TARS

IRC chatbot for the SCP Wiki, facilitating wiki search and internet outreach automation.

This README contains instructions for command line usage and implementation details. End users looking for command instructions should look at the documentation: https://rossjrw.com/tars

Current state

TARS operated on the SCP IRC network (currently SkipIRC) since March 2019. In that time it's seen two IRC networks, ~1000 users, ~1,000,000 messages, and served ~75,000 requests.

TARS has run on:

• A Chromebook
• A Raspberry Pi 3 Model A+ with a cute little screen
• An AWS EC2 t2.micro instance
• An AWS EC2 t3a.nano instance

As of December 2021, the main instance of TARS is no longer operational, coinciding with the SCP Wiki's move away from IRC.

Installation

TARS uses Poetry for environment management.

git clone https://github.com/rossjrw/tars
cd tars
poetry install

All modules are from PyPI except:

• pyaib, which is forked here: https://github.com/rossjrw/pyaib
• re2, which is forked here: https://github.com/andreasvc/pyre2

re2 will not be installed automatically as it has a specific install process detailed in its README. TARS will operate fine without re2 but will be vulnerable to regular expression attacks.

In order to install the cryptography dependency of pyaib, you may be required to run: sudo apt install build-essential libssl-dev libffi-dev python-dev

TARS requires at least Python 3.8.

Usage

poetry run python3 -m tars [config file] --deferral [deferral config]

The config files I use are in config/.

TARS requires a set of API keys to function correctly. These should be stored in config/keys.secret.toml. More details can be found in helpers/api.py.

TARS will use the nick provided in the config file and NickServ password as defined by the key irc_password in keys.secret.toml.

Building documentation

poetry run python3 -m tars [config file] --deferral [deferral config] --docs

Information from the main config and the deferral config are used in the documentation, so they should be provided for the most accurate output.

Testing

poetry run pytest

Testing is... uh... a little spotty. Tests pass but the suite is not exactly comprehensive.

Adding commands

Each major command should be in its own file. Subcommands can be in the same file as the major command's file.

Create a new file in commands/ named the same as your major command.

Within this file, create a new class named for the major command that extends helpers.basecommand.Command, with the following properties (all of which are optional):

• command_name: The canonical name of this command, used for documentation; if not provided or None, this command will not appear in documentation.
• arguments: A list of dicts, each of which represents an argument for this command. These are passed directly to the argparse add_argument constructor and the keys correspond to its kwargs. However, the following extra keys are accepted:
  • flags: A list of flags for this argument (will be used as the first positional parameter of add_argument).
  • mode: If "hidden", this argument will not appear in documentation.
  • permission: The permission level required to run this command ( currently boolean, with true indicating only a Controller can run it).
  • type: The same as type from argparse, but can also be the following values:
    • tars.helpers.basecommand.regex_type: Checks that the arguments correctly compile to a regex, and exposes the argument values as compiled regex objects.
    • tars.helpers.basecommand.matches_regex(rgx, reason): Checks that the provided string matches regex rgx (can be a Pattern or a string); if it does not, rejects the argument with the given reason. The reason should complete the sentence "Argument rejected because the value..."
    • tars.helpers.basecommand.longstr: Same as str, but the argument values are concatenated with spaces into a single string and exposed as one value. Simulates passing e.g. a sentence as argument value without needing to use quotes. Must be used with a nargs value that would normally expose a list, but will actually expose a single value as if the nargs were None.
• permission: The permission level required to run this command (currently boolean, with true indicating only a Controller can run it).
• arguments_prepend: A string that will be prepended to arguments passed to this command. Useful for setting defaults for subcommands.
• aliases: A list of string aliases for this command. A command with no aliases cannot be called. A subcommand with no defined aliases will use the same aliases as its parent command which probably isn't very useful.

The class' docstring is used as documentation for the command, although only the first line will appear on the command line.

The command must have an instance method called execute, which is called when the command is run, that takes the following arguments (which can be named anything):

• self: The command object. Check for argument presence with 'argname' in self. To get the value of the argument, access self like a dict: self['argname'].
• irc_c: pyaib context
• msg: pyaib message
• cmd: A parsed message-like object, similar to msg but with more properties that are pertinent to this command specifically:
  • ping: Whether the bot was pinged by this message.
  • command: The command name as typed by the user (may differ from the canonical command_name).
  • prefix: The prefix used to call the command e.g. ...

To create a subcommand, create a new class that extends the parent command, with its own docstring and command_name. I recommend using arguments_prepend to add command-line flags and then implement the corresponding functionality in the parent command, but if you must add an execute method to the subcommand, be sure to call the parent's execute method as appropriate.

Edit commands/__init__.py and add any commands you created to the COMMANDS dict along with any aliases as a sub-dict. Your command must have at least one alias, or it won't be able to be called.

Other considerations:

• Arguments may not pass an action to the argparse parser.
• Creating boolean arguments is a little different to normal argparse usage. Normally, you would set default=False and action='store_true', omitting a type. Here, just set type=bool; this is a special case and the action and default value will be handled automatically. nargs must be 0 or omitted.
• A boolean arg is always present (and an 'arg' in self check will always return true) regardless of whether it was actually specified. If it was not specified, its value is false.
• Most nargs values will result in a list being created, except for nargs=None, which expects a single value and returns it directly.
• The default value for nargs of * and + is an empty list, even if no value was actually provided.
• If an argument with nargs of "*" or "?" is not present, 'argname' in self will return false; if it is present but no values were provided, 'argname' in self will return true, even though either way the value is identical ([] for "*" and XXX TODO for "?").

Other bits

A few other important pieces of information:

• msg
  • pyaib's message object
• from helpers.database import DB then DB.xxx() - where xxx represents a function in helpers/database.py
• from helpers.config import CONFIG then CONFIG.xxx to access property xxx of the configuration file