fix: Deferred credential loading until emulator URL is determined

hiranya911 · hiranya911 · commit a8259acc2fce · 2020-12-09T13:04:42.000-08:00
diff --git a/firebase_admin/db.py b/firebase_admin/db.py
@@ -806,15 +806,17 @@ def get_client(self, db_url=None):
                 'Invalid database URL: "{0}". Database URL must be a wellformed '
                 'URL string.'.format(db_url))
 
-        base_url = 'https://{0}'.format(parsed_url.netloc)
-        params = {}
-        credential = self._credential.get_credential()
-
         emulator_config = self._get_emulator_config(parsed_url)
         if emulator_config:
-            base_url = emulator_config.base_url
-            params['ns'] = emulator_config.namespace
             credential = _EmulatorAdminCredentials()
+            base_url = emulator_config.base_url
+            params = {'ns': emulator_config.namespace}
+        else:
+            # Defer credential lookup until we are certain it's going to be prod connection.
+            credential = self._credential.get_credential()
+            base_url = 'https://{0}'.format(parsed_url.netloc)
+            params = {}
+
 
         if self._auth_override:
             params['auth_variable_override'] = self._auth_override
diff --git a/tests/test_db.py b/tests/test_db.py
@@ -729,6 +729,10 @@ def test_parse_db_url(self, url, emulator_host, expected_base_url, expected_name
             ref = db.reference()
             assert ref._client._base_url == expected_base_url
             assert ref._client.params.get('ns') == expected_namespace
+            if expected_base_url.startswith('http://localhost'):
+                assert isinstance(ref._client.credential, db._EmulatorAdminCredentials)
+            else:
+                assert isinstance(ref._client.credential, testutils.MockGoogleCredential)
         finally:
             if _EMULATOR_HOST_ENV_VAR in os.environ:
                 del os.environ[_EMULATOR_HOST_ENV_VAR]
