fix(rtdb): Fixed a bug in the Reference.listen() API (#418)

Author: hiranya911

firebase_admin/db.py

@@ -373,8 +373,7 @@ def listen(self, callback):
         Raises:
           FirebaseError: If an error occurs while starting the initial HTTP connection.
         """
-        session = _sseclient.KeepAuthSession(self._client.credential)
-        return self._listen_with_session(callback, session)
+        return self._listen_with_session(callback)
 
     def transaction(self, transaction_update):
         """Atomically modifies the data at this location.
@@ -463,8 +462,11 @@ def order_by_value(self):
     def _add_suffix(self, suffix='.json'):
         return self._pathurl + suffix
 
-    def _listen_with_session(self, callback, session):
+    def _listen_with_session(self, callback, session=None):
         url = self._client.base_url + self._add_suffix()
+        if not session:
+            session = self._client.create_listener_session()
+
         try:
             sse = _sseclient.SSEClient(url, session)
             return ListenerRegistration(callback, sse)
@@ -907,6 +909,7 @@ def __init__(self, credential, base_url, timeout, params=None):
         super().__init__(
             credential=credential, base_url=base_url,
             timeout=timeout, headers={'User-Agent': _USER_AGENT})
+        self.credential = credential
         self.params = params if params else {}
 
     def request(self, method, url, **kwargs):
@@ -941,6 +944,9 @@ def request(self, method, url, **kwargs):
         except requests.exceptions.RequestException as error:
             raise _Client.handle_rtdb_error(error)
 
+    def create_listener_session(self):
+        return _sseclient.KeepAuthSession(self.credential)
+
     @classmethod
     def handle_rtdb_error(cls, error):
         """Converts an error encountered while calling RTDB into a FirebaseError."""

tests/test_db.py

@@ -551,6 +551,17 @@ def callback(_):
         finally:
             testutils.cleanup_apps()
 
+    def test_listener_session(self):
+        firebase_admin.initialize_app(testutils.MockCredential(), {
+            'databaseURL' : 'https://test.firebaseio.com',
+        })
+        try:
+            ref = db.reference()
+            session = ref._client.create_listener_session()
+            assert isinstance(session, _sseclient.KeepAuthSession)
+        finally:
+            testutils.cleanup_apps()
+
     def test_single_event(self):
         self.events = []
         def callback(event):