256 lines
8 KiB
Haskell
256 lines
8 KiB
Haskell
{- Yesod webapp
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-
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- Copyright 2012-2014 Joey Hess <id@joeyh.name>
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-
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- License: BSD-2-clause
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-}
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{-# LANGUAGE OverloadedStrings, CPP, RankNTypes #-}
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module Utility.WebApp where
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import Common
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import Utility.Tmp
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import Utility.FileMode
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import Utility.Hash
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import qualified Yesod
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import qualified Network.Wai as Wai
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import Network.Wai.Handler.Warp
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import Network.Wai.Handler.WarpTLS
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import Network.HTTP.Types
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import qualified Data.CaseInsensitive as CI
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import Network.Socket
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import "crypto-api" Crypto.Random
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import qualified Web.ClientSession as CS
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import qualified Data.ByteString.Lazy as L
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import qualified Data.ByteString as B
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import qualified Data.Text as T
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import qualified Data.Text.Encoding as TE
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import Blaze.ByteString.Builder.Char.Utf8 (fromText)
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import Blaze.ByteString.Builder (Builder)
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import Control.Arrow ((***))
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import Control.Concurrent
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#ifdef WITH_WEBAPP_SECURE
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import Data.SecureMem
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import Data.Byteable
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#endif
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#ifdef __ANDROID__
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import Data.Endian
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#endif
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localhost :: HostName
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localhost = "localhost"
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{- Builds a command to use to start or open a web browser showing an url. -}
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browserProc :: String -> CreateProcess
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#ifdef darwin_HOST_OS
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browserProc url = proc "open" [url]
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#else
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#ifdef __ANDROID__
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-- Warning: The `am` command does not work very reliably on Android.
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browserProc url = proc "am"
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["start", "-a", "android.intent.action.VIEW", "-d", url]
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#else
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#ifdef mingw32_HOST_OS
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-- Warning: On Windows, no quoting or escaping of the url seems possible,
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-- so spaces in it will cause problems. One approach is to make the url
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-- be a relative filename, and adjust the returned CreateProcess to change
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-- to the directory it's in.
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browserProc url = proc "cmd" ["/c start " ++ url]
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#else
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browserProc url = proc "xdg-open" [url]
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#endif
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#endif
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#endif
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{- Binds to a socket on localhost, or possibly a different specified
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- hostname or address, and runs a webapp on it.
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-
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- An IO action can also be run, to do something with the address,
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- such as start a web browser to view the webapp.
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-}
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runWebApp :: Maybe TLSSettings -> Maybe HostName -> Wai.Application -> (SockAddr -> IO ()) -> IO ()
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runWebApp tlssettings h app observer = withSocketsDo $ do
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sock <- getSocket h
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void $ forkIO $ go webAppSettings sock app
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sockaddr <- fixSockAddr <$> getSocketName sock
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observer sockaddr
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where
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#ifdef WITH_WEBAPP_SECURE
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go = (maybe runSettingsSocket (\ts -> runTLSSocket ts) tlssettings)
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#else
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go = runSettingsSocket
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#endif
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fixSockAddr :: SockAddr -> SockAddr
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#ifdef __ANDROID__
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{- On Android, the port is currently incorrectly returned in network
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- byte order, which is wrong on little endian systems. -}
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fixSockAddr (SockAddrInet (PortNum port) addr) = SockAddrInet (PortNum $ swapEndian port) addr
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#endif
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fixSockAddr addr = addr
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-- disable buggy sloworis attack prevention code
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webAppSettings :: Settings
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webAppSettings = setTimeout halfhour defaultSettings
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where
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halfhour = 30 * 60
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{- Binds to a local socket, or if specified, to a socket on the specified
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- hostname or address. Selects any free port, unless the hostname ends with
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- ":port"
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-
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- Prefers to bind to the ipv4 address rather than the ipv6 address
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- of localhost, if it's available.
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-}
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getSocket :: Maybe HostName -> IO Socket
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getSocket h = do
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#if defined(__ANDROID__) || defined (mingw32_HOST_OS)
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-- getAddrInfo currently segfaults on Android.
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-- The HostName is ignored by this code.
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when (isJust h) $
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error "getSocket with HostName not supported on this OS"
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addr <- inet_addr "127.0.0.1"
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sock <- socket AF_INET Stream defaultProtocol
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preparesocket sock
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bindSocket sock (SockAddrInet aNY_PORT addr)
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use sock
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where
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#else
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addrs <- getAddrInfo (Just hints) (Just hostname) Nothing
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case (partition (\a -> addrFamily a == AF_INET) addrs) of
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(v4addr:_, _) -> go v4addr
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(_, v6addr:_) -> go v6addr
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_ -> error "unable to bind to a local socket"
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where
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hostname = fromMaybe localhost h
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hints = defaultHints { addrSocketType = Stream }
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{- Repeated attempts because bind sometimes fails for an
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- unknown reason on OSX. -}
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go addr = go' 100 addr
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go' :: Int -> AddrInfo -> IO Socket
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go' 0 _ = error "unable to bind to local socket"
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go' n addr = do
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r <- tryIO $ bracketOnError (open addr) sClose (useaddr addr)
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either (const $ go' (pred n) addr) return r
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open addr = socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
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useaddr addr sock = do
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preparesocket sock
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bindSocket sock (addrAddress addr)
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use sock
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#endif
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preparesocket sock = setSocketOption sock ReuseAddr 1
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use sock = do
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listen sock maxListenQueue
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return sock
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lookupRequestField :: CI.CI B.ByteString -> Wai.Request -> B.ByteString
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lookupRequestField k req = fromMaybe "" . lookup k $ Wai.requestHeaders req
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{- Rather than storing a session key on disk, use a random key
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- that will only be valid for this run of the webapp. -}
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webAppSessionBackend :: Yesod.Yesod y => y -> IO (Maybe Yesod.SessionBackend)
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webAppSessionBackend _ = do
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g <- newGenIO :: IO SystemRandom
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case genBytes 96 g of
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Left e -> error $ "failed to generate random key: " ++ show e
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Right (s, _) -> case CS.initKey s of
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Left e -> error $ "failed to initialize key: " ++ show e
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Right key -> use key
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where
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timeout = 120 * 60 -- 120 minutes
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use key =
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Just . Yesod.clientSessionBackend key . fst
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<$> Yesod.clientSessionDateCacher timeout
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#ifdef WITH_WEBAPP_SECURE
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type AuthToken = SecureMem
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#else
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type AuthToken = T.Text
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#endif
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toAuthToken :: T.Text -> AuthToken
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#ifdef WITH_WEBAPP_SECURE
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toAuthToken = secureMemFromByteString . TE.encodeUtf8
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#else
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toAuthToken = id
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#endif
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fromAuthToken :: AuthToken -> T.Text
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#ifdef WITH_WEBAPP_SECURE
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fromAuthToken = TE.decodeLatin1 . toBytes
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#else
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fromAuthToken = id
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#endif
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{- Generates a random sha512 string, encapsulated in a SecureMem,
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- suitable to be used for an authentication secret. -}
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genAuthToken :: IO AuthToken
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genAuthToken = do
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g <- newGenIO :: IO SystemRandom
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return $
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case genBytes 512 g of
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Left e -> error $ "failed to generate auth token: " ++ show e
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Right (s, _) -> toAuthToken $ T.pack $ show $ sha512 $ L.fromChunks [s]
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{- A Yesod isAuthorized method, which checks the auth cgi parameter
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- against a token extracted from the Yesod application.
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-
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- Note that the usual Yesod error page is bypassed on error, to avoid
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- possibly leaking the auth token in urls on that page!
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-}
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checkAuthToken :: (Monad m, Yesod.MonadHandler m) => (Yesod.HandlerSite m -> AuthToken) -> m Yesod.AuthResult
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checkAuthToken extractAuthToken = do
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webapp <- Yesod.getYesod
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req <- Yesod.getRequest
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let params = Yesod.reqGetParams req
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if (toAuthToken <$> lookup "auth" params) == Just (extractAuthToken webapp)
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then return Yesod.Authorized
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else Yesod.sendResponseStatus unauthorized401 ()
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{- A Yesod joinPath method, which adds an auth cgi parameter to every
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- url matching a predicate, containing a token extracted from the
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- Yesod application.
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-
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- A typical predicate would exclude files under /static.
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-}
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insertAuthToken :: forall y. (y -> AuthToken)
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-> ([T.Text] -> Bool)
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-> y
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-> T.Text
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-> [T.Text]
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-> [(T.Text, T.Text)]
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-> Builder
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insertAuthToken extractAuthToken predicate webapp root pathbits params =
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fromText root `mappend` encodePath pathbits' encodedparams
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where
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pathbits' = if null pathbits then [T.empty] else pathbits
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encodedparams = map (TE.encodeUtf8 *** go) params'
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go "" = Nothing
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go x = Just $ TE.encodeUtf8 x
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authparam = (T.pack "auth", fromAuthToken (extractAuthToken webapp))
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params'
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| predicate pathbits = authparam:params
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| otherwise = params
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{- Creates a html shim file that's used to redirect into the webapp,
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- to avoid exposing the secret token when launching the web browser. -}
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writeHtmlShim :: String -> String -> FilePath -> IO ()
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writeHtmlShim title url file = viaTmp writeFileProtected file $ genHtmlShim title url
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{- TODO: generate this static file using Yesod. -}
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genHtmlShim :: String -> String -> String
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genHtmlShim title url = unlines
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[ "<html>"
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, "<head>"
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, "<title>"++ title ++ "</title>"
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, "<meta http-equiv=\"refresh\" content=\"1; URL="++url++"\">"
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, "<body>"
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, "<p>"
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, "<a href=\"" ++ url ++ "\">" ++ title ++ "</a>"
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, "</p>"
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, "</body>"
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, "</html>"
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]
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