similar.module in Similar Entries 7.2

Module that shows a block listing similar entries. NOTE: Uses MySQL's FULLTEXT indexing for MyISAM tables.

@author David Kent Norman http://deekayen.net/ @author Arnab Nandi http://arnab.org/ @author Jordan Halterman [e-mail]

File

similar.module

<?php

/**
 * @file
 * Module that shows a block listing similar entries.
 * NOTE: Uses MySQL's FULLTEXT indexing for MyISAM tables.
 *
 * @author David Kent Norman http://deekayen.net/
 * @author Arnab Nandi http://arnab.org/
 * @author Jordan Halterman [e-mail]
 */
define('SIMILAR_INDICES', 'similar_indices');

/**
 * Implements hook_help().
 */
function similar_help($path, $arg) {
  switch ($path) {
    case 'admin/help#similar':
      return '<p>' . t('Lists the most similar nodes to the current node.') . '</p>';
  }
}

/**
 * Implements hook_views_api().
 */
function similar_views_api() {
  return array(
    'api' => 2,
    'path' => drupal_get_path('module', 'similar') . '/views',
  );
}

/**
 * Implements hook_cron().
 */
function similar_cron() {
  similar_reset_indices();
}

/**
 * Clears all Similar Entries indices.
 */
function similar_reset_indices() {
  $indices = similar_get_indices();
  if (!empty($indices)) {
    foreach ($indices as $field => $info) {
      if (isset($info['table']) && isset($info['index'])) {
        if (db_table_exists($info['table']) && db_index_exists($info['table'], $info['index'])) {
          db_drop_index($info['table'], $info['index']);
        }
      }
    }
  }
  variable_del(SIMILAR_INDICES);
  similar_index_fields();
}

/**
 * Indexes fields defined by Field module.
 *
 * Loop through each field and get field information about text
 * fields before passing data to the indexing function.
 */
function similar_index_fields() {
  if (module_exists('field')) {

    // Get all text columns defined for fields in the database.
    foreach (field_info_fields() as $field => $info) {
      if ($info['type'] == 'text' || $info['type'] == 'text_long') {
        $table = key($info['storage']['details']['sql'][FIELD_LOAD_CURRENT]);
        $column = $info['storage']['details']['sql'][FIELD_LOAD_CURRENT][$table]['value'];
        similar_index($field, $table, $column, array(
          'label' => $info['field_name'],
        ));
      }
    }
  }
}

/**
 * Adds FULLTEXT index to a single field in the database.
 *
 * @param string $field
 *   The machine-name of the field being indexed.
 * @param string $table
 *   The table that contains the field to be indexed.
 * @param string $column
 *   The name of the column to index.
 * @param array $info
 *   An optional array of information to store in Similar Entries settings.
 *
 * @return bool
 *   FALSE if the index already exists or the field does not exist.
 *   TRUE otherwise.
 */
function similar_index($field, $table, $column, $info = array()) {

  // Return FALSE if the field doesn't exist.
  $index = "similar_{$field}";
  if (!db_table_exists($table) || !db_field_exists($table, $column)) {
    return FALSE;
  }
  if (!db_index_exists($table, $index)) {
    db_query("ALTER TABLE {" . $table . "} ENGINE = MYISAM");
    db_query("ALTER TABLE {" . $table . "} ADD FULLTEXT `{$index}` (`{$column}`)");
  }

  // Add data to the info array for storage in similar indices variable.
  $info += array(
    'index' => $index,
  );
  return _similar_save_index($field, $table, $column, $info);
}

/**
 * Saves an index.
 *
 * @param string $field
 *   The machine-name of the field being indexed.
 * @param string $table
 *   The table to which the indexed field belongs.
 * @param string $column
 *   The indexed table column.
 * @param array $info
 *   Information to save about the indexed field.
 *   - table: The table name.
 *   - field: The field name.
 *   - index: The index name.
 *   - label: The human-readable field label.
 *
 * @return bool
 *   A boolean value indicating whether the index was saved.
 */
function _similar_save_index($field, $table, $column, $info) {

  // Return FALSE if the index name is not set in index info.
  if (!isset($info['index'])) {
    return FALSE;
  }
  $info += array(
    'table' => $table,
    'column' => $column,
  );
  $indices = variable_get(SIMILAR_INDICES);
  $indices[$field] = $info;
  variable_set(SIMILAR_INDICES, $indices);
  return TRUE;
}

/**
 * Returns data about what fields are currently indexed.
 *
 * Indexed tables are fields are stored in a Drupal variable. Something
 * to do is look into ways to reset the variable upon reasonable events
 * like a field module install/uninstall or a cache clearance.
 *
 * @param string|null $field
 *   An optional string identifying a specific field's index info to return.
 *
 * @return array|false
 *   An array of sub-arrays where the key is a table name and the value
 *   is an array of fields which are currently indexed in the table.
 *   Returns FALSE if the requested field index does not exist.
 */
function similar_get_indices($field = NULL) {
  $indices =& drupal_static(__FUNCTION__);
  if (!isset($indices)) {
    $indices = variable_get(SIMILAR_INDICES, array());
  }
  return $field === NULL ? $indices : (isset($indices[$field]) ? $indices[$field] : FALSE);
}

Functions

Name	Description
similar_cron	Implements hook_cron().
similar_get_indices	Returns data about what fields are currently indexed.
similar_help	Implements hook_help().
similar_index	Adds FULLTEXT index to a single field in the database.
similar_index_fields	Indexes fields defined by Field module.
similar_reset_indices	Clears all Similar Entries indices.
similar_views_api	Implements hook_views_api().
_similar_save_index	Saves an index.

Constants

Name	Description
SIMILAR_INDICES	@file Module that shows a block listing similar entries. NOTE: Uses MySQL's FULLTEXT indexing for MyISAM tables.