 * 'delete' => TRUE. 
 * Once the object has been deleted/purged then a second call lets the solution packs know that
 * the object has been dealt with. In this call the object id and content models are sent out so
 * that the solution packs can act on this news. There is no guarantee that the object still exists
 * and so the object object isn't sent.
 * 
 * @param string $object_id
 *   ID of the object
 * @return type 
 */
function islandora_purge_object_submit($form, &$form_state) {
  $object_id = $form_state['values']['pid'];
  $collection = $form_state['values']['col'];

  module_load_include('inc', 'islandora', 'RestConnection');
  global $user;
  if (!isset($object_id)) {
    drupal_set_message(t('Cannot remove object, object id not set'));
    return;
  }
  try {
    $restConnection = new RestConnection($user);
    $fedora_object = new FedoraObject($object_id, $restConnection->repository);
  } catch (Exception $e) {
    drupal_set_message(t('Error getting Islandora object %s %e', array('%s' => $object_id, '%e' => $e)), 'error');
    return "";
  }
  if (!isset($fedora_object)) {
    drupal_set_message(t('Could not remove object, object not found'));
    return;
  }
  $content_models = $fedora_object->models;
  $arr = module_invoke_all('islandora_pre_purge_object', $fedora_object); //notify modules of pending deletion
  if (isset($arr['delete']) && $arr['delete']) {
    try {
      $fedora_object->delete();
    } catch (Exception $e) {
      drupal_set_message(t('Error deleting Islandora object %s %e', array('%s' => $object_id, '%e' => $e)), 'error');
      return "";
    }
  }
  else {
    try {
      $restConnection->repository->purgeObject($object_id);
    } catch (Exception $e) {
      drupal_set_message(t('Error purging Islandora object %s %e', array('%s' => $object_id, '%e' => $e)), 'error');
      return "";
    }
  }
  module_invoke_all('islandora_post_purge_object', $object_id, $content_models);  //notify modules post deletion
  drupal_goto($collection);
}

function islandora_purge_object($form, &$form_state, $pid) {

  module_load_include('inc', 'islandora', 'RestConnection');
  module_load_include('inc', 'islandora', 'includes/datastream');

  $connection = new RestConnection();
  $object = $connection->repository->getObject($pid);
  $parent = islandora_datastream_get_parents($object);
  $key = array_keys($parent);

  if (count($key) > 0) {
    $redirect = "islandora/object/$key[0]";
  }
  else {
    $redirect = "islandora";
  }


  // Always provide entity id in the same form key as in the entity edit form.
  $form['pid'] = array('#type' => 'value', '#value' => $pid);
  $form['col'] = array('#type' => 'value', '#value' => $redirect);

  return confirm_form($form,
    t('Are you sure you want to delete %title?', array('%title' => $object->label)),
    "islandora/object/$pid",
    t('This action cannot be undone.'),
    t('Delete'),
    t('Cancel')
  );
}

/**
 * returns an array listing object types provided by sub modules
 * @return array 
 */
function islandora_get_types() {
  return module_invoke_all('islandora_get_types');
}

function islandora_init() {
  if (path_is_admin(current_path())) {
    drupal_add_css(drupal_get_path('module', 'islandora') . '/css/islandora.admin.css');
  }
}

/**
 * a function to call other modules edit page.  If there are not any modules
 * that handle this function this module will build a default page.
 * @global object $user
 * @param string $object_id
 * @return string 
 */
function islandora_edit_object($object_id) {
  module_load_include('inc', 'islandora', 'RestConnection');
  global $user;
  try {
    $restConnection = new RestConnection($user);
    $fedora_object = new FedoraObject($object_id, $restConnection->repository);
  } catch (Exception $e) {
    drupal_set_message(t('Error getting Islandora object %s', array('%s' => $object_id)), 'error');
    return"";
  }
  drupal_alter('islandora_edit_object', $fedora_object);
  $arr = module_invoke_all('islandora_edit_object', $fedora_object);
  $output = "";
  foreach ($arr as $key => $value) {
    $output .= $value; //if we have multiple modules handle one cmodel we need to iterate over multiple
  }
  //we could do another module invoke all here to build the edit tab with a default implemented in this module?
  return $output;
}

/**
 * edit properties form
 * @param type $object_id
 * @return string 
 */
function islandora_edit_properties($object_id) {
  $object = islandora_get_object($object_id);
  if (isset($object)) {
    module_load_include('inc', 'islandora', 'includes/object_properties');
    $form = drupal_get_form('islandora_edit_properties_form', $object);
    drupal_set_title($object->label);
    return drupal_render($form);
  }
  return "";
}

/**
 * builds a default page for the edit tab
 *
 * @param object $fedora_object 
 *   A tuque Fedora Object
 */
function islandora_islandora_edit_object($fedora_object) {
  $supported_models = islandora_get_types();
  $output = "";
  foreach ($fedora_object->models as $model) {
    if (isset($supported_models[$model][ISLANDORA_EDIT_HOOK]) && $supported_models[$model][ISLANDORA_EDIT_HOOK] == TRUE) {//another module is handling the view
      return;
    }
  }
  $output = theme('islandora_default_edit', array('islandora_object' => $fedora_object));
  return array('Default Edit output' => $output);
}


function islandora_purge_datastream($form, &$form_state, $object_id, $datastream_id) {
  module_load_include('inc', 'islandora', 'RestConnection');
  module_load_include('inc', 'islandora', 'includes/datastream');

  $connection = new RestConnection();
  $object = $connection->repository->getObject($object_id);
  $datastream = $object->getDatastream($datastream_id);

  $redirect = "islandora/object/$object_id";
  
  // Always provide entity id in the same form key as in the entity edit form.
  $form['pid'] = array('#type' => 'value', '#value' => $object_id);
  $form['dsid'] = array('#type' => 'value', '#value' => $datastream_id);
  $form['col'] = array('#type' => 'value', '#value' => $redirect);

  return confirm_form($form,
    t('Are you sure you want to delete the %dsid datastream?', array('%dsid' => $datastream->id)),
    "islandora/object/$object_id",
    t('This action cannot be undone.'),
    t('Delete'),
    t('Cancel')
  );
}

/**
 * Gives the option of purging or deleting a datastream.
 * 
 * The default behaviour is to purge the datastream but this can be overridden using the 
 * 'islandora_pre_purge_datastream' hook. The returned array can include a 'block' => TRUE 
 * pair which will prevent the datastream from being deleted if it particularly needed for 
 * a certain function. Returning 'delete' => TRUE will cause the datastream to be put into 
 * a deleted state.
 * 
 * @param string $object_id
 *   ID of the object
 * @param string $datastream_id
 *   ID of the datastream
 *   
 */
function islandora_purge_datastream_submit($form, &$form_state) {
  module_load_include('inc', 'islandora', 'RestConnection');
  $object_id = $form_state['values']['pid'];
  $datastream_id = $form_state['values']['dsid'];
  global $user;
  if (!isset($datastream_id)) {
    drupal_set_message(t('Cannot remove datastream, datastream id not set'));
    return;
  }
  try {
    $restConnection = new RestConnection($user);
    $fedora_object = new FedoraObject($object_id, $restConnection->repository);
  } catch (Exception $e) {
    drupal_set_message(t('Error getting Islandora object %s %e', array('%s' => $object_id, '%e' => $e)), 'error');
    return "";
  }
  if (!isset($fedora_object)) {
    drupal_set_message(t('Could not remove object, object not found'));
    return;
  }
  if (!isset($fedora_object)) {
    drupal_set_message(t('Could not remove object, object not found'));
    return;
  }
  $arr = module_invoke_all('islandora_pre_purge_datastream', $fedora_object, $datastream_id); //notify modules of pending deletion so we can update rels etc
  if (isset($arr['block']) && $arr['block']) {
    drupal_set_message(t('Purging of the %d datastream was blocked', array('%d' => $datastream_id)), 'warning');
    return;
  }
  if (isset($arr['delete']) && $arr['delete']) {
    try {
      $datastream = new FedoraDatastream($datastream_id, $fedora_object, $restConnection->repository);
      $datastream->state = 'D';
    } catch (Exception $e) {
      drupal_set_message(t('Error deleting %s datastream from Islandora object %o %e', array('%s' => $datastream_id, '%o' => $object_id, '%e' => $e)), 'error');
      return;
    }
  }
  else {
    try {
      $fedora_object->purgeDatastream($datastream_id);
    } catch (Exception $e) {
      drupal_set_message(t('Error purging %s datastream from Islandora object %o %e', array('%s' => $datastream_id, '%o' => $object_id, '%e' => $e)), 'error');
      return;
    }
  }
  module_invoke_all('islandora_post_purge_datastream', $fedora_object, $datastream_id);  //notify modules post deletion
  drupal_set_message(t('%d datastream sucessfully purged from Islandora object %o', array('%d' => $datastream_id, '%o' => $object_id)));
  drupal_goto('islandora/object/' . $object_id);
}

function islandora_view_default_object() {
  $pid = variable_get('islandora_repository_pid', 'islandora:root');
  drupal_goto("islandora/object/$pid");
}

/**
 * The view entry point.  modules should implement hook_islandora_view_object for the Fedora Content models that
 * their modules want to provide a view for.
 * @global object $user
 * @param string $object_id
 * 
 * @return string 
 */
function islandora_view_object($object_id = NULL) {
  module_load_include('inc', 'islandora', 'includes/Breadcrumbs');
  drupal_set_breadcrumb(islandora_get_breadcrumbs($object_id));
  //return $object_id;
  if (!isset($object_id)) {
    $object_id = variable_get('islandora_repository_pid', 'islandora:root');
    //return;
  }

  $page_number = (empty($_GET['page'])) ? '1' : $_GET['page'];
  $page_size = (empty($_GET['pagesize'])) ? '10' : $_GET['pagesize'];
  module_load_include('inc', 'islandora', 'RestConnection');
  global $user;
  try {
    $restConnection = new RestConnection($user);
    $fedora_object = new FedoraObject($object_id, $restConnection->repository);
  } catch (Exception $e) {
    drupal_set_message(t('Error getting Islandora object %s', array('%s' => $object_id)), 'error');
    return"";
  }
  drupal_alter('islandora_object', $fedora_object); //modify object if required before it is passed along
  $arr = module_invoke_all('islandora_view_object', $fedora_object, $user, $page_number, $page_size); //allow submodules to decide how to handle content base on object type
  if (empty($arr)) {
    //TODO: make sure we iterate over the array as they will be more then one cmodel per object
    drupal_set_message(t('there was an error loading the view for islandora object %s', array('%s' => $object_id)), 'error');
    return "";
  }
  arsort($arr);
  drupal_alter('islandora_display', $arr);
  $output = "";
  foreach ($arr as $key => $value) {
    $output .= $value; //if we have multiple modules handle one cmodel we need to iterate over multiple
  }
  return $output;
}

/**
 * the default view hook.  If there are no modules registered to handle this objects cmodels or there are 
 * not any cmodels specified this will create a default display.
 * @param string $object_id
 * @return string 
 */
function islandora_islandora_view_object($object) {
  $supported_models = islandora_get_types();
  $output = "";
  foreach ($object->models as $model) {
    if (isset($supported_models[$model][ISLANDORA_VIEW_HOOK]) && (boolean) $supported_models[$model][ISLANDORA_VIEW_HOOK] === TRUE) {//another module is handling the view
      return;
    }
  }
  $output = theme('islandora_default', array('islandora_object' => $object));
  return array('Default Output' => $output);
}

/**
 * Theme registry function
 * @return array
 */
function islandora_theme() {
  return array(
    'islandora_default' => array(
      'template' => 'islandora-object',
      'variables' => array('islandora_object' => NULL),
    ),
    'islandora_default_edit' => array(
      'template' => 'islandora-object-edit',
      'variables' => array('islandora_object' => NULL),
    ),
  );
}

/**
 * drupal hook_permissions function
 * @return array
 */
function islandora_permission() {
  return array(
    FEDORA_VIEW => array(
      'title' => t('View Fedora Repository objects and datastreams'),
      'description' => t('Users with this permission will be allowed to view Fedora objects and datastreams.  Unless Fedora XACML security policies limits this functionality to certain objects.')
    ),
    FEDORA_ADD_DS => array(
      'title' => t('Add Fedora streams to Fedora objects'),
      'description' => t('Users with this permission will be allowed to add datastreams to Fedora objects.  Unless Fedora XACML security policies limits this functionality to certain objects.')
    ),
    FEDORA_METADATA_EDIT => array(
      'title' => t('Edit Fedora Metadata'),
      'description' => t('Users with this permission will be allowed to edit Fedora Metadata streams')
    ),
    FEDORA_INGEST => array(
      'title' => t('Create new Fedora objects'),
      'description' => t('Users with this permission will be allowed to create new objects in the Fedora repository')
    ),
    FEDORA_PURGE => array(
      'title' => t('Permanently remove objects from the Fedora repository'),
      'description' => t('Users with this permission will be allowed to Permantly remove objects from the Fedora repository.')
    ),
    FEDORA_MODIFY_STATE => array(
      'title' => t('Change a Fedora objects state'),
      'description' => t('Users with this permission will be allowed to change a Fedora objects state.')
    ),
    FEDORA_MANAGE => array(
      'title' => t('View Fedora Manage tabs'),
      'description' => t('Users with this permission will be allowed to view fedora manage manage tabs.')
    )
  );
}

/**
 * preprocess for the default view template
 * @global string $base_url
 * @param array $variables 
 */
function islandora_preprocess_islandora_default(&$variables) {
  drupal_add_js('misc/form.js');
  drupal_add_js('misc/collapse.js');
  $islandora_object = $variables['islandora_object'];
  module_load_include('inc', 'islandora', 'includes/islandora_dublin_core');
  module_load_include('inc', 'islandora', 'includes/utilities');
  module_load_include('inc', 'islandora', 'includes/datastream');

  $variables['parent_collections'] = islandora_datastream_get_parents($islandora_object);

  $datastreams = array();
  foreach ($islandora_object as $ds) {
    $pid = $islandora_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'] = l($label, $download_path);
    $datastreams[$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'] = strtolower(preg_replace('/[^A-Za-z0-9]/', '-', $id));
  }
  $variables['datastreams'] = $datastreams;
  try {
    $dc = $islandora_object['DC']->content;
    //$dc_xml = simplexml_load_string($dc);
    $dc_object = Dublin_Core::import_from_xml_string($dc);
  } catch (Exception $e) {
    drupal_set_message(t('Error retrieving object %s %t', array('%s' => $islandora_object->id, '%t' => $e->getMessage())), 'error');
  }
  $variables['dc_array'] = $dc_object->as_formatted_array();
  $variables['islandora_dublin_core'] = $dc_object;
  $variables['islandora_object_label'] = $islandora_object->label;
  global $base_url;
  if (isset($islandora_object['TN'])) {
    $variables['islandora_thumbnail_url'] = $base_url . '/islandora/object/' . $islandora_object->id . '/datastream/TN/view';
  }
}

/**
 * a helper function to get a connection and return an object
 * @global object $user
 * @param string $object_id
 * @return FedoraObject 
 */
function islandora_get_object($object_id) {
  module_load_include('inc', 'islandora', 'RestConnection');
  global $user;
  try {
    $restConnection = new RestConnection($user);
    $fedora_object = new FedoraObject($object_id, $restConnection->repository);
  } catch (Exception $e) {
    drupal_set_message(t('Error getting Islandora object %s', array('%s' => $object_id)), 'error');
    return NULL;
  }
  return $fedora_object;
}

/**
 * preprocess the edit template
 * @global string $base_url
 * @param array $variables 
 *   theme variables for the edit template
 */
function islandora_preprocess_islandora_default_edit(&$variables) {
  $islandora_object = $variables['islandora_object'];
  global $base_url;
  $datastreams = array();
  $variables['islandora_editmetadata_url'] = $base_url . '/islandora/edit_form/' . $islandora_object->id;
  module_load_include('inc', 'islandora', 'includes/datastream');
  module_load_include('inc', 'islandora', 'includes/utilities');
  // $variables['add_datastream_form'] = drupal_get_form('islandora_add_datastream_form', $islandora_object->id);
  $header = array(
    array('data' => t('ID')),
    array('data' => t('Label')),
    array('data' => t('Type')),
    array('data' => t('Mime type')),
    array('data' => t('Size')),
    array('data' => t('Operations'), 'colspan' => '3'),
      //array('data' => t('Delete')),
  );
  $table_attributes = array('class' => array('manage-datastreams'));
  $rows = array();
  foreach ($islandora_object as $ds) {
    $rows[] = array(
      array('class' => 'datastream-id', 'data' => l($ds->id, islandora_datastream_get_url($ds, 'view'))),
      array('class' => 'datastream-label', 'data' => $ds->label),
      array('class' => 'datastream-control', 'data' => islandora_control_group_to_human_readable($ds->controlGroup)),
      array('class' => 'datastream-mime', 'data' => $ds->mimeType),
      array('class' => 'datastream-size', 'data' => islandora_datastream_get_human_readable_size($ds)),
      array('class' => 'datastream-download', 'data' => l(t('download'), islandora_datastream_get_url($ds, 'download'))),
      array('class' => 'datstream-edit', 'data' => islandora_datastream_edit_get_link($islandora_object, $ds->id)),
      array('class' => 'datastream-delete', 'data' => l(t('delete'), $base_url . '/islandora/object/' . $islandora_object->id . '/datastream/' . $ds->id . '/delete')),
    );
  }
  $caption = $islandora_object->label . ' - ' . $islandora_object->id;
  $table = array('colgroups' => NULL, 'sticky' => TRUE, 'empty' => 'Error loading datastreams', 'caption' => $caption, 'header' => $header, 'rows' => $rows, 'attributes' => $table_attributes);
  $variables['datastream_table'] = theme_table($table);
}