fix: serialize array output and logs (langflow-ai#3040)

* refactor: improve recursive serialization function

Refactor the `recursive_serialize_or_str` function in the `schema.py` file to improve its readability and maintainability. The function now uses a try-except block to handle exceptions and returns a string representation of the object if an exception occurs. This ensures that the function always returns a string, preventing any unexpected errors. Additionally, the function now includes additional checks for different object types, such as dictionaries, lists, and instances of `BaseModel`. These checks ensure that the function correctly serializes complex objects and avoids any potential issues. Overall, this refactoring improves the code quality and reliability of the `recursive_serialize_or_str` function.

* feat(artifact.py): add support for recursive serialization of items in ARRAY artifact type to ensure consistent data handling

* feat(schema.py): add support for serializing arrays in build_output_logs function to handle LogType.ARRAY case

(cherry picked from commit 4e9367b)

src/backend/base/langflow/custom/custom_component/component.py

@@ -1,5 +1,5 @@
 import inspect
-from typing import Any, AsyncIterator, Callable, ClassVar, Generator, Iterator, List, Optional, Union
+from typing import Any, Callable, ClassVar, List, Optional, Union
 from uuid import UUID
 
 import yaml
@@ -15,26 +15,6 @@
 from .custom_component import CustomComponent
 
 
-def recursive_serialize_or_str(obj):
-    try:
-        if isinstance(obj, dict):
-            return {k: recursive_serialize_or_str(v) for k, v in obj.items()}
-        elif isinstance(obj, list):
-            return [recursive_serialize_or_str(v) for v in obj]
-        elif isinstance(obj, BaseModel):
-            return {k: recursive_serialize_or_str(v) for k, v in obj.model_dump().items()}
-        elif isinstance(obj, (AsyncIterator, Generator, Iterator)):
-            # contain memory addresses
-            # without consuming the iterator
-            # return list(obj) consumes the iterator
-            # return f"{obj}" this generates '<generator object BaseChatModel.stream at 0x33e9ec770>'
-            # it is not useful
-            return "Unconsumed Stream"
-        return str(obj)
-    except Exception:
-        return str(obj)
-
-
 class Component(CustomComponent):
     inputs: List[InputTypes] = []
     outputs: List[Output] = []

src/backend/base/langflow/schema/artifact.py

@@ -6,6 +6,7 @@
 
 from langflow.schema import Data
 from langflow.schema.message import Message
+from langflow.schema.schema import recursive_serialize_or_str
 
 
 class ArtifactType(str, Enum):
@@ -52,6 +53,16 @@ def get_artifact_type(value, build_result=None) -> str:
 def post_process_raw(raw, artifact_type: str):
     if artifact_type == ArtifactType.STREAM.value:
         raw = ""
+    elif artifact_type == ArtifactType.ARRAY.value:
+        _raw = []
+        for item in raw:
+            if hasattr(item, "dict"):
+                _raw.append(recursive_serialize_or_str(item))
+            elif hasattr(item, "model_dump"):
+                _raw.append(recursive_serialize_or_str(item))
+            else:
+                _raw.append(str(item))
+        raw = _raw
     elif artifact_type == ArtifactType.UNKNOWN.value and raw is not None:
         if isinstance(raw, (BaseModel, dict)):
             try:

src/backend/base/langflow/schema/schema.py

@@ -1,5 +1,5 @@
 from enum import Enum
-from typing import Generator, Literal, Union
+from typing import AsyncIterator, Generator, Iterator, Literal, Union
 
 from pydantic import BaseModel
 from typing_extensions import TypedDict
@@ -104,7 +104,42 @@ def build_output_logs(vertex, result) -> dict:
 
             case LogType.UNKNOWN:
                 message = ""
+
+            case LogType.ARRAY:
+                message = [recursive_serialize_or_str(item) for item in message]
         name = output.get("name", f"output_{index}")
         outputs |= {name: OutputValue(message=message, type=_type).model_dump()}
 
     return outputs
+
+
+def recursive_serialize_or_str(obj):
+    try:
+        if isinstance(obj, dict):
+            return {k: recursive_serialize_or_str(v) for k, v in obj.items()}
+        elif isinstance(obj, list):
+            return [recursive_serialize_or_str(v) for v in obj]
+        elif isinstance(obj, BaseModel):
+            if hasattr(obj, "model_dump"):
+                obj_dict = obj.model_dump()
+            elif hasattr(obj, "dict"):
+                obj_dict = obj.dict()  # type: ignore
+            return {k: recursive_serialize_or_str(v) for k, v in obj_dict.items()}
+
+        elif isinstance(obj, (AsyncIterator, Generator, Iterator)):
+            # contain memory addresses
+            # without consuming the iterator
+            # return list(obj) consumes the iterator
+            # return f"{obj}" this generates '<generator object BaseChatModel.stream at 0x33e9ec770>'
+            # it is not useful
+            return "Unconsumed Stream"
+        elif hasattr(obj, "dict"):
+            return {k: recursive_serialize_or_str(v) for k, v in obj.dict().items()}
+        elif hasattr(obj, "model_dump"):
+            return {k: recursive_serialize_or_str(v) for k, v in obj.model_dump().items()}
+        elif issubclass(obj, BaseModel):
+            # This a type BaseModel and not an instance of it
+            return repr(obj)
+        return str(obj)
+    except Exception:
+        return str(obj)