api.py

# filepath: c:\Users\Mohanad Hafez\Desktop\projects\ksu\api.py
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
from graph.chatbot_graph import build_graph

# Initialize FastAPI app and chatbot graph
app = FastAPI()
chatbot_graph = build_graph()

# Enable CORS
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],  # Replace "*" with specific origins in production
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Define the request schema
class ChatRequest(BaseModel):
    state: dict
    user_message: str

import logging

# Configure logging
#logging.basicConfig(level=logging.DEBUG)

@app.post("/chat")
def chat(request: ChatRequest):
    #try:
    # Ensure the state has a "messages" key
    if "messages" not in request.state:
        request.state["messages"] = []

    # Add the user's message to the state
    request.state["messages"].append({"role": "user", "content": request.user_message})

    # Process the state through the chatbot graph using the .stream() method
    events = chatbot_graph.stream(request.state, stream_mode="values")

    # Capture only the final assistant message
    last_msg = None
    for step in events:
        last_msg = step["messages"][-1]

    if last_msg:
        # Add the assistant's response back into the state
        request.state["messages"].append({"role": "assistant", "content": last_msg.content})

        # Return the assistant's response
        bot_message = last_msg.content
        return {"bot_message": bot_message, "state": request.state}
    else:
        raise ValueError("No response generated by the chatbot.")
    # except Exception as e:
    #     logging.exception("An error occurred while processing the chat request.")
    #     raise HTTPException(status_code=500, detail=str(e))