Tiny utils module that allow you to store **any** json-able data into aiogram message and read it back (from `message.html_text`)

hidden_data.py

import json
import re
from ast import literal_eval
from urllib import parse


# Functions for read and write url params
def url_loads(url_params: str) -> dict:
    parsed = parse.parse_qs(url_params)
    # parse_qs returns a dict of lists,
    # we don't allow url duplicates (e.g. ?a=1&a=2)
    # so we take the first item from each list
    return {k: literal_eval(v[0]) for k, v in parsed.items()}


def url_dumps(params: dict) -> str:
    # we need to dump strings in extra quotes to distinguish them from other types
    # we also need to escape them to correctly parse them back
    # let's use json.dumps for that
    params = {k: json.dumps(v) if isinstance(v, str) else v for k, v in params.items()}
    return parse.urlencode(params, encoding="utf-8")


# Dumping/extracting hidden params from html text (message.html_text)
# The idea is to create a link with data encoded in the url params
# and hide it in the message text using zero-width space

# ZERO_WIDTH_SPACE = "\u3164"  # Hangul Filler
ZERO_WIDTH_SPACE = "​"  # "​"
HIDDEN_LINK_TEMPLATE = f'<a href="{{url}}">{ZERO_WIDTH_SPACE}</a>'
HIDDEN_CONTAINER = HIDDEN_LINK_TEMPLATE.format(
    url="http://t.me/x/hidden_container{params}"
)

TEMPLATE = "{hidden_params}{text}"

REGEX = TEMPLATE.format(
    hidden_params=HIDDEN_CONTAINER.format(params=r"\?(?P<hidden_params>.+?)"),
    text=r"(?P<text>.*)",
)


def parse_hidden_params(html_text: str) -> tuple[dict, str]:
    m = re.fullmatch(REGEX, html_text, re.DOTALL)
    if not m:
        raise ValueError(f"Can't parse hidden container from text: {html_text}")

    task_dict = m.groupdict()
    if task_dict.get("hidden_params") is None:
        raise ValueError(f"Can't parse hidden params from text: {html_text}")

    if task_dict.get("text") is None:
        raise ValueError(f"Can't parse text from text: {html_text}")

    return url_loads(task_dict["hidden_params"]), task_dict["text"]


def dump_hidden_params(hidden_params: dict, text: str) -> str:
    result = TEMPLATE.format(
        hidden_params=HIDDEN_CONTAINER.format(params=f"?{url_dumps(hidden_params)}"),
        text=text,
    )
    return result


if __name__ == "__main__":
    data = {
        "x": "y",
        "z": 1,
        "y": True,
        "array": [1, 2, 3, True, "1", "1", {"nested": {"even": "more"}}],
        "strange": '"enquoted" string with special characters: \t\n\r\\',
        "dict": {"a": "b", "c": ["d"]},
    }

    print("Data:", data, sep="\n", end="\n\n")

    text_with_data = dump_hidden_params(
        data, "some free form text visible in a message"
    )
    print("Text with hidden data:", text_with_data, sep="\n", end="\n\n")

    extracted_data, _ = parse_hidden_params(text_with_data)

    print("Extracted data:", extracted_data, sep="\n", end="\n\n")

    print("Data is valid:", data == extracted_data)