yesod/yesod-auth/Yesod/Auth/Facebook.hs
Michael Snoyman 61f0c26e9f MonadLift
2011-12-30 13:30:24 +02:00

123 lines
4.1 KiB
Haskell

{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE OverloadedStrings #-}
module Yesod.Auth.Facebook
( authFacebook
, facebookLogin
, facebookUrl
, facebookLogout
, getFacebookAccessToken
) where
#include "qq.h"
import Yesod.Auth
import qualified Web.Authenticate.Facebook as Facebook
import Data.Aeson
import Data.Aeson.Types (parseMaybe)
import Data.Maybe (fromMaybe)
import Yesod.Form
import Yesod.Handler
import Yesod.Widget
import Control.Monad.IO.Class (MonadIO, liftIO)
import Data.Text (Text)
import Control.Monad (liftM, mzero, when)
import Data.Monoid (mappend)
import qualified Data.Aeson.Types
import qualified Yesod.Auth.Message as Msg
-- | Route for login using this authentication plugin.
facebookLogin :: AuthRoute
facebookLogin = PluginR "facebook" ["forward"]
-- | This is just a synonym of 'facebookLogin'. Deprecated since
-- @yesod-auth 0.7.8@, please use 'facebookLogin' instead.
facebookUrl :: AuthRoute
facebookUrl = facebookLogin
{-# DEPRECATED facebookUrl "Please use facebookLogin instead." #-}
-- | Route for logout using this authentication plugin. Per
-- Facebook's policies
-- (<https://developers.facebook.com/policy/>), the user needs to
-- logout from Facebook itself as well.
facebookLogout :: AuthRoute
facebookLogout = PluginR "facebook" ["logout"]
-- | Get Facebook's access token from the session. Returns
-- @Nothing@ if it's not found (probably because the user is not
-- logged in via Facebook). Note that the returned access token
-- may have expired.
getFacebookAccessToken :: GHandler sub master (Maybe Facebook.AccessToken)
getFacebookAccessToken =
liftM (fmap Facebook.AccessToken) (lookupSession facebookAccessTokenKey)
-- | Key used to store Facebook's access token in the client
-- session.
facebookAccessTokenKey :: Text
facebookAccessTokenKey = "_FB"
-- | Authentication plugin using Facebook.
authFacebook :: YesodAuth m
=> Text -- ^ Application ID
-> Text -- ^ Application secret
-> [Text] -- ^ Requested permissions
-> AuthPlugin m
authFacebook cid secret perms =
AuthPlugin "facebook" dispatch login
where
url = PluginR "facebook" []
dispatch "GET" ["forward"] = do
tm <- getRouteToMaster
render <- getUrlRender
let fb = Facebook.Facebook cid secret $ render $ tm url
redirectText RedirectTemporary $ Facebook.getForwardUrl fb perms
dispatch "GET" [] = do
render <- getUrlRender
tm <- getRouteToMaster
let fb = Facebook.Facebook cid secret $ render $ tm url
code <- runInputGet $ ireq textField "code"
at <- liftIO $ Facebook.getAccessToken fb code
let Facebook.AccessToken at' = at
setSession facebookAccessTokenKey at'
so <- liftIO $ Facebook.getGraphData at "me"
let c = fromMaybe (error "Invalid response from Facebook")
$ parseMaybe (parseCreds at') $ either error id so
setCreds True c
dispatch "GET" ["logout"] = do
m <- getYesod
tm <- getRouteToMaster
mtoken <- getFacebookAccessToken
when (redirectToReferer m) setUltDestReferer
case mtoken of
Nothing -> do
-- Well... then just logout from our app.
redirect RedirectTemporary (tm LogoutR)
Just at -> do
render <- getUrlRender
let logout = Facebook.getLogoutUrl at (render $ tm LogoutR)
redirectText RedirectTemporary logout
dispatch _ _ = notFound
login tm = do
render <- lift getUrlRender
let fb = Facebook.Facebook cid secret $ render $ tm url
let furl = Facebook.getForwardUrl fb $ perms
[QQ(whamlet)|
<p>
<a href="#{furl}">_{Msg.Facebook}
|]
parseCreds :: Text -> Value -> Data.Aeson.Types.Parser (Creds m)
parseCreds at' (Object m) = do
id' <- m .: "id"
let id'' = "http://graph.facebook.com/" `mappend` id'
name <- m .:? "name"
email <- m .:? "email"
return
$ Creds "facebook" id''
$ maybe id (\x -> (:) ("verifiedEmail", x)) email
$ maybe id (\x -> (:) ("displayName ", x)) name
[ ("accessToken", at')
]
parseCreds _ _ = mzero