Refactor PromptRunner class to use langchain_core.messages.BaseMessage

src/backend/langflow/components/chains/PromptRunner.py

@@ -1,8 +1,9 @@
-from langflow import CustomComponent
-
 from langchain.llms.base import BaseLLM
 from langchain.prompts import PromptTemplate
-from langchain.schema import Document
+from langchain_core.messages import BaseMessage
+
+from langflow import CustomComponent
+from langflow.field_typing import Text
 
 
 class PromptRunner(CustomComponent):
@@ -18,11 +19,15 @@ class PromptRunner(CustomComponent):
         "code": {"show": False},
     }
 
-    def build(self, llm: BaseLLM, prompt: PromptTemplate, inputs: dict = {}) -> Document:
+    def build(self, llm: BaseLLM, prompt: PromptTemplate, inputs: dict = {}) -> Text:
         chain = prompt | llm
         # The input is an empty dict because the prompt is already filled
-        result = chain.invoke(input=inputs)
-        if hasattr(result, "content"):
-            result = result.content
+        result_message: BaseMessage = chain.invoke(input=inputs)
+        if hasattr(result_message, "content"):
+            result: str = result_message.content
+        elif isinstance(result_message, str):
+            result = result_message
+        else:
+            result = str(result_message)
         self.repr_value = result
-        return Document(page_content=str(result))
+        return result