RC "Database server"

Main.hs

import           Control.Concurrent.MVar
import qualified Data.Map as M
import           Network.HTTP.Types.Status
import           Web.Scotty

import           Protolude hiding (get)

main :: IO ()
main = do
  dbSync <- newMVar M.empty

  scotty 4000 $ do
    get "/set" $ do
      db <- liftIO $ takeMVar dbSync
      newVals <- M.fromList <$> params
      liftIO . putMVar dbSync $ M.union newVals db

    get "/get" $ do
      k <- param "key"
      db <- liftIO $ readMVar dbSync
      case M.lookup k db of
        Nothing  -> status status404
        (Just v) -> text v

rc.cabal

name:          rc
version:       0.0.0
cabal-version: >= 1.8
build-type:    Simple

executable        rc
  hs-source-dirs: .
  main-is:        Main.hs
  ghc-options:    -Wall -threaded -O2 -rtsopts -with-rtsopts=-N
  extensions:     OverloadedStrings, NoImplicitPrelude
  build-depends:  base   >= 4      && < 5
                , containers
                , http-types
                , protolude
                , scotty