Hello,
I have just released a new library on hackage called ircbot. (Because
that is what Haskell really needs -- another irc bot library).
http://hackage.haskell.org/package/ircbot
A demo app is here:
http://patch-tag.com/r/stepcut/ircbot/snapshot/current/content/pretty/demo.hs
The demo is pretty non-thrilling. 98% of it is parsing command-line
arguments, and then it calls a simple bot with two parts:
pingPart - part that handles server PING/PONG requests
dicePart - a simple part that lets you roll dice
Here is an example session:
<stepcut> synthea: dice 3d4+12
<synthea> You rolled 3 4-sided dice with a +12 modifier: [1,3,4] => 20
The primary reason this library exists is that a long time ago, I
needed a way to log the #happs channel. So I coded up a little logging
bot using the irc library from hackage.
Then later I decided to fork the irc logging out of the happstack.com
server itself and into a resuable irc bot library.
The library has the following features:
1. a reconnect loop that tries really hard to make sure the bot
notices if it is disconnected and tries to reconnect.
2. a channel logging facility that automatically rolls over to a new
log file every day.
3. a BotMonad class and BotPartT monad which make it easy to create
handlers for incoming messages:
http://patch-tag.com/r/stepcut/ircbot/snapshot/current/content/pretty/Network/IRC/Bot/BotMonad.hs
Each bot part is run in its own thread. Incoming messages are
delivered to all the parts. That is useful because some parts, like
the seen command, need to see every incoming message, even if they do
not actively respond to them. Because the parts are handled by
different threads, they do not block each other.
By default, each part is single-threaded. That is because some parts
may need to see multiple messages and see them in the order they
originally arrived. However, a part can easily call forkIO to handle
each incoming Message and avoid blocking when appropriate.
4. a wrapper that let's you use Parsec to parse an incoming message.
It is used by the dicePart:
http://patch-tag.com/r/stepcut/ircbot/snapshot/current/content/pretty/Network/IRC/Bot/Part/Dice.hs
Using parsec gives you an easy way to specify syntax errors:
<stepcut> synthea: dice
<synthea> unexpected end of input; expecting dice <num-dice>d<num-
sides>[+<modifier>]
Future work:
1. The library is based around the old String based irc library. Would
be nice to upgrade to something that used ByteStrings+Text+Builder.
Practically speaking.. it's IRC. The maximum line length is 510
characters, and the bot typically needs to handle, at most, a few
messages per second. So, space and time issues would only be a
practical concern if your bot is joining hundreds of channels. But,
that is no excused not to use Text :) Perhaps the fastirc library?
2. The channel logging feature needs some minor changes so that more
than one channel at a time can be logged
3. the bot needs to do something sane if the nick it wants is already
in use. It should also support nick registration.
4. needs automatic help text generation
5. documentation
6. It should be possible to support dynamically reloadable plugins.
Most of the technology exists in happstack-plugins + plugins. We just
need to finish splitting happstack-plugins into two packages.
7. clustering support. ircbot does not have any built-in persistent
storage. It should work fine with acid-state, SQL, etc. When acid-
state gets multimaster replication support, it would be nice if there
was an automatic failover system. Basically, you could have two or
more bots in the channel using acid-state replication. Queries would
normally be answered by the primary bot, but if the primary bot goes
offline, the secondary bot could answer the queries instead.
8. windows support - the channel logging feature uses the unix
package, which is not supported on Windows. The rest of the code is
already portable.
Anyway. Enjoy!
- Jeremy
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