throw SessionNotAvailableException if session_id returns empty string

lib/private/Session/CryptoSessionData.php

@@ -24,6 +24,7 @@ namespace OC\Session;
 
 use OCP\ISession;
 use OCP\Security\ICrypto;
+use OCP\Session\Exceptions\SessionNotAvailableException;
 
 /**
  * Class CryptoSessionData
@@ -145,6 +146,7 @@ class CryptoSessionData implements \ArrayAccess, ISession {
 	 * Wrapper around session_id
 	 *
 	 * @return string
+	 * @throws SessionNotAvailableException
 	 * @since 9.1.0
 	 */
 	public function getId() {

lib/private/Session/Internal.php

@@ -26,6 +26,8 @@
 
 namespace OC\Session;
 
+use OCP\Session\Exceptions\SessionNotAvailableException;
+
 /**
  * Class Internal
  *
@@ -115,10 +117,15 @@ class Internal extends Session {
 	 * Wrapper around session_id
 	 *
 	 * @return string
+	 * @throws SessionNotAvailableException
 	 * @since 9.1.0
 	 */
 	public function getId() {
-		return @session_id();
+		$id = @session_id();
+		if ($id === '') {
+			throw new SessionNotAvailableException();
+		}
+		return $id;
 	}
 
 	/**

lib/private/Session/Memory.php

@@ -26,6 +26,9 @@
 
 namespace OC\Session;
 
+use Exception;
+use OCP\Session\Exceptions\SessionNotAvailableException;
+
 /**
  * Class Internal
  *
@@ -92,10 +95,11 @@ class Memory extends Session {
 	 * Wrapper around session_id
 	 *
 	 * @return string
+	 * @throws SessionNotAvailableException
 	 * @since 9.1.0
 	 */
 	public function getId() {
-		throw new \Exception('Memory session does not have an ID');
+		throw new SessionNotAvailableException('Memory session does not have an ID');
 	}
 
 	/**
@@ -108,11 +112,11 @@ class Memory extends Session {
 	/**
 	 * In case the session has already been locked an exception will be thrown
 	 *
-	 * @throws \Exception
+	 * @throws Exception
 	 */
 	private function validateSession() {
 		if ($this->sessionClosed) {
-			throw new \Exception('Session has been closed - no further changes to the session are allowed');
+			throw new Exception('Session has been closed - no further changes to the session are allowed');
 		}
 	}
 }

lib/public/Session/Exceptions/SessionNotAvailableException.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * @author Christoph Wurst <christoph@owncloud.com>
+ *
+ * @copyright Copyright (c) 2016, ownCloud, Inc.
+ * @license AGPL-3.0
+ *
+ * This code is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * 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, version 3,
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+namespace OCP\Session\Exceptions;
+
+use Exception;
+
+/**
+ * @since 9.1.0
+ */
+class SessionNotAvailableException extends Exception {
+	
+}

lib/public/isession.php

@@ -100,6 +100,7 @@ interface ISession {
 	 * Wrapper around session_id
 	 *
 	 * @return string
+	 * @throws SessionNotAvailableException
 	 * @since 9.1.0
 	 */
 	public function getId();

tests/lib/session/memory.php

@@ -17,7 +17,7 @@ class Memory extends Session {
 	}
 
 	/**
-	 * @expectedException \Exception
+	 * @expectedException OCP\Session\Exceptions\SessionNotAvailableException
 	 */
 	public function testThrowsExceptionOnGetId() {
 		$this->instance->getId();