islandora_unpaywall.module

<?php
/**
 * @file
 * Unpaywall Badge
 */

/**
 * Implements hook_menu().
 */
function islandora_unpaywall_menu() {
  return array(
    'admin/islandora/tools/badges/unpaywall' => array(
      'title' => 'Unpaywall',
      'description' => 'Configure Unpaywall settings.',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('islandora_unpaywall_admin_form'),
      'access arguments' => array('administer site configuration'),
      'type' => MENU_LOCAL_TASK,
      'file' => 'includes/admin.form.inc',
    ),
  );
}

/**
 * Implements hook_block_info().
 */
function islandora_unpaywall_block_info() {
  return array(
    'islandora_unpaywall_badge' => array(
      'visibility' => BLOCK_VISIBILITY_LISTED,
      'pages' => 'islandora/object/*',
      'cache' => DRUPAL_CACHE_PER_PAGE,
      'info' => t('Islandora Unpaywall Link'),
    ),
  );
}

/**
 * Implements hook_block_view().
 */
function islandora_unpaywall_block_view($delta = '') {
  module_load_include('inc', 'islandora_badges', 'includes/utilities');
  $to_render = array();

  if ($delta == 'islandora_unpaywall_badge') {
    $object = menu_get_object('islandora_object', 2);
    if ($object) {
      // Check CModel against Badges configuration.
      if (islandora_badges_show_for_cmodel($object)) {
        // Check for PDF datastream; only run if PDF does not exist.
        if (!$object['PDF']) {
          $doi = islandora_badges_get_doi($object);
          if ($doi) {
            // Get variables and generate URL for API call.
            $email = variable_get('islandora_unpaywall_email', 'email@example.com');
            if ($email == 'email@example.com' || $email == '') {
              drupal_set_message(t('The Unpaywall API requires a valid email address. Set one in the Islandora Unpaywall configuration.'), 'warning');
            }
            $url = variable_get('islandora_unpaywall_api_endpoint', 'https://api.unpaywall.org/v2/');
            $request_url = $url . $doi . '?email=' . $email;
            // Make the request and get results!
            $result_json = drupal_http_request($request_url);
            if (!isset($result_json->error)) {
              $result_array = json_decode($result_json->data, TRUE);
              $result_free_url = $result_array['best_oa_location']['url'];
            }
          }
        }
      }
    }
  }

  if (isset($result_free_url)) {
    global $base_url;
    // If Unpaywall points to the current website, do not display block.
    if (strpos($result_free_url, $base_url) !== 0) {
      $link_text = variable_get('islandora_unpaywall_linktext', 'Link to PDF');
      $to_render['content'] = '<div class="unpaywall"><a href="' . $result_free_url . '" target="_blank">' . $link_text . '</a></div>';
    }
  }
  return $to_render;
}