Amend index queries to use efq

Hi,
I'm using services to exchange data with a JavaClient. Now I need to retrieve a user by searching a value in a custom field that I add to the user account (in admin/config/people/accounts/fields). I did not find how to do this with the actual methods, so I create a new method "index_and_cckfield".
This is working for me, so I posted it in case that somone else need this use case.

The method "user.index_and_cckfield" take the same parameters that "user.index", plus one : an array of custom user fields and his value. For example : array ( 'field_example_name' => 'a_value') .

/**
 * 
 * Implements hook_services_resources
 * 
 */
function parcours_pedagogique_services_resources() {
    return array(
        'user' => array(
            'actions' => array (
                 'index_and_cckfield' => array(
                      //'file' => array('type' => 'inc', 'module' => 'services', 'name' => 'resources/user_resource'),
                      'callback' => '_user_resource_index_and_cckfield',
                      'access callback' => '_group_resource_access',
                      'access arguments' => array('view'),
                      'access arguments append' => TRUE,
                      'args' => array(
                        array(
                          'name' => 'page',
                          'optional' => TRUE,
                          'type' => 'int',
                          'description' => 'The zero-based index of the page to get, defaults to 0.',
                          'default value' => 0,
                          'source' => array('path' => '0'),
                        ),
                        array(
                          'name' => 'fields',
                          'optional' => TRUE,
                          'type' => 'string',
                          'description' => 'The fields to get.',
                          'default value' => '*',
                          'source' => array('path' => '0'),
                        ),
                        array(
                          'name' => 'parameters',
                          'optional' => TRUE,
                          'type' => 'array',
                          'description' => 'Parameters',
                          'default value' => array(),
                          'source' => array('path' => '0'),
                        ),
                        array(
                          'name' => 'cck_fields',
                          'optional' => TRUE,
                          'type' => 'array',
                          'description' => 'The cck field to get',
                          'default value' => array(),
                          'source' => array('path' => '0'),
                        ), 
                     ),
                 ),
             ),
         ),
        
        
      
    );
}


/**
 * 
 * This code is from the user_resources.inc file of the services module.
 * The name of the method was _user_resource_index.
 * There's just one line added (calling _services_resources_build_cck_field_query)
 * 
 * @param $page
 *   Page number of results to return (in pages of 20).
 * @param $fields
 *   The fields you want returned.
 * @param $parameters
 *   An object containing fields and values used to build a sql WHERE clause indicating
 *   what items should be deleted.
 * @param $cck_fields
 *  An object containing the name of the user fields and value (created in admin/config/people/accounts/fields)
 *  This build a INNERJOIN clause and a WHERE clause.
 *  Example of the object : array ( 'field_example_name' => 'a_value')
 * @return
 *   An array of user objects.
 *
 */
function _user_resource_index_and_cckfield($page, $fields, $parameters,  $cck_fields){ 
   $user_select = db_select('users', 't')
    ->orderBy('created', 'DESC');
   
  services_resource_build_index_query($user_select, $page, $fields, $parameters);

  _services_resources_build_cck_field_query($user_select, $page, $cck_fields);
  
  $results = $user_select->execute();

  return services_resource_build_index_list($results, 'user', 'uid');
}


/**
 * Helper function to build index queries.
 *
 * @param $query
 *   Object database query object.
 * @param $page
 *   Integer page number we are requesting.
 * @param $fields
 *   Array of the user account fields to return.
 */
function _services_resources_build_cck_field_query($query, $page, $cck_fields =array()) {
  $page_size = variable_get('services_index_page_size', 20);
  $query->range($page * $page_size, $page_size);
  
  foreach($cck_fields as $f => $val){
    $t = 'field_data_'.$f;
    //$val = $field['value'];
    $query->innerjoin($t,$f, $f.'.entity_id=t.uid');
    $query->condition($f.'.'.$f.'_value',$val);
    $query->fields($f,array($f.'_value'));
  }  
}

Hope this could be usefull ;)