{-# LANGUAGE OverloadedStrings #-} import Web.Scotty import Network.Wai.Middleware.RequestLogger -- install wai-extra if you don't have this import Control.Monad.Trans import Data.Monoid import System.Random (newStdGen, randomRs) import Network.HTTP.Types (status302) import Network.Wai import qualified Data.Text.Lazy as T import Data.Text.Lazy.Encoding (decodeUtf8) main :: IO () main = scotty 3000 $ do -- Add any WAI middleware, they are run top-down. middleware logStdoutDev -- get (function $ \req -> Just [("version", T.pack $ show $ httpVersion req)]) $ do -- v <- param "version" -- text v -- To demonstrate that routes are matched top-down. get "/" $ text "foobar" get "/" $ text "barfoo" -- Using a parameter in the query string. If it has -- not been given, a 500 page is generated. get "/foo" $ do v <- param "fooparam" html $ mconcat ["

", v, "

"] -- An uncaught error becomes a 500 page. get "/raise" $ raise "some error here" -- You can set status and headers directly. get "/redirect-custom" $ do status status302 header "Location" "http://www.google.com" -- note first arg to header is NOT case-sensitive -- redirects preempt execution get "/redirect" $ do redirect "http://www.google.com" raise "this error is never reached" -- Of course you can catch your own errors. get "/rescue" $ do (do raise "a rescued error"; redirect "http://www.we-never-go-here.com") `rescue` (\m -> text $ "we recovered from " `mappend` m) -- Parts of the URL that start with a colon match -- any string, and capture that value as a parameter. -- URL captures take precedence over query string parameters. get "/foo/:bar/required" $ do v <- param "bar" html $ mconcat ["

", v, "

"] -- Files are streamed directly to the client. get "/404" $ file "404.html" get "/random" $ do next redirect "http://www.we-never-go-here.com" -- You can do IO with liftIO, and you can return JSON content. get "/random" $ do g <- liftIO newStdGen json $ take 20 $ randomRs (1::Int,100) g get "/ints/:is" $ do is <- param "is" json $ [(1::Int)..10] ++ is get "/setbody" $ do html $ mconcat ["
" ,"" ,"" ,"
" ] post "/readbody" $ do b <- body text $ decodeUtf8 b get "/lambda/:foo/:bar/:baz" $ \ foo bar baz -> do text $ mconcat [foo, bar, baz] get "/reqHeader" $ do agent <- reqHeader "User-Agent" text agent {- If you don't want to use Warp as your webserver, you can use any WAI handler. import Network.Wai.Handler.FastCGI (run) main = do myApp <- scottyApp $ do get "/" $ text "hello world" run myApp -}