How to modify the search index?

Question

There's a search index for the Apache Solr module. However, I don't see any way to change this index. It seems that various fields and items are added to the index without rhyme or reason.

If I wanted to index a field called "keywords" how would I go about this? Do I have to use the method described in Adding Customized Fields to the Apache Solr index in Drupal?

Basically, there's a keyword field, which will have comma separated values of keywords, and I want to index this for Apache Solr search.

Answer 1

You should use hook_apachesolr_index_document_build in your custom module. This hook helps to extend basic SOLR Document object and adds custom fields for indexing.

If 'Keywords' field has machine name 'field_keywords' hook implementation may be as below

/**
 * Implements hook_apachesolr_index_document_build().
 */
function MY_MODULE_apachesolr_index_document_build(ApacheSolrDocument $document, $entity, $entity_type, $env_id) {
  if ($entity_type == 'node') {
    // Adds 'Keywords' field as a separate field to Solr index.
    $document->keywords = isset($entity->field_keywords[LANGUAGE_NONE][0]['safe_value']) ?
      $entity->field_keywords[LANGUAGE_NONE][0]['safe_value'] : '';
  }
}

Answer 2

I'm not sure if the keywords field is a reference field (term or node entity). Please update the array key from the example, I used term reference as example

$term->field_keywords[LANGUAGE_NONE][0][tid]

Please try this, in your mymodule.module:

function mymodule_apachesolr_index_document_build(ApacheSolrDocument $document, $entity, $entity_type) {
  // I think you should do a foreach here, since you are using multi-valued field.
  foreach ($entity->field_keywords[LANGUAGE_NONE] as $key => $val) {
    $tid = $val['tid'];
    // The 1st letter indicates the data type and the last letter is
    // 'm' for multi-valued.
    $document->addField('im_field_keywords', $tid);
  }
}

function mymodule_apachesolr_query_alter(DrupalSolrQueryInterface $query) {
  $query->addParam('fl', 'im_field_keywords');
}

Then, prepare the variable.

/**
 * Implements hook_apachesolr_process_results().
 */
function mymodule_apachesolr_process_results(&$results) {
  foreach ($results as $key => &$result) {
    $result['foo'] = $result['node']->im_field_keywords;
  }
}

Call this variable in you search-result.tpl.php e.g.

<?php print $result['foo']; ?>

I hope it helps.

Answer 3

Do you have the search_api module installed?

If the keyword field is already a part of your content-type bundle, you should be able to see it at /admin/config/search/search_api/index/default_node_index/fields

This page allows you to pick and choose which fields to index, and to boost the fields importance in the index.