Passwords without whitespace!

Main.hs

{-# LANGUAGE OverloadedStrings #-}

import Crypto.BCrypt
import Control.Monad.IO.Class
import Data.Text.Lazy
import qualified Data.Text.Encoding as TE
import Data.Maybe (fromJust) -- oh yeah
import Data.Monoid (mconcat)
import Web.Scotty

{- Allow people to enter passwords but don't allow spaces!
   I honestly don't know how this just happens as a side-effect
   of something. -}

main :: IO ()
main = scotty 3000 $ do
  get "/" $ html "<form method=\"post\"><input type=\"password\" name=\"pw\"></form>"
  post "/" $ do
    pw <- param "pw"
    if isInsecure pw
      then do liftIO $ (hash pw >>= storeToDB)
              html $ mconcat ["Your password ", pw, " has been successfully stored!"]
      else html "Your password is too secure"

-- This is where the magic happens!
isInsecure :: Text -> Bool
isInsecure = not . isInfixOf " "

hash :: Text -> IO Text
hash = fmap (fromStrict . TE.decodeUtf8 . fromJust)
       . hashPasswordUsingPolicy slowerBcryptHashingPolicy
       . TE.encodeUtf8
       . toStrict

-- dummies
storeToDB :: Text -> IO ()
storeToDB hash = putStrLn $ "Stored hash in DB: " ++ unpack hash

pwspaces.cabal

name:                pwspaces
version:             0.1.0.0
author:              Vincent Ambo
maintainer:          tazjin@gmail.com
build-type:          Simple
cabal-version:       >=1.10

executable pwspaces
  main-is:             Main.hs
  default-language:    Haskell2010
  build-depends:       base >=4.7 && <4.8,
                       scotty,
                       bcrypt,
                       text,
                       transformers