Drupal Snippets

delete_referencing_nodes.php

/*
  searches all nodes (of all nodetypes) that reference <code>target_nid</code> and deletes them
  dependencies: Entity, EntityReference
 */

$conditions = array( 'type' => 'entityreference' );
$include_additional = array( 'include_inactive' => TRUE );
$fields = field_read_fields( $conditions, $include_additional );
foreach( $fields as $field ){
    $query = new EntityFieldQuery();
    $results = $query
        ->entityCondition( 'entity_type', 'node' )
        ->fieldCondition( $field, 'target_id', $target_nid )
        ->execute();
    if( array_key_exists( 'node', $results ) ){
        $nids = array_keys( $results[ 'node' ] );
        node_delete_multiple( $nids );
    }
}

list_enabled_modules_drupal.php

//on source drupal installation
drush pm-list --no-core --pipe --status=enabled --type=module > dependencies.txt

//move dependencies.txt to target installation
drush en `cat dependencies.txt` --yes

retrieve_all_nodes_with_value_or_none_at_all_in_drupal.php

/*
return all nodes for a nodetype 'qux_type' that have a value of 'Bar' for a field 'field_foo' OR no value at all.
*/

$query = db_select( 'node', 'n' );
$query->leftJoin( 'field_data_field_foo', 'foo', 'n.nid=foo.entity_id' );
$result = $query->fields( 'foo', array( 'field_foo_value' ) )
    ->fields( 'n', array( 'nid' ) )
    ->condition( 'n.type', 'qux_type' )
    ->where( "foo.field_foo_value='Bar' OR (foo.field_foo_value IS NULL)" )
    ->execute()
    ->fetchAll();

/*
N.B.: the expression on the right of the OR should use the IS comparison operator, _not_ "=", 
otherwise it will only return the nodes that have a "NULL" value for that field.
*/

suggest_templates_by_path_alias.php

function <themename?_preprocess_page(&$variables, $hook) {
    /*
     * allows for defining templates by alias
     * see http://cheekymonkeymedia.ca/blog/gene-bernier/how-create-page-tpl-suggestions-based-path-alias-drupal-7
     */
    
    // Get the alias for the page being viewed
    $alias = drupal_get_path_alias($_GET['q']);
    if ($alias != $_GET['q']) {
        $template_filename = 'page';

           //Break it down for each piece of the alias path
            foreach (explode('/', $alias) as $path_part) {
            $template_filename = $template_filename . '__' . $path_part;
            $variables['theme_hook_suggestions'][] = $template_filename;
        }
    }
}