107 lines
3.6 KiB
Haskell
107 lines
3.6 KiB
Haskell
{-# LANGUAGE DataKinds #-}
|
|
{-# LANGUAGE DeriveGeneric #-}
|
|
{-# LANGUAGE FlexibleInstances #-}
|
|
{-# LANGUAGE OverloadedStrings #-}
|
|
{-# LANGUAGE ScopedTypeVariables #-}
|
|
{-# LANGUAGE TypeFamilies #-}
|
|
{-# LANGUAGE TypeOperators #-}
|
|
import Data.Aeson
|
|
import Data.ByteString (ByteString)
|
|
import Data.Text (Text)
|
|
import GHC.Generics
|
|
import Network.HTTP.Types
|
|
import Network.Wai
|
|
import Network.Wai.Handler.Warp
|
|
import Servant
|
|
import Servant.Server.Internal
|
|
import Data.Aeson
|
|
import Data.ByteString (ByteString)
|
|
import Data.ByteString.Builder.Internal (byteStringCopy)
|
|
import Data.Monoid ((<>))
|
|
import Data.Text (Text)
|
|
import GHC.Generics
|
|
import Network.HTTP.Types
|
|
import Network.Wai
|
|
import Network.Wai.Handler.Warp
|
|
import Servant
|
|
import Servant.API.Authentication
|
|
import Servant.Server.Internal
|
|
import Servant.Server.Internal.Authentication (strictProtect, AuthHandlers(AuthHandlers))
|
|
|
|
-- | An example of a custom authentication framework that checks a Cookie for a
|
|
-- value.
|
|
|
|
-- | Data we will use to test for authentication
|
|
data CookieAuth = CookieAuth { cookie :: ByteString }
|
|
|
|
-- | a 'User' datatype we get once the authentication data is tested.
|
|
type User = ByteString
|
|
|
|
-- | we will look up authentication data in the database and extract a User.
|
|
type DBLookup = CookieAuth -> IO (Maybe User)
|
|
|
|
-- | method that tests for authentication and extracts a User type.
|
|
isGoodCookie :: DBLookup
|
|
isGoodCookie (CookieAuth cookie) = if cookie == "good cookie" then return (Just "one user") else return Nothing
|
|
|
|
-- | Response handlers: what do we do when authentication doesn't work.
|
|
cookieAuthHandlers :: AuthHandlers CookieAuth
|
|
cookieAuthHandlers = AuthHandlers missingAuth notAuthenticated
|
|
where
|
|
missingAuth :: IO Response
|
|
missingAuth = return $ (responseBuilder status401 [] "Missing Cookie header.")
|
|
|
|
notAuthenticated :: CookieAuth -> IO Response
|
|
notAuthenticated (CookieAuth cookie) = return $
|
|
responseBuilder status401 [] ("Invalid cookie: " <> byteStringCopy cookie)
|
|
|
|
-- | 'AuthData' is a typeclass that provides a method to extract authentication
|
|
-- data from a 'Reqest'
|
|
instance AuthData CookieAuth where
|
|
authData req = fmap CookieAuth (lookup "Cookie" (requestHeaders req))
|
|
|
|
-- | some data we will return from our API that is protected
|
|
newtype PrivateData = PrivateData { ssshhh :: Text }
|
|
deriving (Eq, Show, Generic)
|
|
|
|
instance ToJSON PrivateData
|
|
|
|
-- | Some data we will return from our API that is not protected
|
|
newtype PublicData = PublicData { somedata :: Text }
|
|
deriving (Eq, Show, Generic)
|
|
|
|
instance ToJSON PublicData
|
|
|
|
-- | Private API (will require authentication) as a type
|
|
type PrivateAPI = Get '[JSON] [PrivateData]
|
|
|
|
-- | Public API (non-authenticated) as a type
|
|
type PublicAPI = Get '[JSON] [PublicData]
|
|
|
|
-- | Our full API as a type with authentication
|
|
type API = AuthProtect CookieAuth User 'Strict :> "private" :> PrivateAPI
|
|
:<|> PublicAPI
|
|
|
|
api :: Proxy API
|
|
api = Proxy
|
|
|
|
server :: Server API
|
|
server = strictProtect isGoodCookie (const (return prvdata)) cookieAuthHandlers
|
|
:<|> return pubdata
|
|
|
|
where prvdata = [PrivateData "this is a secret"]
|
|
pubdata = [PublicData "this is a public piece of data"]
|
|
|
|
main :: IO ()
|
|
main = run 8080 (serve api server)
|
|
|
|
{- Sample session:
|
|
$ curl http://localhost:8080/
|
|
[{"somedata":"this is a public piece of data"}]
|
|
$ curl http://localhost:8080/private
|
|
Missing auth header.
|
|
$ curl -H "Cookie: good password" http://localhost:8080/private
|
|
[{"ssshhh":"this is a secret"}]
|
|
$ curl -H "Cookie: bad password" http://localhost:8080/private
|
|
Invalid cookie.
|
|
-}
|