My IRC bot for node.js. This README file explains the implementation.
- Command restrictedness;
- Joining, parting, quitting, querying.
- Simple Google Books searching;
- Simple RFC searching.
IRC Command processing
The architecture is simple: irc.js can be seen as having two parts:
- One that deals with incoming IRC commands. This is exposed as a single function called process, which takes textual input and returns an object containing information parsed from the command that was interpreted. It also contains a property named ircCmd, which informs the command detected and processed.
- One that produces outgoing commands, for joining, parting, quitting, speaking, renaming and so forth. These are available through a set of functions wrapped in an object called outbound.
The bot's main source file communicates with the irc.js module, feeding it with received messages and receiving from it appropriate objects, containing not only information about the command received, but the values of its arguments in suitably-named properties. From there on, dispatching can happen.
These are objects which determine the bot's behavior that depends on IRC commands. They are dynamically loaded and reloadable. Two examples of dispatchers are exported by public.js and query.js. Besides being advantageous in that resetting is not needed to update behavior, the dispatching mechanism is succint because command names are actually determined by the property names the dispatchers expose. For instance, if foo is a dispatcher and it has a property named 'sayhi', that property's value is invoked receiving as arguments the tokens responsible for its calling and the communication context with information it might need about the bot and its configuration. All dispatchers are property values of the object exported by commands.js. A dispatcher is called precisely like this:
// Assuming 'cmd' is the object exported by commands.js, // and that 'tokens' is an array of tokens parsed from an IRC // messsage: cmd[dispatcher][tokens](tokens, context);
The structure above is purposefully verbose, if cluttered, so as to show the overall mechanism at work. The actual implementation uses more names to hide the ugly syntax.
Every function exposed by a dispatcher (thus, every command) should have a restricted property set to either true or false. Only anthentified users cause dispatch to actually occur.
Context objects are created by the main module and passed on to commands.js. Their purpose is to provide any information needed to carry out whatever processing a dispatcher does (maybe involving additional modules, in which case the dispatcher may augment and/or forward the context object).
Typical information held by context objects include the sender of a message that was received and the options object containing mutalirc's configuration.
Modules may be used to provide additional functionality to mutalirc that is not strictly IRC-related. They are usually interfaces to external APIs. An example is ietf.js, which allows the bot to search for RFCs.
The network module is reponsible for the bot's connection to the IRC server with which it speaks. Its most used interface element is send. It makes sure the given text ends in
\r\n (as required by the RFC) and writes to the connection socket. An exported function called connect starts a connection based on the current configurations and handles required negotiation with the IRC server. No cryptography is employed.