aiogram/examples/echo_fastapi_based_bot.py

from fastapi_utils.inferring_router import InferringRouter
from fastapi import FastAPI, status, HTTPException
from aiogram import Bot, Dispatcher, types
from fastapi_utils.cbv import cbv
import logging
import asyncio


API_TOKEN = "<TOKEN>"
logging.basicConfig(level=logging.DEBUG)

class AsyncioBot:

    # Initialize bot and dispatcher
    def __init__(self) -> None:
        self.bot = Bot(token=API_TOKEN)
        self.dp = Dispatcher(self.bot)

        self.dp.register_message_handler(self.on_message)

    async def on_message(self, message: types.Message):
        print(message.get_command())
        await message.answer(f"Asnwer: {message.text}")

    async def run(self):
        # await self.dp.start_polling() # will be blocking main :on_start: FastAPI event
        asyncio.create_task(self.dp.start_polling())

    async def close(self):
        bot = self.bot.get_session()
        bot.close()


app = FastAPI()
bot = AsyncioBot()
router = InferringRouter()

@cbv(router)
class MainServer:
        
    @app.on_event("startup")
    async def on_startup():
        await bot.run()

    @router.get("/echo", status_code=status.HTTP_200_OK)
    async def echo(self):
        return {
            "status": True
        }
    
    @app.on_event("shutdown")
    async def on_shutdown():
        await bot.close() # closing bot without error

app.include_router(router)