how to pass variable or object to dp.message_handler decorated function?

[TonyZhang03]

I can't find an example provided by the package helpful to build a real chatbot. Can anyone here help to explain how or give an example? here is my problem. Thank you in advance.

[Olegt0rr]

If you wanna pass a function to your handler just import it and use it directly.
If you wanna apply it for some handlers, you should use a middleware.

Direct usage

def generate_text():
    return "generated text"

async def handler(message: Message):
    text = generate_text()
    await message.answer(text)

Middleware usage

Create a middleware

from aiogram.dispatcher.middlewares import BaseMiddleware
from aiogram.types import Message

class YourMiddleware(BaseMiddleware):
    async def on_pre_process_message(self, message: Message, data: dict):
        # `text` is a name of var passed to handler
        data["text"] = generate_text()

Register it via Dispatcher (on_startup)

dp.middleware.setup(YourMiddleware())

Get text data inside the handler

from aiogram.types import Message

async def handler(message: Message, text: str):
    await message.answer(text)