fix: improve json serialization

langfuse/serializer.py

@@ -39,4 +39,11 @@ def default(self, obj: Any):
         if isinstance(obj, (dict, list, str, int, float, type(None))):
             return obj
 
-        return JSONEncoder.default(self, obj)
+        if hasattr(obj, "__slots__"):
+            return self.default(
+                {slot: getattr(obj, slot, None) for slot in obj.__slots__}
+            )
+        elif hasattr(obj, "__dict__"):
+            return self.default(vars(obj))
+        else:
+            return JSONEncoder.default(self, obj)

pyproject.toml

@@ -39,6 +39,7 @@ cohere = "^4.46"
 langchain-google-vertexai = "^0.0.5"
 langchain-openai = "^0.0.5"
 dashscope = "^1.14.1"
+pymongo = "^4.6.1"
 
 [tool.poetry.extras]
 langchain = ["langchain"]

tests/test_json.py

@@ -5,6 +5,7 @@
 from datetime import datetime, timezone, date
 from unittest.mock import patch
 import uuid
+from bson import ObjectId
 
 import pytest
 from langchain.schema.messages import HumanMessage
@@ -123,3 +124,11 @@ def test_data_uuid():
     result = json.dumps(test_id, cls=EventSerializer)
 
     assert result == f'"{str(test_id)}"'
+
+
+def test_mongo_cursor():
+    test_id = ObjectId("5f3e3e3e3e3e3e3e3e3e3e3e")
+
+    result = json.dumps(test_id, cls=EventSerializer)
+
+    assert result == '{"__id": null}'