3 files changed, 17 insertions, 4 deletions
diff --git a/lib/private/Session/CryptoSessionData.php b/lib/private/Session/CryptoSessionData.php
index 23731ef4560..629e6af5412 100644
--- a/lib/private/Session/CryptoSessionData.php
+++ b/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() {
diff --git a/lib/private/Session/Internal.php b/lib/private/Session/Internal.php
index 4fadb1ac801..a24aec55222 100644
--- a/lib/private/Session/Internal.php
+++ b/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;
 	}
 
 	/**
diff --git a/lib/private/Session/Memory.php b/lib/private/Session/Memory.php
index 3dba274f395..bcb1f1d950c 100644
--- a/lib/private/Session/Memory.php
+++ b/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');
 		}
 	}
 }