Solr Geospatial Search

Solr Geospatial Search

<?php

/**
 * Implementation of hook_form_FORM_ID_alter().
 *
 * @param $form
 * @param $form_state
 */
function searchtraining_location_form_apachesolr_search_custom_page_search_form_alter(&$form, $form_state) {
  // Get the element so we can tell autocomplete it needs to alter that so it
  // adds the Javascript
  $element = &$form['basic']['keys'];
  apachesolr_autocomplete_do_alter($element);
}

/**
 * Implement of hook_apachesolr_query_prepare()
 *
 * Prepare the query by adding parameters, sorts, etc.
 *
 * This hook is invoked before the query is cached. The cached query is used
 * after the search such as for building facet and sort blocks, so parameters
 * added during this hook may be visible to end users.
 *
 * This is otherwise the same as HOOKapachesolrquery_alter(), but runs before
 * it.
 *
 * @param DrupalSolrQueryInterface $query
 *  An object implementing DrupalSolrQueryInterface. No need for &.
 */
function searchtraining_location_apachesolr_query_prepare(DrupalSolrQueryInterface &$query) {
  // http://wiki.apache.org/solr/CommonQueryParameters#q
  // Get the search query.
  $address = $query->getParam('q');
  if (!empty($address)) {
    // Geocode an address
    $addressmd5 = md5($address);
    // caching strategy for the location hash versus coordinates
    $coordinates_cache = cache_get('searchtraining_location:address:' . $addressmd5);
    if (!empty($coordinates_cache)) {
      $coordinates = $coordinates_cache->data;
    }
    else {
      // Geocoder: https://drupal.org/project/geocoder
      // Transforms text to coordinates using Google's API.
      $point = geocoder('google',$address);
      if (!empty($point)) {
        // Geocoder found something, set it to the cache and let's use it.
        $geoJSON = $point->out('json');
        $coordinates = json_decode($geoJSON);
        cache_set('searchtraining_location:address:' . $addressmd5, $coordinates);
      }
    }
  }

  if (isset($coordinates) && !empty($coordinates->coordinates)) {
    // http://wiki.apache.org/solr/DisMaxQParserPlugin#bq.28BoostQuery.29
    // Boost on the distance
    $query->addParam('bq', '{!func}geodist()');
    $query->addParam('sfield', 'locs_field_location');
    // Solr expect the order to be different.
    // https://wiki.apache.org/solr/SpatialSearch
    // The field we want to use to compare our coordinates with is the location
    // field added by apachesolr_location. The pt (point) we want to compare it
    // with is the geocoder value we got from google and the distance is within
    // a 100 kilometers of that coordinate (the geocoder coordinate).
    $query->addParam('pt', $coordinates->coordinates[1] . ',' . $coordinates->coordinates[0]);
    $query->addParam('d', 100);

    // http://wiki.apache.org/solr/DisMaxQParserPlugin#qf.28QueryFields.29
    $query->addParam('qf', 'locs_field_location');
    // Sorting on score, score is influenced by the location distance as a
    // boost.
    $query->setSolrsort('score', 'desc');

    // Setting our Query parser to edismax
    // http://wiki.apache.org/solr/ExtendedDisMax
    $query->addParam('defType', 'edismax');
    // http://wiki.apache.org/solr/ExtendedDisMax#boost.28BoostFunction.2C_multiplicative.29
    // We're going to calculate the distance and give the boost a function so
    // that the closer the distance, the higher the boost
    $query->addParam('boost', 'recip(geodist(),2,200,20)');
    // http://wiki.apache.org/solr/CommonQueryParameters#fl
    // We want to have the field_location field back in our results (fl => fields)
    $query->addParam('fl', 'locs_field_location');
    // Since we want also results to return that do not have the location set
    // we set the search to OR. Eg. Dublin OR 123,123 (Dublin)
    $query2 = new SolrFilterSubQuery('OR');
    $query2->addFilter('content', $address);
    $query2->addFilter('_query_', "\"{!geofilt}\"");
    $query->addFilterSubQuery($query2);
  }
}

/**
 * Add some theming goodness to our results.
 *
 * Converting two coordinate sets to a distance using location functions.
 *
 * @see http://api.drupalize.me/api/drupal/function/locationdistancebetween/7
 *
 * @param array $results
 * @param DrupalSolrQueryInterface $query
 */
function searchtraining_location_apachesolr_process_results(&$results, DrupalSolrQueryInterface $query) {
  $sfield = $query->getParam('sfield');

  if (isset($sfield[0]) && $sfield[0] == 'locs_field_location') {
    foreach ($results as &$result) {
      $coordinates = $query->getParam('pt');
      $result_coordinates = $result['fields']['locs_field_location'];
      if (!empty($coordinates[0]) && $result_coordinates != '0.000000,0.000000') {
        $request_coordinates = explode(',', $coordinates[0]);
        $result_coordinates = explode(',', $result_coordinates);
        $request_coordinates['lat'] = $request_coordinates[0];
        $request_coordinates['lon'] = $request_coordinates[1];
        if (isset($result_coordinates[0]) && isset($result_coordinates[1])) {
          $result_coordinates['lat'] = $result_coordinates[0];
          $result_coordinates['lon'] = $result_coordinates[1];
          $distance = location_distance_between($request_coordinates, $result_coordinates, 'km');
          $t_args = array(
            '!scalar' => $distance['scalar'],
            '!unit' => $distance['distance_unit'],
          );
          $result['snippet'] =  $result['snippet'] . '<p class="location">';
          $result['snippet'] .= t('!scalar !unit from requested destination', $t_args);
          $result['snippet'] .= '</p></br>';
        }
      }
    }
  }
}