ass-tg

Arguments Searcher of Sophie (ASS)

The library used to parse arguments from the message.

Currently, works only with Aiogram 3.x!

See also:

• Sophie Text Formatting Utility library (STFU)

Quick example:

Let's create a handler for a tban (temporary ban) command using ASS arguments.

from ass_tg.types import UserArg, ActionTimeArg, TextArg, OptionalArg

from stfu_tg import Section, KeyValue


@dp.message(Command('tban'))  # Set a command filter
@flags.args(
    user=UserArg("User"),
    time=ActionTimeArg("Time to ban"),
    description=OptionalArg(TextArg("Reason text"))
)
async def tban_user_handler(
        msg: Message,
        user: str,
        time: timedelta,
        description: str | None
):
    # Here we used STFU's formatting, but you can use variables as you wish!
    await msg.reply(str(Section(
        KeyValue("User", user),
        KeyValue("On", time),
        KeyValue("Description", description or "No description"),
        title="Ban"
    )))

The argument parser contains inbuilt type and argument checker:

The list of arguments to use

Currently, you can see all the available arguments in the ass_tg/types/init.py file Here's the small list of which ones you can use right away:

• TextArg
• WordArg
• IntArg
• BooleanArg
• ActionTimeArg
• UsernameArg
• UserIDArg
• UserMentionArg
• UserArg: Combines above 3

Important logical arguments

• OrArg: One of defined arguments
• OptionalArg
• AndArg
• EqualsArg
• OneOf
• ReverseArg: Parses child argument from left to right, instead of right to left as default

Important meta-arguments

• KeyValuesArg: Key-value arguments, the value would be parsed with a child argument
• ListArg: Many of defined child argument, the syntax to split or/and distinguish between items can be configured
• DividedArg: Same as ListArg but doesn't have prefix and postfix, but a split char
• StartsWithArg: Prefix would be omited and child argument would be parsed
• UntilArg: Same as StartsWithArg, but with postfix
• SurroundedArg: An argument with configured prefix and postfix, usually used for text surrounded by "

The list is not full, for more information please check sources of the arguments, they usually have a detailed docstrings.

Advanced usages

Defining our own arguments

This is very simple and there's a few ways to achieve this.

Let's start by simply tweaking the existing arguments.

class ShortTextArg(TextArg):
    def check(self, text: str, entities: ArgEntities) -> bool:
        if len(text) < 3:
            # We use ArgStrictError, because it doesn't get ignored by the OptionalArg or OrArg and would cause an 
            argument typing error message
            raise ArgStrictError("Text too short")
        
        elif len(text) > 10:
            raise ArgStrictError("Text too long")
        
        return True

Alright, so this example will show us something like this:

What if we want to edit the content of the parsed argument? We would just need to edit the parse function and return modified data

class ShortTextArg(TextArg):
    async def parse(self, text: str, offset: int, entities: ArgEntities) -> tuple[int, str]:
        length, text = super().parse(text, offset, entities)

        if len(text) > 10:
            text = text[:10] + "..."

        return length, text

Now, if you want to create a completely new argument that could handle more specific types of arguments and more complicated syntax, please check out the sources for the good starting points.

There's a few pre-made abstract classes to base on:

• ArgFabric: Plain argument fabric, has no limitations. Every argument is based on this class at the end.
• OneWordArgFabricABC: OneWord argument fabric, child version of ArgFabric, can parse only one word.

The good starting point would be ActionTimeArg for the word-argument and UserMentionArg for the argument that can take more text with spaces.

Gathering the arguments specifications of handlers / cmds

Currently, it's being developed under Sophie's codebase Here's the link to the file that specifically extract the modules/handlers/cmds information: https://gitlab.com/SophieBot/sophie/-/blob/beta/sophie_bot/modules/info/utils/extract_info.py

Runtime arguments definition generation

Let's take an example of the following problem: You want to parse the user from the arguments, but you also want the command to support getting the use from the replied message. Since ASS's arguments fabrics does not have any other information except raw text and entities we cannot distinguish those cases. This is where the run-time generation of args specifications comes in handy.

async def optional_user(message: Message | None, _data: dict):
 # message can be None for gathering arguments spec on startup
 if message and message.reply_to_message:
  # Return a blank dictionary
  # Means, the ASS will not parse an arguments in this case (when the message has a replied message)
  return {}

 return {
  'user': UserArg("User")
 }


@router.message(CMDFilter('id'), flags={'args': optional_user})
async def id_cmd(message: Message, user: Optional[Example])
 async def handle(self) -> Any:
  user: Optional[ChatModel] = self.data.get('user', None)

  doc = Doc()

  if self.event.from_user:
   user_id = self.event.from_user.id
   doc += Template(_("Your ID: {id}"), id=Code(user_id))

  if self.event.reply_to_message and self.event.reply_to_message.from_user:
   user_id = self.event.reply_to_message.from_user.id
   doc += Template(_("Replied user ID: {id}"), id=Code(user_id))

  if user:
   doc += Template(
    _("{user}'s ID: {id}"),
    user=UserLink(user_id=user.chat_id, name=user.first_name_or_title),
    id=Code(user.chat_id),
   )

  return await self.event.reply(str(doc))

This approach makes saves the advantages of having the strict arguments specifications but also allows flexibility in cases when you need it.