Main.hs

{-# LANGUAGE DeriveGeneric     #-}
{-# LANGUAGE OverloadedStrings #-}
module Main where

import           Web.Spock
import           Web.Spock.Config

import           Control.Monad.Trans
import           Data.Aeson          hiding (json)
import           Data.IORef
import           Data.Monoid
import qualified Data.Text           as T
import           GHC.Generics

import   Network.HTTP.Types.Status

data MySession = EmptySession
newtype MyAppState = DummyAppState (IORef Int)

data User = User {
  login:: String,
  pass  :: String
} deriving (Generic, Show)

instance ToJSON User
instance FromJSON User

main :: IO ()
main =
    do ref <- newIORef 0
       spockCfg <- defaultSpockCfg EmptySession PCNoDatabase (DummyAppState ref)
       runSpock 8080 (spock spockCfg app)


type ApiAction a = SpockAction  () MySession MyAppState a


app :: SpockM () MySession MyAppState ()
app =
    do get root $
           text "Hello World!"
       get ("hello" <//> var) $ \name ->
           do (DummyAppState ref) <- getState
              visitorNumber <- liftIO $ atomicModifyIORef' ref $ \i -> (i+1, i+1)
              text ("Hello " <> name <> ", you are visitor number " <> T.pack (show visitorNumber))
       post "login" $ do
         usr <- jsonBody' :: ApiAction User
         case usr of
           User "admin" "admin" -> json $ object ["yolo" .= String "success"]
           _ -> do setStatus status401
                   json $ object ["yolo" .= String "fail"]

project.cabal

name:                seminaire-diverse2017-spock
version:             0.1.0.0
-- synopsis:
-- description:
homepage:            https://github.com/githubuser/seminaire-diverse2017-spock#readme
license:             BSD3
license-file:        LICENSE
author:              Author name here
maintainer:          example@example.com
copyright:           2017 Author name here
category:            Web
build-type:          Simple
extra-source-files:  README.md
cabal-version:       >=1.10

executable seminaire-diverse2017-spock
  hs-source-dirs:      app
  main-is:             Main.hs
  default-language:    Haskell2010
  build-depends:       base >= 4.7 && < 5
                     , Spock >= 0.11
                     , mtl
                     , text
                     , aeson
                     , http-types