Description
Haskell web framework (because Scotty had trouble yodeling)
Description
A Haskell web framework heavily influenced by the excellent Scotty, which was in turn influenced by Ruby's Sinatra.
Welshy strives to make it easier to do error handling without overly complicating the control flow. An example:
{-# LANGUAGE OverloadedStrings #-}
import Control.Applicative
import Control.Monad
import qualified Data.Text.Lazy as T
import Network.HTTP.Types
import Web.Welshy
fibs :: [Int]
fibs = 0 : 1 : zipWith (+) fibs (tail fibs)
main :: IO ()
main = welshy 3000 $ do
get "/fibs" $ do
offset <- queryParam "offset" <|> return 0
length <- queryParam "length"
when (offset < 0 || length < 0)
(halt $ status badRequest400)
when (offset + length > 1000)
(halt $ status requestedRangeNotSatisfiable416)
let result = take length $ drop offset fibs
text $ T.pack $ show result
Some of the features demonstrated here:
You can
halt
the current action at any point and continue with a different one.Functions like
queryParam
andjsonParam
have built-in error handling.Welshy's
Action
monad is an instance ofAlternative
.