gdz_ukraine/app/middlewares/throttling.py

import asyncio

from aiogram import Dispatcher, types
from aiogram.dispatcher import DEFAULT_RATE_LIMIT
from aiogram.dispatcher.handler import CancelHandler, current_handler
from aiogram.dispatcher.middlewares import BaseMiddleware
from aiogram.utils.exceptions import Throttled


class ThrottlingMiddleware(BaseMiddleware):
    """
    Simple middleware
    """

    def __init__(self, limit=DEFAULT_RATE_LIMIT, key_prefix="antiflood_"):
        self.rate_limit = limit
        self.prefix = key_prefix
        super(ThrottlingMiddleware, self).__init__()

    async def on_process_message(self, message: types.Message, data: dict):
        """
        This handler is called when dispatcher receives a message

        :param message:
        """
        # Get current handler
        handler = current_handler.get()

        # Get dispatcher from context
        dispatcher = Dispatcher.get_current()
        # If handler was configured, get rate limit and key from handler
        if handler:
            limit = getattr(handler, "throttling_rate_limit", self.rate_limit)
            key = getattr(
                handler, "throttling_key", f"{self.prefix}_{handler.__name__}"
            )
        else:
            limit = self.rate_limit
            key = f"{self.prefix}_message"

        # Use Dispatcher.throttle method.
        try:
            await dispatcher.throttle(key, rate=limit)
        except Throttled as t:
            # Execute action
            await self.message_throttled(message, t)

            # Cancel current handler
            raise CancelHandler()

    async def message_throttled(self, message: types.Message, throttled: Throttled):
        """
        Notify user only on first exceed and notify about unlocking only on last exceed

        :param message:
        :param throttled:
        """
        handler = current_handler.get()
        dispatcher = Dispatcher.get_current()
        if handler:
            key = getattr(
                handler, "throttling_key", f"{self.prefix}_{handler.__name__}"
            )
        else:
            key = f"{self.prefix}_message"

        # Calculate how many time is left till the block ends
        delta = throttled.rate - throttled.delta

        # Prevent flooding
        if throttled.exceeded_count <= 2:
            await message.reply("Too many requests! ")

        # Sleep.
        await asyncio.sleep(delta)

        # Check lock status
        thr = await dispatcher.check_key(key)

        # If current message is not last with current key - do not send message
        if thr.exceeded_count == throttled.exceeded_count:
            await message.reply("Unlocked.")