islandora_solr.module

<?php

/**
 * @file
 * Implementation of Solr search for the Islandora fedora_search module.
 */

define('ISLANDORA_SOLR_SEARCH_PATH', 'islandora/search');
define('ISLANDORA_SOLR_QUERY_SPLIT_REGEX', '/(?<!\\\\) /');
define('ISLANDORA_SOLR_QUERY_FIELD_VALUE_SPLIT_REGEX', '/(?<!\\\\):/');

const ISLANDORA_SOLR_QUERY_FACET_LUCENE_ESCAPE_REGEX_DEFAULT = '/(\+|-|&&|\|\||!|\(|\)|\{|\}|\[|\]|\^| |~|\*|\?|\:|"|\\\\|\\/)/';

const ISLANDORA_SOLR_FACET_BUCKET_CLASSES_HOOK_BASE = 'islandora_solr_facet_bucket_classes';

const ISLANDORA_SOLR_BREADCRUMB_BACKEND = 'islandora_solr_breadcrumb_backend';

const ISLANDORA_SOLR_DIFFICULTIES_MESSAGE = "We are experiencing technical difficulties at this time and are working to fix the problem. Please try back later.";

// Includes functions for common db queries.
require_once dirname(__FILE__) . '/includes/db.inc';
// Includes functions for common tasks.
require_once dirname(__FILE__) . '/includes/utilities.inc';
// Includes functions to create Islandora Solr blocks.
require_once dirname(__FILE__) . '/includes/blocks.inc';
// Includes functions for advanced facet functionality.
require_once dirname(__FILE__) . '/includes/facets.inc';
// Includes functions for connecting to Solr and Luke.
require_once dirname(__FILE__) . '/includes/luke.inc';

/**
 * Implements hook_menu().
 */
function islandora_solr_menu() {
  $items['islandora/search'] = array(
    'title' => 'Search results',
    'page callback' => 'islandora_solr',
    'page arguments' => array(2, NULL),
    'access arguments' => array('search islandora solr'),
    'type' => MENU_CALLBACK,
  );
  $items['admin/islandora/search/islandora_solr'] = array(
    'title' => 'Solr index',
    'description' => 'Configure Solr index.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_solr_admin_index_settings'),
    'access arguments' => array('administer islandora solr'),
    'file' => 'includes/admin.inc',
    'type' => MENU_NORMAL_ITEM,
  );
  $items['admin/islandora/search/islandora_solr/index'] = array(
    'title' => 'Solr index',
    'description' => 'Configure Solr index.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_solr_admin_index_settings'),
    'access arguments' => array('administer islandora solr'),
    'file' => 'includes/admin.inc',
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/islandora/search/islandora_solr/settings'] = array(
    'title' => 'Solr settings',
    'description' => 'Configure Solr search settings.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_solr_admin_settings'),
    'access arguments' => array('administer islandora solr'),
    'file' => 'includes/admin.inc',
    'type' => MENU_LOCAL_TASK,
  );
  $items['admin/islandora/search/islandora_solr/breadcrumbs'] = array(
    'title' => 'Solr breadcrumbs',
    'description' => 'Configure Solr breadcrumb generation',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_solr_admin_breadcrumbs_settings'),
    'access arguments' => array('administer islandora solr'),
    'file' => 'includes/admin.inc',
    'type' => MENU_LOCAL_TASK,
  );
  $items['islandora_solr/field'] = array(
    'title' => 'Result field',
    'description' => 'Configuration for Solr result field',
    'page callback' => 'islandora_solr_admin_settings_field',
    'page arguments' => array(2, 3),
    'access arguments' => array('administer islandora solr'),
    'file' => 'includes/admin.inc',
    'type' => MENU_CALLBACK,
  );
  $items['islandora_solr/autocomplete_luke'] = array(
    'title' => 'Islandora Solr Luke autocomplete',
    'description' => 'Autocomplete callback to populate solr text fields.',
    'page callback' => '_islandora_solr_autocomplete_luke',
    'access arguments' => array('administer islandora solr'),
    'file' => 'includes/admin.inc',
    'type' => MENU_CALLBACK,
  );
  $items['admin/islandora/search/islandora_solr/settings/confirmation'] = array(
    'title' => 'Default settings restore',
    'description' => 'Confirmation form to confirm defualt settings restore',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('islandora_solr_admin_settings_default_confirm_form'),
    'access arguments' => array('administer islandora solr'),
    'file' => 'includes/admin.inc',
    'type' => MENU_CALLBACK,
  );
  if (module_exists('islandora_compound_object')) {
    $items['admin/islandora/solution_pack_config/compound_object/solr'] = array(
      'title' => 'Solr Backend',
      'description' => 'Settings form for compound object backend',
      'page callback' => 'drupal_get_form',
      'page arguments' => array('islandora_solr_compound_backend_admin_form'),
      'access arguments' => array('administer compound relationships'),
      'file' => 'includes/compound_backend.inc',
      'type' => MENU_LOCAL_TASK,
    );
  }
  return $items;
}

/**
 * Implements hook_admin_paths().
 */
function islandora_solr_admin_paths() {
  $paths = array(
    'admin/config/islandora_solr' => TRUE,
  );
  return $paths;
}

/**
 * Implements hook_permission().
 */
function islandora_solr_permission() {
  return array(
    'search islandora solr' => array(
      'title' => t('Search the Solr index'),
      'description' => t('Search for objects in the repository using Solr. This permission exposes the search blocks and allows you to see search results.'),
    ),
    'administer islandora solr' => array(
      'title' => t('Administer Solr'),
      'description' => t('Administer settings for the Solr client.'),
    ),
    'view islandora solr debug' => array(
      'title' => t('View Solr debug messages'),
      'description' => t('See printed Solr queries when debug mode is turned on.'),
    ),
  );
}

/**
 * Implements hook_theme().
 */
function islandora_solr_theme() {
  $path = drupal_get_path('module', 'islandora_solr');
  $file = 'theme.inc';

  return array(
    // Advanced solr search form/block.
    'islandora_solr_advanced_search_form' => array(
      'variables' => array(
        'form' => NULL,
      ),
    ),
    // Theme admin form.
    'islandora_solr_admin_primary_display' => array(
      'path' => $path,
      'file' => 'includes/admin.inc',
      'render element' => 'form',
    ),
    // Theme admin form fields.
    'islandora_solr_admin_fields' => array(
      'path' => $path,
      'file' => 'includes/admin.inc',
      'render element' => 'form',
    ),
    // Results page.
    'islandora_solr_wrapper' => array(
      'path' => $path . '/theme',
      'file' => $file,
      'template' => 'islandora-solr-wrapper',
      'variables' => array(
        'results' => NULL,
        'secondary_profiles' => NULL,
        'elements' => array(),
      ),
    ),
    // Default results display.
    'islandora_solr' => array(
      'path' => $path . '/theme',
      'file' => $file,
      'template' => 'islandora-solr',
      'variables' => array(
        'results' => NULL,
        'elements' => array(),
        'pids' => array(),
      ),
    ),
     // Default facet.
    'islandora_solr_facet' => array(
      'path' => $path . '/theme',
      'file' => $file,
      'template' => 'islandora-solr-facet',
      'variables' => array('buckets' => NULL, 'hidden' => FALSE, 'pid' => NULL),
    ),
     // Facet wrapper.
    'islandora_solr_facet_wrapper' => array(
      'path' => $path . '/theme',
      'file' => $file,
      'variables' => array('title' => NULL, 'content' => NULL, 'pid' => NULL),
    ),
     // Range slider.
    'islandora_solr_range_slider' => array(
      'path' => $path . '/theme',
      'file' => $file,
      'template' => 'islandora-solr-range-slider',
      'variables' => array(
        'form_key' => NULL,
        'gap' => NULL,
        'range_from' => NULL,
        'range_to' => NULL,
      ),
    ),
    'islandora_solr_search_navigation_block' => array(
      'path' => $path . '/theme',
      'file' => $file,
      'template' => 'islandora-solr-search-navigation-block',
      'variables' => array(
        'return_link' => NULL,
        'prev_link' => NULL,
        'next_link' => NULL,
        'prev_text' => NULL,
        'return_text' => NULL,
        'next_text' => NULL,
      ),
    ),
  );
}

/**
 * Implements hook_islandora_solr_primary_display().
 */
function islandora_solr_islandora_solr_primary_display() {
  return array(
    'default' => array(
      'name' => t('List (default)'),
      'module' => 'islandora_solr',
      'file' => 'includes/results.inc',
      'class' => "IslandoraSolrResults",
      'function' => "displayResults",
      'description' => t("Display search results as a list view"),
    ),
  );
}

/**
 * Page callback: Islandora Solr.
 *
 * Gathers url parameters, and calls the query builder, which prepares the query
 * based on the admin settings and url values.
 * Finds the right display and calls the IslandoraSolrRestuls class to build the
 * display, which it returns to the page.
 *
 * @global IslandoraSolrQueryProcessor $_islandora_solr_queryclass
 *   The IslandoraSolrQueryProcessor object which includes the current query
 *   settings and the raw Solr results.
 *
 * @param string $query
 *   The query string.
 *
 * @return string
 *   A rendered Solr display
 *
 * @see hook_menu()
 */
function islandora_solr($query = NULL, $params = NULL) {
  global $_islandora_solr_queryclass;
  drupal_add_css(drupal_get_path('module', 'islandora_solr') . '/css/islandora_solr.theme.css');

  // Url parameters.
  if ($params === NULL) {
    $params = $_GET;
  }
  // Get profiles.
  $primary_profiles = module_invoke_all('islandora_solr_primary_display');
  $secondary_profiles = module_invoke_all('islandora_solr_secondary_display');

  // Get the preferred display profile.
  // Order:
  // - $_GET['display'].
  // - The default primary display profile.
  // - Third choice is the base IslandoraSolrResults.
  $enabled_profiles = array();
  // Get enabled displays.
  $primary_display_array = variable_get('islandora_solr_primary_display_table', array());
  // If it's set, we take these values.
  if (isset($primary_display_array['enabled'])) {
    foreach ($primary_display_array['enabled'] as $key => $value) {
      if ($key === $value) {
        $enabled_profiles[] = $key;
      }
    }
  }
  // Set primary display.
  // Check if display param is an valid, enabled profile; otherwise, show
  // default.
  if (isset($params['display'])) {
    if (in_array($params['display'], $enabled_profiles)) {
      $islandora_solr_primary_display = $params['display'];
    }
    else {
      // Unset invalid parameter.
      unset($params['display']);
    }
  }

  if (empty($islandora_solr_primary_display)) {
    $islandora_solr_primary_display = variable_get('islandora_solr_primary_display', 'default');
  }

  $params['islandora_solr_search_navigation'] = variable_get('islandora_solr_search_navigation', FALSE);

  // !!! Set the global variable. !!!
  $_islandora_solr_queryclass = new IslandoraSolrQueryProcessor();

  // Build and execute Apache Solr query.
  $_islandora_solr_queryclass->buildAndExecuteQuery($query, $params);

  if (empty($_islandora_solr_queryclass->islandoraSolrResult)) {
    return t('Error searching Solr index.');
  }

  // TODO: Also filter secondary displays against those checked in the
  // configuration options.
  if (isset($params['solr_profile']) && isset($secondary_profiles[$params['solr_profile']])) {
    $profile = $secondary_profiles[$_GET['solr_profile']];
  }
  elseif (isset($primary_profiles[$islandora_solr_primary_display])) {
    $profile = $primary_profiles[$islandora_solr_primary_display];
  }
  else {
    drupal_set_message(check_plain(t('There is an error in the Solr search configuration: the display profile is not found.')), 'error');
    $profile = $primary_profiles['default'];
  }

  if (isset($profile['file'])) {
    // Include the file for the display profile.
    require_once drupal_get_path('module', $profile['module']) . '/' . $profile['file'];
  }

  // Get display class and function from current display.
  $solr_class = $profile['class'];
  $solr_function = $profile['function'];

  // Check if the display's class exists.
  $use_default_display = TRUE;
  if (class_exists($solr_class)) {
    $implementation = new $solr_class();
    // Check if the display's method exists.
    if (method_exists($implementation, $solr_function)) {
      // Implement results.
      $output = $implementation->$solr_function($_islandora_solr_queryclass);
      $use_default_display = FALSE;
    }
  }

  // Class and method could not be found, so use default.
  if ($use_default_display) {
    $results_class = new IslandoraSolrResults();
    $output = $results_class->displayResults($_islandora_solr_queryclass);
  }

  // Debug dump.
  if (variable_get('islandora_solr_debug_mode', 0) && user_access('view islandora solr debug')) {
    $message = t('Parameters: <br /><pre>!debug</pre>', array('!debug' => print_r($_islandora_solr_queryclass->solrParams, TRUE)));
    drupal_set_message(filter_xss($message, array('pre', 'br')), 'status');
  }
  return $output;
}

/**
 * Check if the current context is the search results page.
 *
 * @todo Checking for display might not be the best way to do this. Need to
 *   review the way blocks are created.
 *
 * @param object $islandora_solr_query
 *   The IslandoraSolrQueryProcessor object which includes the current query
 *   settings but at the beginning of
 *   IslandoraSolrQueryProcessor::executeQuery().
 *
 * @return bool
 *   Returns TRUE if the context is the search results page. FALSE if not.
 */
function islandora_solr_results_page($islandora_solr_query) {

  if (isset($islandora_solr_query->display)) {
    return TRUE;
  }
  else {
    return FALSE;
  }
}

/**
 * Implements hook_i18n_string_info().
 */
function islandora_solr_i18n_string_info() {
  return array(
    'islandora_solr' => array(
      'title' => t('Islandora Solr'),
      'description' => t('Translatable result and facet field labels.'),
      'format' => FALSE,
      'list' => TRUE,
    ),
  );
}

/**
 * Implements hook_forms().
 */
function islandora_solr_forms($form_id, $args) {
  $forms = array();

  if (strpos($form_id, 'islandora_solr_admin') === 0) {
    module_load_include('inc', 'islandora_solr', 'includes/admin');

    // Handle two form using the same building function, but allowing each to
    // be altered separately.
    if (in_array($form_id, array(
      'islandora_solr_admin_settings_search_fields',
      'islandora_solr_admin_settings_sort_fields',
    ))) {
      $forms[$form_id] = array(
        'callback' => 'islandora_solr_admin_settings_search_or_sort_fields',
      );
    }
  }
  // Check if the form_id passed to drupal_get_form() contains the string
  // 'islandora_solr_search_date_filter_form'.
  if (strpos($form_id, 'islandora_solr_date_filter_form') !== FALSE) {
    module_load_include('inc', 'islandora_solr', 'includes/facets');
    $forms[$form_id] = array(
      'callback' => 'islandora_solr_date_filter_form',
      'callback arguments' => array($args[0]),
    );
  }

  // Check if the form_id passed to drupal_get_form() contains the string
  // 'islandora_solr_range_slider_form'.
  if (strpos($form_id, 'islandora_solr_range_slider_form') !== FALSE) {
    module_load_include('inc', 'islandora_solr', 'includes/facets');
    $forms[$form_id] = array(
      'callback' => 'islandora_solr_range_slider_form',
      'callback arguments' => array($args[0]),
    );
  }

  return $forms;
}

/**
 * Implements hook_features_api().
 */
function islandora_solr_features_api() {
  $mod_path = drupal_get_path('module', 'islandora_solr');
  return array(
    'islandora_solr_fields' => array(
      'name' => t('Islandora Solr Fields Configuration'),
      'file' => "$mod_path/includes/fields.features.inc",
      'default_hook' => 'islandora_solr_fields_features_default_fields',
      'feature_source' => TRUE,
    ),
  );
}

/**
 * Check if dismax is configured for the currently selected request handler.
 *
 * Results are cached, to reduce chatter between Drupal and Solr.
 *
 * @param bool $reset
 *   Force cache revalidation.
 *
 * @return bool
 *   TRUE if the current request handler supports dismax, FALSE if it does not.
 */
function islandora_solr_check_dismax($reset = FALSE) {
  $cache_id = 'islandora_solr_dismax';
  $cache = $reset ? FALSE : cache_get($cache_id);

  if (!$cache) {
    module_load_include('inc', 'islandora_solr', 'includes/admin');
    $solr_url = variable_get('islandora_solr_url', 'localhost:8080/solr');
    $handler = variable_get('islandora_solr_request_handler', FALSE);
    $dismax = _islandora_solr_check_dismax($solr_url, $handler);
    cache_set($cache_id, $dismax, 'cache', CACHE_TEMPORARY);

    // XXX: This Drupal variable should be deprecated.
    variable_set('islandora_solr_dismax_allowed', $dismax);

    return $dismax;
  }
  else {
    return $cache->data;
  }
}

/**
 * Implements hook_islandora_basic_collection_query_backends().
 */
function islandora_solr_islandora_basic_collection_query_backends() {
  $module_path = drupal_get_path('module', 'islandora_solr');
  return array(
    'islandora_solr_query_backend' => array(
      'title' => t('Solr'),
      'callable' => 'islandora_solr_islandora_basic_collection_backend_callable',
      'file' => "$module_path/includes/utilities.inc",
    ),
  );
}

/**
 * Implements hook_islandora_compound_object_query_backends().
 */
function islandora_solr_islandora_compound_object_query_backends() {
  $module_path = drupal_get_path('module', 'islandora_solr');
  return array(
    'islandora_solr_compound_query_backend' => array(
      'title' => t('SOLR - Does a Solr query with filters. Configure fields on the <a href="@solr">Solr Backend</a> tab.',
        array('@solr' => url('admin/islandora/solution_pack_config/compound_object/solr'))
      ),
      'callable' => 'islandora_solr_compound_object_query',
      'file' => "$module_path/includes/compound_backend.inc",
    ),
  );
}

/**
 * Implements hook_islandora_object_purged().
 */
function islandora_solr_islandora_object_purged($pid) {
  // XXX: Optional ability to have the system remove the object from the solr
  // index.  Useful for pages that may rely on a solr query for displaying data
  // and require the index update to be instantaneous so that the object is not
  // included in any query results immediately after a purge.
  if (variable_get('islandora_solr_force_update_index_after_object_purge', 0) == 1) {
    $options = array(
      'method' => 'POST',
      'data' => "<update><delete><id>{$pid}</id></delete><commit/></update>",
      'headers' => array('Content-Type' => 'text/xml; charset=UTF-8'),
    );
    $response = drupal_http_request(variable_get('islandora_solr_url', 'localhost:8080/solr') . '/update', $options);
  }
}

/**
 * Implements hook_islandora_basic_collection_build_manage_object().
 */
function islandora_solr_islandora_basic_collection_build_manage_object($form_state, $object) {
  if (variable_get('islandora_solr_individual_collection_sorting', FALSE)) {
    module_load_include('inc', 'islandora_solr', 'includes/collection_sort.form');
    $form_state['manage_collection_object']['manage_collection_solr_sort'] = array(
      '#id' => 'manage-collection-solr-sort',
      '#group' => 'manage_collection_solr_sort',
      '#access' => TRUE,
      '#type' => 'fieldset',
      '#title' => t('Set Solr Sort String'),
      'form' => drupal_get_form('islandora_solr_manage_collection_sort_form', $object),
    );
    return $form_state;
  }
}

/**
 * Implements hook_form_islandora_basic_collection_admin_alter().
 */
function islandora_solr_form_islandora_basic_collection_admin_alter(&$form, &$form_state, $form_id) {
  $states = array(
    'visible' => array(
      ':input[name="islandora_basic_collection_display_backend"]' => array('value' => 'islandora_solr_query_backend'),
    ),
  );
  $form['display_generation_fieldset']['islandora_collection_display']['islandora_solr_collection_sort'] = array(
    '#type' => 'textfield',
    '#title' => t('Sort field for collection query'),
    '#size' => 100,
    '#description' => t('One or more non-multivalued Solr fields to sort by when using the Solr collection query backend (by convention, multivalued fields have names that contain "_m" plus another letter at the end of their Solr names). Add " asc" or " desc" after each fieldname. If this setting is empty, the Solr default query sort will be used.'),
    '#default_value' => variable_get('islandora_solr_collection_sort', ''),
    '#states' => $states,
  );
  $form['display_generation_fieldset']['islandora_collection_display']['islandora_solr_individual_collection_sorting'] = array(
    '#type' => 'checkbox',
    '#title' => t('Allow individual sort strings per-collection'),
    '#description' => t('Allows per-collection sort strings to be configured. These sort strings can be set on the collection configuration page for individual collection objects.'),
    '#default_value' => variable_get('islandora_solr_individual_collection_sorting', FALSE),
    '#states' => $states,
  );
  $form['display_generation_fieldset']['islandora_collection_display']['islandora_solr_collection_sort_block_override'] = array(
    '#type' => 'checkbox',
    '#title' => t('Allow Solr sort block to override collection sort'),
    '#description' => t('Allows Solr sort block to override collection and default collection sort settings.'),
    '#default_value' => variable_get('islandora_solr_collection_sort_block_override', FALSE),
    '#states' => $states,
  );
  $form['display_generation_fieldset']['islandora_collection_display']['islandora_solr_collection_result_limit_block_override'] = array(
    '#type' => 'checkbox',
    '#title' => t('Allow Solr result limit block to override collection limit'),
    '#description' => t('Allows Solr result limit block to override the default collection limit.'),
    '#default_value' => variable_get('islandora_solr_collection_result_limit_block_override', FALSE),
    '#states' => $states,
  );
}

/**
 * Implements hook_islandora_breadcrumbs_backends().
 */
function islandora_solr_islandora_breadcrumbs_backends() {
  $module_path = drupal_get_path('module', 'islandora_solr');
  return array(
    ISLANDORA_SOLR_BREADCRUMB_BACKEND => array(
      'title' => t('Islandora Solr'),
      'callable' => 'islandora_solr_islandora_breadcrumbs_backends_callable',
      'file' => "$module_path/includes/breadcrumbs.inc",
    ),
  );
}

/**
 * Implements hook_preprocess().
 */
function islandora_solr_preprocess_islandora_objects_subset(&$variables) {
  $backend = variable_get('islandora_basic_collection_display_backend', ISLANDORA_BASIC_COLLECTION_LEGACY_BACKEND);
  if ($backend == 'islandora_solr_query_backend') {
    // Set the collection pager limit based on correct page size.
    global $_islandora_solr_queryclass;
    $variables['limit'] = $_islandora_solr_queryclass->solrLimit;
  }
}

/**
 * Make nice text for screen and log the exception to watchdog.
 *
 * @param \Exception $e
 *   The exception.
 */
function islandora_solr_technical_difficulties(Exception $e) {
  // Only report the error once per screen.
  $islandora_solr_error_reported = &drupal_static(__FUNCTION__, FALSE);

  if ($islandora_solr_error_reported !== TRUE) {
    drupal_set_message(t("@message", array(
      '@message' => variable_get('islandora_solr_technical_difficulties_message', ISLANDORA_SOLR_DIFFICULTIES_MESSAGE)
    )), 'warning');
    watchdog("islandora_solr", "Received exception @code: @message\nLine: @line in file: @file", array(
      '@code' => $e->getCode(),
      '@message' => $e->getMessage(),
      '@file' => $e->getFile(),
      '@line' => $e->getLine(),
    ), WATCHDOG_ERROR);
    $islandora_solr_error_reported = TRUE;
  }
}