Reply keyboard encoding bug

[Dooweed]

As far as I understood there is a clever trick being applied to transfer callback data with regular (not inline) buttons. In the aiogram_dialog.utils there is a function encode_reply_callback that encode button id to the button text itself via invisible symbols. It is quite clever solution, but so sad that it is not documented anywhere (at least I couldn't find it).

There is also a bug with this approach - when button text is too long - telegram truncates it, hence we may encounter the case where part of the encoded id is truncated, leading to the button not getting recognized.

The easiest solution will be to add this invisible payload to the beginning of the button instead of the end.

Some more problems with this approach

• It isn't documented, and some people may end up wondering why buttons are not working (like I did, until I noticed button gets truncated on less characters even though text wasn't changed, but only the id got more characters)
• To avoid id getting truncated, the user may want to cap button texts on his own, but there isn't much convenient tooling to count how many characters separator and invisible payload will occupy
• With this approach we're limiting number of charaters can be used in buttons and introduce possibility for unexpected behavior (maybe some clients won't support the characters, or will ignore them), so I'd think about switching to state-based mapping of button text to the id, at least a parameter to choose such one

[Tishka17]

I guess we can just limit the text to something like 100 symbols

[Dooweed]

I'm afraid that won't help in all the cases. Here's an example of the capped (by telegram) button text:
"Intizor Street, Мирзо Улуғбек тумани, Тоshkent, Узбекистан𝅵­⁣­⁣⁣­⁤𝅴⁡­⁡𝅸‍⁡­‍⁤⁤­⁣⁤⁢⁤𝅺⁣𝅷⁤𝅺⁤⁡⁤‍⁤⁢­𝅴⁤𝅺⁤𝅹⁤⁡­𝅺⁣⁠⁤⁣­⁢­⁢­𝅺⁤𝅹⁤⁡­𝅵⁡⁡­‍⁤𝅸⁠⁡…" and the id is "sa-ChIJCePgiUz1rjgRxu_RGv4bNJw". As you see, there are less than 100 characters in the button

[Tishka17]

Button shows less symbols then sent by click. It is ok

[Dooweed]

Won't argue about that. Does the code strip the ellipsis added by telegram? Can't find this. If not, probably this will lead to errors too.

About the case I've sent above: The handler isn't get fired for the input from buttons

[Dooweed]

I've made some demonstration bot that shows that trimming starts from 40+ symbols in text (and 10 symbols in id) and neither of the trimmed buttons work

from aiogram import Bot, Dispatcher, types
from aiogram.filters import Command
from aiogram.types import Message
from aiogram_dialog import Dialog, DialogManager, Window, StartMode, setup_dialogs
from aiogram_dialog.widgets.kbd import Select, Column
from aiogram_dialog.widgets.markup.reply_keyboard import ReplyKeyboardFactory
from aiogram_dialog.widgets.text import Format
from aiogram.fsm.state import State, StatesGroup

API_TOKEN = ""


# 1) Define FSM states
class MyStates(StatesGroup):
    SELECT_ITEM = State()


# 2) Data getter for dynamic items
async def get_dynamic_items(dialog_manager: DialogManager, **kwargs) -> dict:
    # Example: fetch items from DB or service
    return {
        "items": [
            {"id": (str(item) * 10) * item, "name": (''.join(str((i - 1) % 10) * 10 for i in range(1, item + 1)))}
            for item in range(1, 21)
        ]
    }


# 3) Handler for when a reply-button is pressed
async def on_item_chosen(
        message: types.Message,
        select: Select,
        manager: DialogManager,
        item_id: str,
        **kwargs,
):
    await message.bot.send_message(message.from_user.id, f"You selected item with ID: {item_id}")


# 4) Build the dialog
dialog = Dialog(
    Window(
        Format("Please choose an item from the list:"),
        Column(
            Select(
                Format("{item[name]}"),
                id="dynamic_select",
                items="items",
                item_id_getter=lambda x: x["id"],
                on_click=on_item_chosen,
            )
        ),
        markup_factory=ReplyKeyboardFactory(
            resize_keyboard=True,
            one_time_keyboard=True,
        ),
        getter=get_dynamic_items,
        state=MyStates.SELECT_ITEM,
    )
)

# 5) Set up and run
if __name__ == "__main__":
    bot = Bot(token=API_TOKEN)
    dp = Dispatcher()
    setup_dialogs(dp)
    dp.include_router(dialog)


    @dp.message(Command("start"))
    async def start(message: Message, dialog_manager: DialogManager):
        # Important: always set `mode=StartMode.RESET_STACK` you don't want to stack dialogs
        await dialog_manager.start(MyStates.SELECT_ITEM, mode=StartMode.RESET_STACK)


    dp.run_polling(bot)

Also these three dots may be a misleading for user, especially if nothing from visible text is actually trimmed