Network.Linklater

Features:

• Uses Text everywhere so you can send your slash commands crazy Unicode characters all day long.
• Lovely documentation.
• Battle-tested.

Here's a /jpgto bot! If you run this program and then tell Slack about your server (incoming hook and custom slash command) and then type /jpgto diplomatico in one of your channels, you'll get the image from http://diplomatico.jpg.to. How, you say? Screen scraping.

urlParser :: Parser B.ByteString
urlParser = p
  where
    p = garbage *> url
    garbage = string "src="" | (P.take 1 *> garbage)
    url = takeTill (== _quotedbl)

urlFor :: Text -> IO Text
urlFor search = do
  r <- get (T.unpack $ F.format "http://{}.jpg.to/" [search])
  (return . handle . parse urlParser . strictly) (r ^. responseBody)
  where
    strictly = B.concat . L.toChunks
    handle (Fail i ctxs s) = error (show (i, ctxs, s))
    handle (Partial f) = handle (f "")
    handle (Done _ r) = toText r

jpgto :: Maybe Command -> Application
jpgto (Just (Command (User user) channel text)) req respond = do
  url <- urlFor (maybe "spolsky" id text)
  say (Message channel (response url) (EmojiIcon "gift")) config
  (respond . responseLBS status200 headers) ""
  where
    response url = F.format "@{} {}" (user, url)
    config = Config token "trello.slack.com"
    headers = [(Content-Type, "text/plain")]

main :: IO ()
main = do
  let port = 80
  putStrLn (F.format "+ Listening on port {}" [port])
  run port (slash jpgto)
   return ()

For the full example (since this one is missing a ton of imports), see the examples/ directory on GitHub.

https://github.com/hlian/linklater

Documentation

say :: Message -> Config -> IO (Response ByteString)

The say function posts a Message, with a capital M, to Slack. It'll, ahem, need your token first though.

slash :: (Maybe Command -> Application) -> Application

A bot server! As if by magic. This acts like a WAI middleware in that you let us wrap around your application.

data Channel

Where slash commands can come from, and where messages can go.

Constructors

GroupChannel Text

A public or private group.

IMChannel Text

A private conversation with your best friend (or lover?).

Instances

Eq Channel

Ord Channel

Show Channel

newtype User

A username: no at-signs, just text!

Constructors

User Text

Instances

Eq User

Ord User

Show User

data Message

Here's how you talk.

Constructors

Message

Fields

_messageChannel :: Channel

You need a channel. It can be a group channel or a private IM. Alert: if it's a private IM, it'll look like it came from slackbot (as of writing).

_messageText :: Text

What you want to say. This will be parsed in full (parse=full). In the future I'll support other forms of parsing, hopefully. Poke me with a pull request if I forget.

_messageIcon :: Icon

The icon you want your message to appear as.

Instances

Eq Message

Ord Message

Show Message

ToJSON Message

data Config

Like a curiosity about the world, you'll need one of these to say something.

Constructors

Config

Fields

_configIncomingHookToken :: Text

This is the incoming web hook token that Slack gave you. It's usually a long alphanumberic string of garbage.

_configHostname :: Text

This is where your Slack account is hosted. For example, 'trello.slack.com'.

data Command

Incoming HTTP requests to the slash function get parsed into one of these babies.

Constructors

Command

Fields

_commandUser :: User

Who ran your slash command.

_commandChannel :: Channel

Where the person ran your slash command.

_commandText :: Maybe Text

Text for the slash command, if any.

Instances

Eq Command

Ord Command

Show Command

newtype Icon

For example, ":stars2:". Future versions should support actual images, I GUESS.

Constructors

EmojiIcon Text

Instances

Eq Icon

Ord Icon

Show Icon