Presage

Okay, most of the shit written here is just empty speak so far. But in my opinion, writing this is fairly easy provided I have a clear plan. One weekend I'll sit down and shit something out! And a lot of this shit will move to documentation.

A cute little bot for IRC and Discord.

Features

• A nice assortment of command modules.
• Message relay among a cluster of channels.
• Decently configurable, but I'm not looking to create k8s-for-IRC.
• Detailed documentation for the source code and user interface.
• Thoroughly tested! Most shit works, at least on my machine~
• Highly concurrent!
• Well designed. This bot can be extended with new listeners and new modules cleanly.

Motivation

I want to write one cute little application with OTP. Elixir and OTP are pretty cool, wouldn't you say?

Design Overview

Actors

• Listeners: Listeners on a chat service. They receive and dispatch messages.
  • Note: One chat protocol can have multiple listeners (e.g. multiple IRC servers).
• Module: A set of functions that act on chat commands.
• Cluster: A set of connected channels. Messages are relayed between channels.
• Aliaser: Stores aliases for commands and can unalias messages.
  • Each cluster has an aliaser.
• Authorizer: Determines the permissions for a user.
  • Each listener has an authorizer.

Data Interfaces

User:

• id: A unique (per-listener) identifier.
• listener_id: A globally unique identifier for the listener this user belongs to.
• mention: A string to use when mentioning the user in a message.
• nickname: A human-readable method of mentioning the user.
• Uniquely identified by (id, listener_id).

MessageInfo:

• raw_message: The raw message received from the listener.
• unaliased_message: The unaliased version of the raw message.
• source_user: The user that sent the message.
• source_cluster: The cluster that this message came from.
• source_listener: The listener that this message came from.

Message Flow

• A message is received in a channel by a listener.
• The listener passes the message to the cluster of the channel.
• The cluster relays the received message to the other member channels.
• The cluster compiles the MessageInfo.
• The cluster passes the MessageInfo to all registered modules.
• The modules pattern match against the unaliased command.
• Each module potentially passes a response to the source cluster.
• The cluster forwards the response to all member channels.

Permissions

Modules can define guard commands with permissions.

The authorizer checks a user's active permissions.

The permissions module provides dynamic permission assignment.

Command Parsing

Modules leverage OptionParser to parse command arguments. This provides well-documented interfaces and detailed error messages with little extra work.

Configuration

TBD. Should just be standard elixir shit.

Modules

Alias

Note: Alias is not strictly one of the modules; it is more significant. However, to an end user, it appears like a module, so I include it here.

Modifies the command aliases.

Example Usage

blissful | .alias new yell "say --uppercase"
presage  | ".yell" aliased to ".say --uppercase".
blissful | .yell u wot m8
presage  | U WOT M8

Say

Echoes bot output.

Example Usage

blissful | .say hi
presage  | hi

Permissions

Configures per-user permissions. Permissions can be granted globally or for a single cluster.

Example Usage

blissful | .permissions add blissful "alias/delete"
presage  | Gave blissful the permission "alias/delete".
blissful | .alias delete yell
presage  | Deleted the alias ".yell" (was ".say --uppercase").