Added openid.hs sample for yesod-auth

yesod-auth/openid.hs

@@ -0,0 +1,48 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+import Yesod.Core
+import Yesod.Auth
+import Yesod.Auth.OpenId
+import Data.Text (Text)
+import Text.Hamlet (hamlet)
+import Control.Monad.IO.Class (liftIO)
+import Yesod.Form
+import Network.Wai.Handler.Warp (run)
+
+data BID = BID
+
+mkYesod "BID" [parseRoutes|
+/ RootR GET
+/after AfterLoginR GET
+/auth AuthR Auth getAuth
+|]
+
+getRootR :: Handler ()
+getRootR = redirect RedirectTemporary $ AuthR LoginR
+
+getAfterLoginR :: Handler RepHtml
+getAfterLoginR = do
+    mauth <- maybeAuthId
+    defaultLayout $ addHamlet [hamlet|
+<p>Auth: #{show mauth}
+|]
+
+instance Yesod BID where
+    approot _ = "http://localhost:3000"
+
+instance YesodAuth BID where
+    type AuthId BID = Text
+    loginDest _ = AfterLoginR
+    logoutDest _ = AuthR LoginR
+    getAuthId = return . Just . credsIdent
+    authPlugins = [authOpenId]
+
+instance RenderMessage BID FormMessage where
+    renderMessage _ _ = defaultFormMessage
+
+main :: IO ()
+main = toWaiApp BID >>= run 3000
+