validator

gistfile1.php

<?php

  Validator::add('uniqueFieldForClient', function($value, $format = null, $options = array()) {
  $class = $options['class'];
  $field = $options['field'];

  $conditions = array($field => $value);
  if (isset($options['values']['id'])) {
    $conditions[] = 'id != ' . $options['values']['id'];
  }

  // TODO should I throw an exception if client_id is missing? otherwise it's
  // up to the models that use this validator to also validate for requiring
  // client_id
  $conditions['client_id'] = $options['values']['client_id'];

  echo '<pre>';
  print_r($conditions);
  echo '</pre>';

  $record = $class::find('first', array('conditions' => $conditions));

  return !(bool) $record;
});

?>