yesod/Yesod/Json.hs
2010-05-02 07:53:08 +03:00

102 lines
2.4 KiB
Haskell

-- FIXME document
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE CPP #-}
module Yesod.Json
( Json
, jsonToContent
-- * Generate Json output
, jsonScalar
, jsonList
, jsonList'
, jsonMap
, jsonMap'
#if TEST
, testSuite
#endif
)
where
import Text.Hamlet.Monad
import Control.Applicative
import Data.Text (Text, pack)
import Web.Encodings
import Yesod.Hamlet
import Yesod.Definitions
import Control.Monad (when)
import Yesod.Handler
import Yesod.Content
#if TEST
import Test.Framework (testGroup, Test)
import Test.Framework.Providers.HUnit
import Test.HUnit hiding (Test)
import Data.Text.Lazy (unpack)
#endif
newtype Json url a = Json { unJson :: Hamlet url IO a }
deriving (Functor, Applicative, Monad)
jsonToContent :: Json (Routes master) () -> GHandler sub master Content
jsonToContent = hamletToContent . unJson
htmlContentToText :: HtmlContent -> Text
htmlContentToText (Encoded t) = t
htmlContentToText (Unencoded t) = encodeHtml t
jsonScalar :: HtmlContent -> Json url ()
jsonScalar s = Json $ do
outputString "\""
output $ encodeJson $ htmlContentToText s
outputString "\""
jsonList :: [Json url ()] -> Json url ()
jsonList = jsonList' . fromList
jsonList' :: Enumerator (Json url ()) (Json url) -> Json url () -- FIXME simplify type
jsonList' (Enumerator enum) = do
Json $ outputString "["
_ <- enum go False
Json $ outputString "]"
where
go putComma j = do
when putComma $ Json $ outputString ","
() <- j
return $ Right True
jsonMap :: [(String, Json url ())] -> Json url ()
jsonMap = jsonMap' . fromList
jsonMap' :: Enumerator (String, Json url ()) (Json url) -> Json url () -- FIXME simplify type
jsonMap' (Enumerator enum) = do
Json $ outputString "{"
_ <- enum go False
Json $ outputString "}"
where
go putComma (k, v) = do
when putComma $ Json $ outputString ","
jsonScalar $ Unencoded $ pack k
Json $ outputString ":"
() <- v
return $ Right True
#if TEST
testSuite :: Test
testSuite = testGroup "Yesod.Json"
[ testCase "simple output" caseSimpleOutput
]
caseSimpleOutput :: Assertion
caseSimpleOutput = do
let j = do
jsonMap
[ ("foo" , jsonList
[ jsonScalar $ Encoded $ pack "bar"
, jsonScalar $ Encoded $ pack "baz"
])
]
t <- hamletToText id $ unJson j
"{\"foo\":[\"bar\",\"baz\"]}" @=? unpack t
#endif