app_init.py

from fastapi import FastAPI, WebSocket, HTTPException, WebSocketDisconnect
from fastapi.responses import StreamingResponse, JSONResponse
from fastapi.middleware.cors import CORSMiddleware
from fastapi.staticfiles import StaticFiles
from fastapi import Request

import logging
import traceback
from config import Args
from user_queue import UserDataEventMap, UserDataEvent
import uuid
from asyncio import Event, sleep
import time
from PIL import Image
from types import SimpleNamespace
from util import pil_to_frame, is_firefox


def init_app(app: FastAPI, user_data_events: UserDataEventMap, args: Args, pipeline):
    app.add_middleware(
        CORSMiddleware,
        allow_origins=["*"],
        allow_credentials=True,
        allow_methods=["*"],
        allow_headers=["*"],
    )

    @app.websocket("/ws")
    async def websocket_endpoint(websocket: WebSocket):
        await websocket.accept()
        if args.max_queue_size > 0 and len(user_data_events) >= args.max_queue_size:
            print("Server is full")
            await websocket.send_json({"status": "error", "message": "Server is full"})
            await websocket.close()
            return

        try:
            uid = str(uuid.uuid4())
            print(f"New user connected: {uid}")
            await websocket.send_json(
                {"status": "success", "message": "Connected", "userId": uid}
            )
            user_data_events[uid] = UserDataEvent()
            await websocket.send_json(
                {"status": "start", "message": "Start Streaming", "userId": uid}
            )
            await handle_websocket_data(websocket, uid)
        except WebSocketDisconnect as e:
            logging.error(f"WebSocket Error: {e}, {uid}")
            traceback.print_exc()
        finally:
            print(f"User disconnected: {uid}")
            del user_data_events[uid]

    @app.get("/queue_size")
    async def get_queue_size():
        queue_size = len(user_data_events)
        return JSONResponse({"queue_size": queue_size})

    @app.get("/stream/{user_id}")
    async def stream(user_id: uuid.UUID, request: Request):
        uid = str(user_id)
        try:

            async def generate():
                while True:
                    data = await user_data_events[uid].wait_for_data()
                    params = data["params"]
                    image = pipeline.predict(params)
                    if image is None:
                        continue
                    frame = pil_to_frame(image)
                    yield frame
                    # https://bugs.chromium.org/p/chromium/issues/detail?id=1250396
                    if not is_firefox(request.headers["user-agent"]):
                        yield frame

            return StreamingResponse(
                generate(),
                media_type="multipart/x-mixed-replace;boundary=frame",
                headers={"Cache-Control": "no-cache"},
            )
        except Exception as e:
            logging.error(f"Streaming Error: {e}, {user_data_events}")
            traceback.print_exc()
            return HTTPException(status_code=404, detail="User not found")

    async def handle_websocket_data(websocket: WebSocket, user_id: uuid.UUID):
        uid = str(user_id)
        if uid not in user_data_events:
            return HTTPException(status_code=404, detail="User not found")
        last_time = time.time()
        try:
            while True:
                params = await websocket.receive_json()
                params = pipeline.InputParams(**params)
                info = pipeline.Info()
                params = SimpleNamespace(**params.dict())
                if info.input_mode == "image":
                    image_data = await websocket.receive_bytes()
                    pil_image = Image.open(io.BytesIO(image_data))
                    params.image = pil_image
                user_data_events[uid].update_data({"params": params})
                if args.timeout > 0 and time.time() - last_time > args.timeout:
                    await websocket.send_json(
                        {
                            "status": "timeout",
                            "message": "Your session has ended",
                            "userId": uid,
                        }
                    )
                    await websocket.close()
                    return

        except Exception as e:
            logging.error(f"Error: {e}")
            traceback.print_exc()

    # route to setup frontend
    @app.get("/settings")
    async def settings():
        info = pipeline.Info.schema()
        input_params = pipeline.InputParams.schema()
        return JSONResponse(
            {
                "info": info,
                "input_params": input_params,
                "max_queue_size": args.max_queue_size,
            }
        )

    app.mount("/", StaticFiles(directory="public", html=True), name="public")