islandora_conditional_access_rights.module

<?php

/**
 * @file
 * islandora_conditional_access_rights
 *
 *
 *  Copyright 2017-2019 Leiden University Library
 *
 *  This file is part of islandora_conditional_access_rights.
 *
 *  islandora_conditional_access_rights 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */


// Permissions.
define('ISLANDORA_CONDITIONAL_ACCESS_RIGHTS_ADMIN_PERMISSION', 'Islandora conditional access rights admin permission');
define('ISLANDORA_CONDITIONAL_ACCESS_RIGHTS_FOR_OBJECT_PERMISSION', 'Islandora conditional access rights for object permission');

/**
 * Implements hook_init().
 */
function islandora_conditional_access_rights_init() {
  $tnaccessrestricted = variable_get('islandora_conditional_access_rights_tn_url');
  if ($tnaccessrestricted) {
    drupal_add_js(array('conditional_access_rights' => array('tn_access_restricted' => $tnaccessrestricted)), array('type' => 'setting'));
    drupal_add_js(drupal_get_path('module', 'islandora_conditional_access_rights') . '/js/conditional_access_rights.js');
  }
}

/**
 * Implements hook_menu().
 */
function islandora_conditional_access_rights_menu() {
  $items = array();
  $items['admin/islandora/tools/islandora_conditional_access_rights'] = array(
    'title' => 'Islandora Conditional Access Rights',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_conditional_access_rights_admin_form'),
    'access arguments' => array(ISLANDORA_CONDITIONAL_ACCESS_RIGHTS_ADMIN_PERMISSION),
    'file' => 'includes/admin.form.inc',
  );
  $items['islandora/object/%islandora_object/manage/access_rights'] = array(
    'title' => 'Conditional Access Rights',
    'type' => MENU_LOCAL_TASK,
    'weight' => 0,
    'page callback' => 'drupal_get_form',
    'page arguments' => array('access_rights_view_form', 2),
    'access arguments' => array(ISLANDORA_CONDITIONAL_ACCESS_RIGHTS_FOR_OBJECT_PERMISSION),
    'file' => 'includes/object.form.inc',
  );
  $items['islandora/api/access_v1/%'] = array(
    'page callback' => 'islandora_conditional_access_rights_access_api_object',
    'page arguments' => array(3),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
    'file' => 'includes/accessapi.inc',
  );
  $items['islandora/api/access_v1/%/datastream/%'] = array(
    'page callback' => 'islandora_conditional_access_rights_access_api_datastream',
    'page arguments' => array(3, 5),
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
    'file' => 'includes/accessapi.inc',
  );

  return $items;
}

/**
 * Implements hook_permission().
 */
function islandora_conditional_access_rights_permission() {
  return array(
    ISLANDORA_CONDITIONAL_ACCESS_RIGHTS_ADMIN_PERMISSION => array(
      'title' => t('Administer configuration'),
    ),
    ISLANDORA_CONDITIONAL_ACCESS_RIGHTS_FOR_OBJECT_PERMISSION => array(
      'title' => t('See object\'s access rights'),
    ),
  );
}


/**
 * Implements hook_detail_tools_block_view().
 * This hook is used inside the templates to display the detail tools block with buttons.
 */
function islandora_conditional_access_rights_detail_tools_block_view() {
  $block = array();

  $configlocation = variable_get('islandora_conditional_access_rights_config_location');
  if (!$configlocation) {
    return $block;
  }

  module_load_include('inc', 'islandora', 'includes/utilities');
  module_load_include('inc', 'islandora_conditional_access_rights', 'includes/access_rights_settings');

  if (arg(1) == 'object' && islandora_is_valid_pid(arg(2))) {
    drupal_add_css(drupal_get_path('module', 'islandora_conditional_access_rights') . '/css/details_tools.css');
    drupal_add_js(drupal_get_path('module', 'islandora_conditional_access_rights') . '/js/details_tools.js');

    $obj = islandora_object_load(arg(2));

    // List of downloadable datastreams.
    $units = array( 'bytes', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB');
    $url = current_path();
    $dsidswlabel = islandora_conditional_access_rights_downloadable_dsids_with_label($obj);
    $additional = '';
    $hasfiles = FALSE;
    $additional .= '<h3>Download</h3>';
    if (count($dsidswlabel) > 0) {
      $additional .= '<table class="download"><tbody>';
      foreach ($dsidswlabel as $dsid => $label) {
        if (isset($obj[$dsid])) {
          $hasfiles = TRUE;
          $url = url('islandora/object/'.$obj->id.'/datastream/'.$dsid.'/download');
          $size = $obj[$dsid]->size;
          $power = $size > 0 ? floor(log($size, 1024)) : 0;
          $size = number_format($size / pow(1024, $power), ($power > 0)?1:0) . ' ' . $units[$power];
          $additional .= "<tr data-download=\"$url\"><td>$label</td><td>$size</td></tr>";
        }
      }
      $additional .= '</tbody></table>';
    }
    if (!$hasfiles) {
      $additional .= '<DIV>' . t('No downloads accessible.') . '</DIV>';
    }

    // Describe the access rights.
    $access = islandora_conditional_access_rights_access_description($obj);
    if ($access && count($access) > 0) {
      $additional .= '<TABLE class="access">';
      $additional .= '<TBODY>';
      if (isset($access['accesstext']) && strlen($access['accesstext']) > 0) {
        $additional .= '<TR><TH class="accesstitle">'.t('Restriction on access').'</TH></TR>';
        $additional .= '<TR><TD class="accesscontent">'.$access['accesstext'].'</TD></TR>';
      }
      if ((isset($access['accessimage']) && strlen($access['accessimage']) > 0) || (isset($access['accessusetext']) && strlen($access['accessusetext']) > 0)) {
        $additional .= '<TR><TH class="usetitle">'.t('Use and reproduction').'</TH></TR><TR>';
        $additional .= '<TD class="usecontent">';
        if (isset($access['accessusetext'])) {
          $additional .= $access['accessusetext'];
        }
        if (isset($access['accesslink']) && strlen($access['accesslink']) > 0) {
          $additional .= '<a href="'.$access['accesslink'].'" target="_blank" rel="license">';
        }
        $additional .= '<BR/><img class="accessimage" src="'.$access['accessimage'].'">';
        if (isset($access['accesslink'])) {
          $additional .= '</a>';
        }
        $additional .= '</TD></TR>';
      }
      $additional .= '</TBODY></TABLE>';
    }
    $additional = '<DIV class="menu">' . $additional . '</DIV>';

    $additional = '<DIV class="download-additional">' . $additional . '</DIV>';

    // Put this in a item list.
    $block['list'] = array(
      '#type' => 'ul',
      '#attributes' => array('class' => array('dc-detail-tools', 'detail-tools')),
      '#items' => array(
        array(
          'data' => l(
                      '<span>download</span><i class="fa fa-download" aria-hidden="true"></i>',
                      $url,
                      array('attributes' => array('title' => 'download'),'html' => TRUE)
                    ),
        ),
      ),
      '#theme' => 'item_list',
    );
    $block['downloadadditional'] = array(
      '#type' => 'markup',
      '#markup' => $additional,
    );
  }
  return $block;
}

/**
 * Implements hook_preprocess()
 **/
function islandora_conditional_access_rights_preprocess(&$variables, $hook) {
  if ($hook === 'islandora_book_book' || $hook === 'islandora_newspaper_issue') {
    // pages of a book are retrieved with a server ip address, thus can not check if pages are within IP range...
    // do it here... but only if book is IP range dependent.
    if (isset($variables['object']) && isset($variables['viewer_id'])) {
      $configlocation = variable_get('islandora_conditional_access_rights_config_location');
      if (!$configlocation) {
        return NULL;
      }
      module_load_include('inc', 'islandora_conditional_access_rights', 'includes/access_rights_settings');

      $object = $variables['object'];
      $config = islandora_conditional_access_rights_get_configuration($configlocation);
      $settings = islandora_conditional_access_rights_get_access_settings_from_object_or_parent($object, $config);
      if (!(isset($settings['_ip_dependent']) && $settings['_ip_dependent'])) {
        if (isset($settings['deny_access_to_dsid'])) {
          if (in_array('ALL', $settings['deny_access_to_dsid']) || in_array('JP2', $settings['deny_access_to_dsid'])) {
            $variables['viewer_id'] = NULL;
          }
        }
        return;
      }

      $pages = $variables['viewer_params']['pages'];
      $newpages = array();
      global $user;
      foreach ($pages as $pageid => $pageinfo) {
        $pageobj = islandora_object_load($pageid);
        $access = _islandora_conditional_access_rights_islandora_datastream_access_on_object($pageobj, 'JP2', $user);
        if ($access !== FALSE) {
          $newpages[$pageid] = $pageinfo;
        }
      }
      $variables['viewer_params']['pages'] = $newpages;
      if (count($newpages) == 0) {
        // remove the viewer if not pages are available.
        $variables['viewer_id'] = NULL;
      }
    }
  }
}

/**
 * Implements hook_islandora_object_access($op, $object, $user)
 **/
function islandora_conditional_access_rights_islandora_object_access($op, $object, $user) {
  if ($op === ISLANDORA_VIEW_OBJECTS) {
    $configlocation = variable_get('islandora_conditional_access_rights_config_location');
    if (!$configlocation) {
      return NULL;
    }

    module_load_include('inc', 'islandora_conditional_access_rights', 'includes/access_rights_settings');

    return islandora_conditional_access_rights_accessible_object($object);
  }
  return NULL;
}

/**
 * Implements hook_islandora_datastream_access()
 **/
function islandora_conditional_access_rights_islandora_datastream_access($op, $islandora_datastream, $user) {
  if ($op === ISLANDORA_VIEW_OBJECTS) {
    $configlocation = variable_get('islandora_conditional_access_rights_config_location');
    if (!$configlocation) {
      return NULL;
    }

    $obj = $islandora_datastream->parent;
    $dsid = $islandora_datastream->id;

    return _islandora_conditional_access_rights_islandora_datastream_access_on_object($obj, $dsid, $user);
  }
  return NULL;
}

function _islandora_conditional_access_rights_islandora_datastream_access_on_object($obj, $dsid, $user) {
  module_load_include('inc', 'islandora_conditional_access_rights', 'includes/access_rights_settings');
  // Check if the datastream is restricted.
  $restricted = islandora_conditional_access_rights_restricted_dsids($obj);
  if (in_array($dsid, $restricted)) {
    // This datastream is restricted and cannot be accessed.
    return FALSE;
  }

  // Check if the datastream is allowed.
  $allowed = islandora_conditional_access_rights_accessible_dsids($obj);
  if (in_array($dsid, $allowed)) {
    // This datastream is allowed and can be accessed.
    return TRUE;
  }

  // We don't know if this datastream is allowed or restricted, so let someone else handle it.
  return NULL;
}

/**
 * Implements hook_flush_caches().
 */
function islandora_conditional_access_rights_flush_caches() {
  return array('cache_islandora_conditional_access_rights_config','cache_islandora_conditional_access_rights_md_value');
}

/**
 * Implements hook_boot().
 */
function islandora_conditional_access_rights_boot() {
  // disable caching for islandora objects
  drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

  $configlocation = variable_get('islandora_conditional_access_rights_config_location');
  if (!$configlocation) {
    return;
  }

  $islandora_object_prefix = 'islandora/object/';
  $strlen_islandora_object_prefix = strlen($islandora_object_prefix);
  if (substr(current_path(), 0, $strlen_islandora_object_prefix) === $islandora_object_prefix) {
    module_load_include('inc', 'islandora', 'includes/utilities');
    list($objectid) = explode("/", substr(current_path(), $strlen_islandora_object_prefix));
    if (islandora_is_valid_pid($objectid)) {
      $object = islandora_object_load($objectid);
      if ($object) {
        module_load_include('inc', 'islandora_conditional_access_rights', 'includes/access_rights_settings');
        module_load_include('inc', 'islandora_conditional_access_rights', 'includes/config');

        $config = islandora_conditional_access_rights_get_configuration($configlocation);
        $settings = islandora_conditional_access_rights_get_access_settings_from_object_or_parent($object, $config);

        if (isset($settings['_ip_dependent']) && $settings['_ip_dependent']) {
          drupal_page_is_cacheable(FALSE);
        }
      }
    }
  }
}

/**
 * Implements hook_islandora_imagecache_default_icon_alter.
 * Alter the default Thumbnail used by islandora imageacache.
 *
 * @param string $themed_image
 *   The url to the styled image.
 * @param string $style
 *   The image style machine name.
 */
function islandora_conditional_access_rights_islandora_imagecache_default_icon_alter(&$themed_image, &$style) {
  // Use the tn_restricted_access.gif from this module.
  $dir = drupal_get_path('module', 'islandora_conditional_access_rights');
  $path = file_create_url("$dir/images/tn_restricted_access.gif");
  $uri = imagecache_external_generate_path($path);
  $themed_image = image_style_url($style, $uri);
}