🐛 fix(endpoints.py): fix predict endpoint to load flow from database instead of request

✨ feat(endpoints.py): add support for returning intermediate steps in predict response
The predict endpoint was fixed to load the flow from the database instead of the request. This ensures that the correct flow is used for prediction. Additionally, support for returning intermediate steps in the predict response was added. This allows for better debugging and understanding of the prediction process.

src/backend/langflow/api/endpoints.py

@@ -1,10 +1,11 @@
+import json
+from langflow.database.models.flow import Flow
 from langflow.utils.logger import logger
 from importlib.metadata import version
 
-from fastapi import APIRouter, File, HTTPException, UploadFile
+from fastapi import APIRouter, Depends, File, HTTPException, UploadFile
 
 from langflow.api.schemas import (
-    ExportedFlow,
     GraphData,
     PredictRequest,
     PredictResponse,
@@ -12,7 +13,9 @@ from langflow.api.schemas import (
 from langflow.interface.run import process_graph_cached
 from langflow.interface.types import build_langchain_types_dict
 from langflow.cache import cache_manager
-
+from langflow.database.base import get_session
+from sqlmodel import Session
+from sqlmodel import select
 # build router
 router = APIRouter(tags=["Base"])
 
@@ -22,14 +25,17 @@ def get_all():
     return build_langchain_types_dict()
 
 
-@router.post("/predict", response_model=PredictResponse)
-async def get_load(predict_request: PredictRequest):
+@router.post("/predict/{flow_id}", status_code=200, response_model=PredictResponse)
+async def get_load(predict_request: PredictRequest, flow_id: str, session: Session= Depends(get_session)):
+
     try:
-        exported_flow: ExportedFlow = predict_request.exported_flow
-        graph_data: GraphData = exported_flow.data
+        flow_obj = session.get(Flow, flow_id)
+        if flow_obj is None:
+            raise ValueError(f"Flow {flow_id} not found")
+        graph_data: GraphData = json.loads(flow_obj.flow)
         data = graph_data.dict()
         response = process_graph_cached(data, predict_request.message)
-        return PredictResponse(result=response.get("result", ""))
+        return PredictResponse(result=response.get("result", ""), intermediate_steps=response.get("thought", ""))
     except Exception as e:
         # Log stack trace
         logger.exception(e)

src/backend/langflow/api/schemas.py

@@ -24,13 +24,13 @@ class PredictRequest(BaseModel):
     """Predict request schema."""
 
     message: str
-    exported_flow: ExportedFlow
 
 
 class PredictResponse(BaseModel):
     """Predict response schema."""
 
     result: str
+    intermediate_steps: str = ""
 
 
 class ChatMessage(BaseModel):