The features of this web framework:

• Type safe routes, specify url-handler mapping in one place. For example, we want a url mapping for blog as "/blog/year-month-day" to Handler Int Int Int, where year, month and day are integers. We can declare as follows:

    data Blog = Blog Int Int Int deriving (Show, Eq, Typeable)
    $(defineIsomorphisms ''Blog)

    instance Handler Blog where

   get b@(Blog y m d) _ = do
        t <- liftIO getClockTime
        return $ responseHtml $ trans' "blog" ++ show b ++ show t

We can reverse this mapping from handler value automatically, thus don't need to construct url string manually in code, avoiding url errors.

ghci>url (Blog 2011 9 19) == "/blog/2011-9-19"

• Simple yet elegant handler via type class.

class Handler a where
    get, post, put, delete, handle :: a -> Application
    handle a req = case requestMethod req of
        m | m == methodGet -> get a req
          | m == methodPost -> post a req
          | m == methodPut -> put a req
          | m == methodDelete -> delete a req
        otherwise -> unimplemented req

• Flexible template system, utilize exsisting libraries such as Blaze-Html and Hastache.

• Easy i18n

• TODO: Auth system

Port from snap-auth.

• TODO: Modular app system like Django

• TODO: Persistent library

Improving the DSH library is my current preference.

For the example code listed above, please refer to https://github.com/lilac/ivy-example/