Refactor field typing in LLMChainComponent and

related modules

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

@@ -1,7 +1,12 @@
 from langflow import CustomComponent
 from langchain.chains import LLMChain
 from typing import Optional, Union, Callable
-from langflow.field_typing import PromptTemplate, BaseLanguageModel, BaseMemory, Chain
+from langflow.field_typing import (
+    BasePromptTemplate,
+    BaseLanguageModel,
+    BaseMemory,
+    Chain,
+)
 
 
 class LLMChainComponent(CustomComponent):
@@ -18,7 +23,7 @@ class LLMChainComponent(CustomComponent):
 
     def build(
         self,
-        prompt: PromptTemplate,
+        prompt: BasePromptTemplate,
         llm: BaseLanguageModel,
         memory: Optional[BaseMemory] = None,
     ) -> Union[Chain, Callable]:

src/backend/langflow/field_typing/__init__.py

@@ -17,6 +17,8 @@
 from .constants import (
     Tool,
     PromptTemplate,
+    ChatPromptTemplate,
+    BasePromptTemplate,
     Chain,
     BaseChatMemory,
     BaseLLM,
@@ -54,4 +56,6 @@ __all__ = [
     "Document",
     "AgentExecutor",
     "Callable",
+    "BasePromptTemplate",
+    "ChatPromptTemplate",
 ]

src/backend/langflow/field_typing/constants.py

@@ -3,7 +3,7 @@ from langchain.chains.base import Chain
 from langchain.document_loaders.base import BaseLoader
 from langchain.llms.base import BaseLLM, BaseLanguageModel
 from langchain.memory.chat_memory import BaseChatMemory
-from langchain.prompts import PromptTemplate
+from langchain.prompts import PromptTemplate, ChatPromptTemplate
 from langchain.schema import BaseOutputParser, BaseRetriever, Document
 from langchain.schema.embeddings import Embeddings
 from langchain.schema.memory import BaseMemory
@@ -27,6 +27,7 @@ LANGCHAIN_BASE_TYPES = {
     "BaseLLM": BaseLLM,
     "BaseLanguageModel": BaseLanguageModel,
     "PromptTemplate": PromptTemplate,
+    "ChatPromptTemplate": ChatPromptTemplate,
     "BaseLoader": BaseLoader,
     "Document": Document,
     "TextSplitter": TextSplitter,

src/backend/langflow/interface/custom/custom_component.py

@@ -5,7 +5,7 @@ from langflow.field_typing.constants import CUSTOM_COMPONENT_SUPPORTED_TYPES
 from langflow.interface.custom.component import Component
 from langflow.interface.custom.directory_reader import DirectoryReader
 from langflow.services.getters import get_db_service
-from langflow.interface.custom.utils import extract_inner_type
+from langflow.interface.custom.utils import extract_inner_type, extract_union_types
 
 from langflow.utils import validate
 
@@ -152,9 +152,7 @@ class CustomComponent(Component):
             return [return_type] if return_type in self.return_type_valid_list else []
 
         # If the return type is a Union, then we need to parse it
-        return_type = return_type.replace("Union", "").replace("[", "").replace("]", "")
-        return_type = return_type.split(",")
-        return_type = [item.strip() for item in return_type]
+        return_type = extract_union_types(return_type)
         return [item for item in return_type if item in self.return_type_valid_list]
 
     @property

src/backend/langflow/interface/custom/utils.py

@@ -8,3 +8,14 @@ def extract_inner_type(return_type: str) -> str:
     if match := re.match(r"list\[(.*)\]", return_type, re.IGNORECASE):
         return match[1]
     return return_type
+
+
+def extract_union_types(return_type: str) -> list[str]:
+    """
+    Extracts the inner type from a type hint that is a list.
+    """
+    # If the return type is a Union, then we need to parse it
+    return_type = return_type.replace("Union", "").replace("[", "").replace("]", "")
+    return_type = return_type.split(",")
+    return_type = [item.strip() for item in return_type]
+    return return_type