ownCloud Keystone Authentication

config.php

<?php

  "user_backends" => array (
    0 => array (
      "class"     => "OC_User_Keystone",
      "arguments" => array (
        0 => 'https://keystone.example.com:35357/v2.0'
      ),
    ),
  ),

keystone.php

<?php
/**
 * Copyright (c) 2015 Joe Topjian <[email protected]>
 * This file is licensed under the Affero General Public License version 3 or
 * later.
 * See the COPYING-README file.
 */

/**
 * User authentication against an OpenStack Keystone server
 *
 * @category Apps
 * @package  UserExternal
 * @author   Joe Topjian <[email protected]>
 * @license  http://www.gnu.org/licenses/agpl AGPL
 * @link     http://github.com/owncloud/apps
 */
class OC_User_Keystone extends \OCA\user_external\Base{
  private $host;

  /**
   * Create new Keystone authentication provider
   *
   * @param string  $host   Host / URL to Keystone server.
   */
  public function __construct($host) {
    $this->host=$host;
    parent::__construct($this->host);
  }

  /**
   * Check if the password is correct without logging in the user
   *
   * @param string $uid      The username
   * @param string $password The password
   *
   * @return true/false
   */
  public function checkPassword($uid, $password) {
    $client = new OpenCloud\OpenStack($this->host, array(
      'username' => $uid,
      'password' => $password,
    ));
    try {
      $json = $client->getCredentials();
      $service = $client->identityService();
      $response = $service->generateToken($json);
      $jsonBody = $response->json();
      if (isset($jsonBody['access']['token']['id'])) {
        $this->storeUser($uid);
        return $uid;
      } else {
        return false;
      }
    } catch (Exception $e) {
      OCP\Util::writeLog(
        'user_external', 'ERROR: keystone login failed for user ' . $uid,
        OCP\Util::ERROR
      );
      return false;
    }
    return false;
  }
}