chore: fix 'Object of is not JSON serializable' when use ChatAgent.save_memory() (#3179)

Co-authored-by: Wendong-Fan <133094783+Wendong-Fan@users.noreply.github.com>
Co-authored-by: Wendong-Fan <w3ndong.fan@gmail.com>

Author: fengju0213

camel/memories/records.py

@@ -70,14 +70,31 @@ def from_dict(cls, record_dict: Dict[str, Any]) -> "MemoryRecord":
         Args:
             record_dict(Dict[str, Any]): A dict generated by :meth:`to_dict`.
         """
+        from camel.types import (
+            OpenAIBackendRole,
+            RoleType,
+        )
+
         message_cls = cls._MESSAGE_TYPES[record_dict["message"]["__class__"]]
         kwargs: Dict = record_dict["message"].copy()
         kwargs.pop("__class__")
+
+        # Convert role_type string back to RoleType enum if it's a string
+        if "role_type" in kwargs and isinstance(kwargs["role_type"], str):
+            kwargs["role_type"] = RoleType(kwargs["role_type"])
+
         reconstructed_message = message_cls(**kwargs)
+
+        # Convert role_at_backend string back to OpenAIBackendRole enum if
+        # it's a string
+        role_at_backend = record_dict["role_at_backend"]
+        if isinstance(role_at_backend, str):
+            role_at_backend = OpenAIBackendRole(role_at_backend)
+
         return cls(
             uuid=UUID(record_dict["uuid"]),
             message=reconstructed_message,
-            role_at_backend=record_dict["role_at_backend"],
+            role_at_backend=role_at_backend,
             extra_info=record_dict["extra_info"],
             timestamp=record_dict["timestamp"],
             agent_id=record_dict["agent_id"],
@@ -93,7 +110,9 @@ def to_dict(self) -> Dict[str, Any]:
                 "__class__": self.message.__class__.__name__,
                 **asdict(self.message),
             },
-            "role_at_backend": self.role_at_backend,
+            "role_at_backend": self.role_at_backend.value
+            if hasattr(self.role_at_backend, "value")
+            else self.role_at_backend,
             "extra_info": self.extra_info,
             "timestamp": self.timestamp,
             "agent_id": self.agent_id,

camel/storages/key_value_storages/json.py

@@ -17,6 +17,8 @@
 from pathlib import Path
 from typing import Any, ClassVar, Dict, List, Optional
 
+from pydantic import BaseModel
+
 from camel.storages.key_value_storages import BaseKeyValueStorage
 from camel.types import (
     ModelType,
@@ -27,8 +29,13 @@
 
 
 class CamelJSONEncoder(json.JSONEncoder):
-    r"""A custom JSON encoder for serializing specifically enumerated types.
-    Ensures enumerated types can be stored in and retrieved from JSON format.
+    r"""A custom JSON encoder for serializing CAMEL-specific types.
+
+    Handles serialization of:
+    - Enumerated types (RoleType, TaskType, ModelType, OpenAIBackendRole)
+    - Pydantic BaseModel objects (from structured outputs)
+
+    Ensures these types can be stored in and retrieved from JSON format.
     """
 
     CAMEL_ENUMS: ClassVar[Dict[str, EnumMeta]] = {
@@ -39,8 +46,14 @@ class CamelJSONEncoder(json.JSONEncoder):
     }
 
     def default(self, obj) -> Any:
+        # Handle CAMEL enum types
         if type(obj) in self.CAMEL_ENUMS.values():
             return {"__enum__": str(obj)}
+
+        # Handle Pydantic BaseModel objects (e.g., from structured outputs)
+        if isinstance(obj, BaseModel):
+            return obj.model_dump()
+
         # Let the base class default method raise the TypeError
         return json.JSONEncoder.default(self, obj)