From 273f452f7b40cceacdef27fd0cf16a0f875c2bf9 Mon Sep 17 00:00:00 2001
From: Gabriel Luiz Freitas Almeida <gabriel@logspace.ai>
Date: Mon, 12 Jun 2023 07:50:00 -0300
Subject: [PATCH] =?UTF-8?q?=F0=9F=94=A7=20chore(chat.py):=20add=20SSE=20su?=
 =?UTF-8?q?pport=20to=20post=5Fbuild=20endpoint=20=E2=9C=A8=20feat(chat.py?=
 =?UTF-8?q?):=20add=20SSE=20support=20to=20post=5Fbuild=20endpoint=20to=20?=
 =?UTF-8?q?stream=20build=20progress=20to=20the=20client=20The=20post=5Fbu?=
 =?UTF-8?q?ild=20endpoint=20now=20returns=20a=20StreamingResponse=20object?=
 =?UTF-8?q?=20that=20streams=20Server-Sent=20Events=20(SSE)=20to=20the=20c?=
 =?UTF-8?q?lient.=20This=20allows=20the=20client=20to=20receive=20build=20?=
 =?UTF-8?q?progress=20updates=20in=20real-time.=20The=20event=5Fstream=20f?=
 =?UTF-8?q?unction=20is=20responsible=20for=20generating=20the=20SSE=20eve?=
 =?UTF-8?q?nts=20and=20is=20called=20by=20the=20StreamingResponse=20object?=
 =?UTF-8?q?.=20The=20SSE=20events=20contain=20information=20about=20the=20?=
 =?UTF-8?q?build=20progress,=20including=20whether=20the=20build=20was=20s?=
 =?UTF-8?q?uccessful=20or=20not,=20the=20parameters=20used=20to=20build=20?=
 =?UTF-8?q?each=20node,=20and=20the=20node=20ID.=20The=20chat=5Fmanager.se?=
 =?UTF-8?q?t=5Fcache=20method=20is=20called=20to=20cache=20the=20built=20g?=
 =?UTF-8?q?raph=20object.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 src/backend/langflow/api/v1/chat.py | 39 +++++++++++++++++++++++------
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/src/backend/langflow/api/v1/chat.py b/src/backend/langflow/api/v1/chat.py
index 9619d5f30..2c085c187 100644
--- a/src/backend/langflow/api/v1/chat.py
+++ b/src/backend/langflow/api/v1/chat.py
@@ -1,3 +1,4 @@
+import json
 from fastapi import (
     APIRouter,
     HTTPException,
@@ -6,8 +7,10 @@ from fastapi import (
     WebSocketException,
     status,
 )
+from fastapi.responses import StreamingResponse
 
 from langflow.chat.manager import ChatManager
+from langflow.graph.graph.base import Graph
 from langflow.utils.logger import logger
 
 router = APIRouter()
@@ -27,12 +30,34 @@ async def websocket_endpoint(client_id: str, websocket: WebSocket):
         await websocket.close(code=status.WS_1000_NORMAL_CLOSURE, reason=str(exc))
 
 
-@router.post("/build/{client_id}")
+@router.post("/build/{client_id}", response_class=StreamingResponse)
 async def post_build(client_id: str, graph_data: dict):
     """Build langchain object from data_graph."""
-    try:
-        if chat_manager.build(client_id, graph_data.get("data")):
-            return {"message": "Build successful"}
-    except Exception as exc:
-        logger.exception(exc)
-        raise HTTPException(status_code=500, detail=str(exc)) from exc
+
+    async def event_stream(graph_data):
+        try:
+            graph_data = graph_data.get("data")
+            if not graph_data:
+                raise HTTPException(status_code=400, detail="No data provided")
+
+            logger.debug("Building langchain object")
+            graph = Graph.from_payload(graph_data)
+            for node in graph.generator_build():
+                logger.debug(f"Building node {node.name}")
+                response = json.dumps(
+                    {
+                        "valid": True,
+                        "params": str(node._built_object_repr()),
+                        "id": node.id,
+                    }
+                )
+                yield f"data: {response}\n\n"  # SSE format
+
+            chat_manager.set_cache(client_id, graph.build())
+
+        except Exception as exc:
+            logger.exception(exc)
+            error_response = json.dumps({"error": str(exc)})
+            yield f"data: {error_response}\n\n"  # SSE format
+
+    return StreamingResponse(event_stream(graph_data), media_type="text/event-stream")