Get the proper UID

Some user backends (like the database backend) allow us to obtain a user
case insensitive. However the UID itself is case sensitive.

Example:
* create a user User1
* login as User1
  - This results the data/User1 folder to be created etc
* now have some code somewhere that obtains the userFolder (from
IRootFolder) but pas in 'uSER1' as uid
  - The code will check if that is a valid user. And in this case it is
  since User1 and uSER1 both map to the same user
  - However the the UID in the user object is used for the folder a new
  folder fill be create data/uSER1

With this PR this is avoided now. Since we obtain the real UID casing in
the backend before creating the user object.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

1 files changed, 44 insertions, 0 deletions

diff --git a/lib/public/User/Backend/IGetRealUIDBackend.php b/lib/public/User/Backend/IGetRealUIDBackend.php
new file mode 100644
index 00000000000..b7eb6ac43ee
--- /dev/null
+++ b/lib/public/User/Backend/IGetRealUIDBackend.php
@@ -0,0 +1,44 @@
+<?php
+declare(strict_types=1);
+/**
+ * @copyright Copyright (c) 2019, Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @author Roeland Jago Douma <roeland@famdouma.nl>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCP\User\Backend;
+
+/**
+ * @since 17.0.0
+ */
+interface IGetRealUIDBackend {
+
+	/**
+	 * Some backends accept different UIDs than what is the internal UID to be used.
+	 * For example the database backend accepts differnt cased UIDs in all the functions
+	 * but the internal UID that is to be used should be correctly cased.
+	 *
+	 * This little function makes sure that the used UID will be correct hen using the user object
+	 *
+	 * @since 17.0.0
+	 * @param string $uid
+	 * @return string
+	 */
+	public function getRealUID(string $uid): string;
+}