Drupal code: Exclude some content types from node search

exclude-content-from-search.php

<?php
/**
 * Implements of hook_query_node_access_alter().
 * Exclude some content types from node search
 * Ne pas prendre en compte certains types de contenu dans la recherche
 */
function mymodule_query_node_access_alter(QueryAlterableInterface $query) {
  global $user;

  // No exclude for super admin
  if ($user->uid == 1) {
    return;
  }
  $search = FALSE;
  $node = FALSE;
  foreach ($query->getTables() as $alias => $table) {
    if ($table['table'] == 'search_index') {
      $search = $alias;
    }
    elseif ($table['table'] == 'node') {
      $node = $alias;
    }
  }

  if ($node && $search) {

    $excluded_content_types = array('contenttype1', 'contenttype2', 'contenttype3');

    // A core bug results in a DB error if we use the following: Ref: #1210072
    $query->condition($node . '.type', array($excluded_content_types), 'NOT IN');

  }
}