yesod/Yesod/Yesod.hs
2010-04-11 23:17:21 -07:00

225 lines
7.0 KiB
Haskell

{-# LANGUAGE QuasiQuotes #-}
-- | The basic typeclass for a Yesod application.
module Yesod.Yesod
( Yesod (..)
, YesodSite (..)
, applyLayout'
, applyLayoutJson
, getApproot
, toWaiApp
, basicHandler
) where
import Data.Object.Html
import Data.Object.Json (unJsonDoc)
import Yesod.Response
import Yesod.Request
import Yesod.Definitions
import Yesod.Handler
import qualified Data.ByteString as B
import qualified Data.ByteString.Char8 as B8
import Data.Maybe (fromMaybe)
import Web.Mime
import Web.Encodings (parseHttpAccept)
import Web.Routes (Site (..), encodePathInfo, decodePathInfo)
import Data.List (intercalate)
import Text.Hamlet hiding (Content, Html) -- FIXME do not export
import qualified Text.Hamlet as Hamlet
import qualified Network.Wai as W
import Network.Wai.Middleware.CleanPath
import Network.Wai.Middleware.ClientSession
import Network.Wai.Middleware.Jsonp
import Network.Wai.Middleware.MethodOverride
import Network.Wai.Middleware.Gzip
import qualified Network.Wai.Handler.SimpleServer as SS
import qualified Network.Wai.Handler.CGI as CGI
import System.Environment (getEnvironment)
class YesodSite y where
getSite :: ((String -> YesodApp y) -> YesodApp y) -- ^ get the method
-> YesodApp y -- ^ bad method
-> y
-> Site (Routes y) (YesodApp y)
data PageContent url = PageContent
{ pageTitle :: Hamlet url IO Hamlet.Html
, pageHead :: Hamlet url IO ()
, pageBody :: Hamlet url IO ()
}
simpleContent :: String -> Hamlet.Html -> PageContent url
simpleContent title body = PageContent
{ pageTitle = return $ Unencoded $ cs title
, pageHead = return ()
, pageBody = outputHtml body
}
class YesodSite a => Yesod a where
-- | The encryption key to be used for encrypting client sessions.
encryptKey :: a -> IO Word256
encryptKey _ = getKey defaultKeyFile
-- | Number of minutes before a client session times out. Defaults to
-- 120 (2 hours).
clientSessionDuration :: a -> Int
clientSessionDuration = const 120
-- | Output error response pages.
errorHandler :: ErrorResponse -> Handler a ChooseRep
errorHandler = defaultErrorHandler
-- | Applies some form of layout to <title> and <body> contents of a page.
applyLayout :: a
-> PageContent (Routes a)
-> Request
-> Hamlet (Routes a) IO ()
applyLayout _ p _ = [$hamlet|
<!DOCTYPE html>
%html
%head
%title $pageTitle$
^pageHead^
%body
^pageBody^
|] p
-- | Gets called at the beginning of each request. Useful for logging.
onRequest :: a -> Request -> IO ()
onRequest _ _ = return ()
-- | An absolute URL to the root of the application. Do not include
-- trailing slash.
approot :: a -> Approot
-- | A convenience wrapper around 'applyLayout'.
applyLayout' :: Yesod y
=> String
-> Html
-> Handler y ChooseRep
applyLayout' t b = do
let pc = simpleContent t $ Encoded $ cs $ unHtmlFragment $ cs b
y <- getYesod
rr <- getRequest
content <- hamletToContent $ applyLayout y pc rr
return $ chooseRep
[ (TypeHtml, content)
]
-- | A convenience wrapper around 'applyLayout' which provides a JSON
-- representation of the body.
applyLayoutJson :: Yesod y
=> String
-> HtmlObject
-> Handler y ChooseRep
applyLayoutJson t b = do
let pc = simpleContent t $ Encoded $ cs $ unHtmlFragment
$ cs (cs b :: Html)
y <- getYesod
rr <- getRequest
htmlcontent <- hamletToContent $ applyLayout y pc rr
return $ chooseRep
[ (TypeHtml, htmlcontent)
, (TypeJson, cs $ unJsonDoc $ cs b)
]
hamletToContent :: Hamlet (Routes y) IO () -> Handler y Content
hamletToContent h = do
render <- getUrlRender
return $ ContentEnum $ go render
where
go render iter seed = do
res <- runHamlet h render seed $ iter' iter
case res of
Left x -> return $ Left x
Right ((), x) -> return $ Right x
iter' iter seed text = iter seed $ cs text
getApproot :: Yesod y => Handler y Approot
getApproot = approot `fmap` getYesod
defaultErrorHandler :: Yesod y
=> ErrorResponse
-> Handler y ChooseRep
defaultErrorHandler NotFound = do
r <- waiRequest
applyLayout' "Not Found" $ cs $ toHtmlObject
[ ("Not found", cs $ W.pathInfo r :: String)
]
defaultErrorHandler PermissionDenied =
applyLayout' "Permission Denied" $ cs "Permission denied"
defaultErrorHandler (InvalidArgs ia) =
applyLayout' "Invalid Arguments" $ cs $ toHtmlObject
[ ("errorMsg", toHtmlObject "Invalid arguments")
, ("messages", toHtmlObject ia)
]
defaultErrorHandler (InternalError e) =
applyLayout' "Internal Server Error" $ cs $ toHtmlObject
[ ("Internal server error", e)
]
toWaiApp :: Yesod y => y -> IO W.Application
toWaiApp a = do
key <- encryptKey a
let mins = clientSessionDuration a
return $ gzip
$ jsonp
$ methodOverride
$ cleanPath
$ \thePath -> clientsession encryptedCookies key mins
$ toWaiApp' a thePath
toWaiApp' :: Yesod y
=> y
-> [B.ByteString]
-> [(B.ByteString, B.ByteString)]
-> W.Request
-> IO W.Response
toWaiApp' y resource session env = do
let site = getSite getMethod badMethod y
types = httpAccept env
pathSegments = filter (not . null) $ cleanupSegments resource
eurl = parsePathSegments site pathSegments
render u = approot y ++ '/'
: encodePathInfo (formatPathSegments site u)
rr <- parseWaiRequest env session
onRequest y rr
print pathSegments
let ya = case eurl of
Left _ -> runHandler (errorHandler NotFound) y render
Right url -> handleSite site render url
ya errorHandler rr types >>= responseToWaiResponse
getMethod :: (String -> YesodApp y) -> YesodApp y
getMethod f eh req cts =
let m = B8.unpack $ W.methodToBS $ W.requestMethod $ reqWaiRequest req
in f m eh req cts
cleanupSegments :: [B.ByteString] -> [String]
cleanupSegments = decodePathInfo . intercalate "/" . map B8.unpack
httpAccept :: W.Request -> [ContentType]
httpAccept = map contentTypeFromBS
. parseHttpAccept
. fromMaybe B.empty
. lookup W.Accept
. W.requestHeaders
-- | Runs an application with CGI if CGI variables are present (namely
-- PATH_INFO); otherwise uses SimpleServer.
basicHandler :: Int -- ^ port number
-> W.Application -> IO ()
basicHandler port app = do
vars <- getEnvironment
case lookup "PATH_INFO" vars of
Nothing -> do
putStrLn $ "http://localhost:" ++ show port ++ "/"
SS.run port app
Just _ -> CGI.run app
badMethod :: YesodApp y
badMethod _ _ _ = return $ Response W.Status405 [] TypePlain
$ cs "Method not supported"