feat(api): implement PydanticModelEncoder for JSON serialization

Use `PydanticModelEncoder` for JSON serialization while persisting
node execution data.

api/core/repositories/sqlalchemy_workflow_node_execution_repository.py

@@ -19,6 +19,7 @@ from core.workflow.entities.node_execution_entities import (
 )
 from core.workflow.nodes.enums import NodeType
 from core.workflow.repository.workflow_node_execution_repository import OrderConfig, WorkflowNodeExecutionRepository
+from libs.jsonutil import PydanticModelEncoder
 from models import (
     Account,
     CreatorUserRole,
@@ -161,9 +162,11 @@ class SQLAlchemyWorkflowNodeExecutionRepository(WorkflowNodeExecutionRepository)
         db_model.node_id = domain_model.node_id
         db_model.node_type = domain_model.node_type
         db_model.title = domain_model.title
-        db_model.inputs = json.dumps(domain_model.inputs) if domain_model.inputs else None
-        db_model.process_data = json.dumps(domain_model.process_data) if domain_model.process_data else None
-        db_model.outputs = json.dumps(domain_model.outputs) if domain_model.outputs else None
+        db_model.inputs = json.dumps(domain_model.inputs, cls=PydanticModelEncoder) if domain_model.inputs else None
+        db_model.process_data = (
+            json.dumps(domain_model.process_data, cls=PydanticModelEncoder) if domain_model.process_data else None
+        )
+        db_model.outputs = json.dumps(domain_model.outputs, cls=PydanticModelEncoder) if domain_model.outputs else None
         db_model.status = domain_model.status
         db_model.error = domain_model.error
         db_model.elapsed_time = domain_model.elapsed_time

api/libs/jsonutil.py

@@ -0,0 +1,11 @@
+import json
+
+from pydantic import BaseModel
+
+
+class PydanticModelEncoder(json.JSONEncoder):
+    def default(self, o):
+        if isinstance(o, BaseModel):
+            return o.model_dump()
+        else:
+            super().default(o)