Safe Haskell	None
Language	Haskell98

Yesod.Core.Json

Contents

Convert from a JSON value
Convert to a JSON value
Produce JSON values
Convenience functions

Synopsis

Convert from a JSON value

defaultLayoutJson Source #

Arguments

:: (Yesod site, ToJSON a)
=> WidgetFor site ()	HTML
-> HandlerFor site a	JSON
-> HandlerFor site TypedContent

Provide both an HTML and JSON representation for a piece of data, using the default layout for the HTML output (defaultLayout).

Since: 0.3.0

jsonToRepJson :: (Monad m, ToJSON a) => a -> m Value Source #

Deprecated: Use returnJson instead

Wraps a data type in a RepJson. The data type must support conversion to JSON via ToJSON.

Since: 0.3.0

returnJson :: (Monad m, ToJSON a) => a -> m Value Source #

Convert a value to a JSON representation via aeson's toJSON function.

Since: 1.2.1

returnJsonEncoding :: (Monad m, ToJSON a) => a -> m Encoding Source #

Convert a value to a JSON representation via aeson's toEncoding function.

Since: 1.4.21

provideJson :: (Monad m, ToJSON a) => a -> Writer (Endo [ProvidedRep m]) () Source #

Provide a JSON representation for usage with selectReps, using aeson's toJSON (aeson >= 0.11: toEncoding) function to perform the conversion.

Since: 1.2.1

Convert to a JSON value

parseJsonBody :: (MonadHandler m, FromJSON a) => m (Result a) Source #

Parse the request body to a data type as a JSON value. The data type must support conversion from JSON via FromJSON. If you want the raw JSON value, just ask for a Result Value.

Note that this function will consume the request body. As such, calling it twice will result in a parse error on the second call, since the request body will no longer be available.

Since: 0.3.0

parseCheckJsonBody :: (MonadHandler m, FromJSON a) => m (Result a) Source #

Same as parseJsonBody, but ensures that the mime type indicates JSON content.

parseJsonBody_ :: (MonadHandler m, FromJSON a) => m a Source #

Deprecated: Use requireJsonBody instead

Same as parseJsonBody, but return an invalid args response on a parse error.

requireJsonBody :: (MonadHandler m, FromJSON a) => m a Source #

Same as parseJsonBody, but return an invalid args response on a parse error.

requireCheckJsonBody :: (MonadHandler m, FromJSON a) => m a Source #

Same as requireJsonBody, but ensures that the mime type indicates JSON content.

Produce JSON values

data Value :: * #

Constructors

Object !Object
Array !Array
String !Text
Number !Scientific
Bool !Bool
Null

Instances

Eq Value
Methods (==) :: Value -> Value -> Bool # (/=) :: Value -> Value -> Bool #
Data Value
Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Value -> c Value # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Value # toConstr :: Value -> Constr # dataTypeOf :: Value -> DataType # dataCast1 :: Typeable (* -> ) t => (forall d. Data d => c (t d)) -> Maybe (c Value) # dataCast2 :: Typeable ( -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Value) # gmapT :: (forall b. Data b => b -> b) -> Value -> Value # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Value -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Value -> r # gmapQ :: (forall d. Data d => d -> u) -> Value -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Value -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Value -> m Value # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Value -> m Value # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Value -> m Value #
Read Value
Methods readsPrec :: Int -> ReadS Value # readList :: ReadS [Value] # readPrec :: ReadPrec Value # readListPrec :: ReadPrec [Value] #
Show Value
Methods showsPrec :: Int -> Value -> ShowS # show :: Value -> String # showList :: [Value] -> ShowS #
IsString Value
Methods fromString :: String -> Value #
Generic Value
Associated Types type Rep Value :: * -> * # Methods from :: Value -> Rep Value x # to :: Rep Value x -> Value #
Lift Value
Methods lift :: Value -> Q Exp #
Hashable Value
Methods hashWithSalt :: Int -> Value -> Int hash :: Value -> Int
NFData Value
Methods rnf :: Value -> () #
ToJavascript Value
Methods toJavascript :: Value -> Javascript
ToJSON Value
Methods toJSON :: Value -> Value # toEncoding :: Value -> Encoding # toJSONList :: [Value] -> Value # toEncodingList :: [Value] -> Encoding #
KeyValue Pair
Methods (.=) :: ToJSON v => Text -> v -> Pair #
FromJSON Value
Methods parseJSON :: Value -> Parser Value # parseJSONList :: Value -> Parser [Value] #
ToTypedContent Value Source #
Methods toTypedContent :: Value -> TypedContent Source #
ToTypedContent Encoding Source #
Methods toTypedContent :: Encoding -> TypedContent Source #
HasContentType Value Source #
Methods getContentType :: Monad m => m Value -> ContentType Source #
HasContentType Encoding Source #
Methods getContentType :: Monad m => m Encoding -> ContentType Source #
ToContent Value Source #
Methods toContent :: Value -> Content Source #
ToContent Encoding Source #
Methods toContent :: Encoding -> Content Source #
FromString Value
Methods fromString :: String -> Value
FromString Encoding
Methods fromString :: String -> Encoding
GKeyValue Encoding Series
Methods gPair :: String -> Encoding -> Series
FromPairs Encoding Series
Methods fromPairs :: Series -> Encoding
GToJSON Value arity (U1 *)
Methods gToJSON :: Options -> ToArgs Value arity a -> U1 * a -> Value
GToJSON Encoding arity (U1 *)
Methods gToJSON :: Options -> ToArgs Encoding arity a -> U1 * a -> Encoding
ToJSON1 f => GToJSON Value One (Rec1 * f)
Methods gToJSON :: Options -> ToArgs Value One a -> Rec1 * f a -> Value
ToJSON1 f => GToJSON Encoding One (Rec1 * f)
Methods gToJSON :: Options -> ToArgs Encoding One a -> Rec1 * f a -> Encoding
ToJSON a => GToJSON Value arity (K1 * i a)
Methods gToJSON :: Options -> ToArgs Value arity a -> K1 * i a a -> Value
(WriteProduct arity a, WriteProduct arity b, ProductSize a, ProductSize b) => GToJSON Value arity ((::) a b)
Methods gToJSON :: Options -> ToArgs Value arity a -> (* :*: a) b a -> Value
ToJSON a => GToJSON Encoding arity (K1 * i a)
Methods gToJSON :: Options -> ToArgs Encoding arity a -> K1 * i a a -> Encoding
(EncodeProduct arity a, EncodeProduct arity b) => GToJSON Encoding arity ((::) a b)
Methods gToJSON :: Options -> ToArgs Encoding arity a -> (* :*: a) b a -> Encoding
(ToJSON1 f, GToJSON Value One g) => GToJSON Value One ((:.:) * * f g)
Methods gToJSON :: Options -> ToArgs Value One a -> (* :.: *) f g a -> Value
(ToJSON1 f, GToJSON Encoding One g) => GToJSON Encoding One ((:.:) * * f g)
Methods gToJSON :: Options -> ToArgs Encoding One a -> (* :.: *) f g a -> Encoding
ToJSON v => GKeyValue v (DList Pair)
Methods gPair :: String -> v -> DList Pair
FromPairs Value (DList Pair)
Methods fromPairs :: DList Pair -> Value
(GToJSON Value arity a, ConsToJSON Value arity a, Constructor Meta c) => SumToJSON' * TwoElemArray Value arity (C1 * c a)
Methods sumToJSON' :: Options -> ToArgs arity (C1 * c a) a -> f a -> Tagged TwoElemArray Value arity
(GToJSON Encoding arity a, ConsToJSON Encoding arity a, Constructor Meta c) => SumToJSON' * TwoElemArray Encoding arity (C1 * c a)
Methods sumToJSON' :: Options -> ToArgs arity (C1 * c a) a -> f a -> Tagged TwoElemArray Encoding arity
type Rep Value
type Rep Value = D1 * (MetaData "Value" "Data.Aeson.Types.Internal" "aeson-1.2.4.0-LppEAo2OIFyB0K0s2DngS9" False) ((:+:) * ((:+:) * (C1 * (MetaCons "Object" PrefixI False) (S1 * (MetaSel (Nothing Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 * Object))) ((:+:) * (C1 * (MetaCons "Array" PrefixI False) (S1 * (MetaSel (Nothing Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 * Array))) (C1 * (MetaCons "String" PrefixI False) (S1 * (MetaSel (Nothing Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 * Text))))) ((:+:) * (C1 * (MetaCons "Number" PrefixI False) (S1 * (MetaSel (Nothing Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 * Scientific))) ((:+:) * (C1 * (MetaCons "Bool" PrefixI False) (S1 * (MetaSel (Nothing Symbol) NoSourceUnpackedness SourceStrict DecidedStrict) (Rec0 * Bool))) (C1 * (MetaCons "Null" PrefixI False) (U1 *)))))

class ToJSON a where #

Methods

toJSON :: a -> Value #

toEncoding :: a -> Encoding #

toJSONList :: [a] -> Value #

toEncodingList :: [a] -> Encoding #

Instances

ToJSON Bool
Methods toJSON :: Bool -> Value # toEncoding :: Bool -> Encoding # toJSONList :: [Bool] -> Value # toEncodingList :: [Bool] -> Encoding #
ToJSON Char
Methods toJSON :: Char -> Value # toEncoding :: Char -> Encoding # toJSONList :: [Char] -> Value # toEncodingList :: [Char] -> Encoding #
ToJSON Double
Methods toJSON :: Double -> Value # toEncoding :: Double -> Encoding # toJSONList :: [Double] -> Value # toEncodingList :: [Double] -> Encoding #
ToJSON Float
Methods toJSON :: Float -> Value # toEncoding :: Float -> Encoding # toJSONList :: [Float] -> Value # toEncodingList :: [Float] -> Encoding #
ToJSON Int
Methods toJSON :: Int -> Value # toEncoding :: Int -> Encoding # toJSONList :: [Int] -> Value # toEncodingList :: [Int] -> Encoding #
ToJSON Int8
Methods toJSON :: Int8 -> Value # toEncoding :: Int8 -> Encoding # toJSONList :: [Int8] -> Value # toEncodingList :: [Int8] -> Encoding #
ToJSON Int16
Methods toJSON :: Int16 -> Value # toEncoding :: Int16 -> Encoding # toJSONList :: [Int16] -> Value # toEncodingList :: [Int16] -> Encoding #
ToJSON Int32
Methods toJSON :: Int32 -> Value # toEncoding :: Int32 -> Encoding # toJSONList :: [Int32] -> Value # toEncodingList :: [Int32] -> Encoding #
ToJSON Int64
Methods toJSON :: Int64 -> Value # toEncoding :: Int64 -> Encoding # toJSONList :: [Int64] -> Value # toEncodingList :: [Int64] -> Encoding #
ToJSON Integer
Methods toJSON :: Integer -> Value # toEncoding :: Integer -> Encoding # toJSONList :: [Integer] -> Value # toEncodingList :: [Integer] -> Encoding #
ToJSON Natural
Methods toJSON :: Natural -> Value # toEncoding :: Natural -> Encoding # toJSONList :: [Natural] -> Value # toEncodingList :: [Natural] -> Encoding #
ToJSON Ordering
Methods toJSON :: Ordering -> Value # toEncoding :: Ordering -> Encoding # toJSONList :: [Ordering] -> Value # toEncodingList :: [Ordering] -> Encoding #
ToJSON Word
Methods toJSON :: Word -> Value # toEncoding :: Word -> Encoding # toJSONList :: [Word] -> Value # toEncodingList :: [Word] -> Encoding #
ToJSON Word8
Methods toJSON :: Word8 -> Value # toEncoding :: Word8 -> Encoding # toJSONList :: [Word8] -> Value # toEncodingList :: [Word8] -> Encoding #
ToJSON Word16
Methods toJSON :: Word16 -> Value # toEncoding :: Word16 -> Encoding # toJSONList :: [Word16] -> Value # toEncodingList :: [Word16] -> Encoding #
ToJSON Word32
Methods toJSON :: Word32 -> Value # toEncoding :: Word32 -> Encoding # toJSONList :: [Word32] -> Value # toEncodingList :: [Word32] -> Encoding #
ToJSON Word64
Methods toJSON :: Word64 -> Value # toEncoding :: Word64 -> Encoding # toJSONList :: [Word64] -> Value # toEncodingList :: [Word64] -> Encoding #
ToJSON ()
Methods toJSON :: () -> Value # toEncoding :: () -> Encoding # toJSONList :: [()] -> Value # toEncodingList :: [()] -> Encoding #
ToJSON Text
Methods toJSON :: Text -> Value # toEncoding :: Text -> Encoding # toJSONList :: [Text] -> Value # toEncodingList :: [Text] -> Encoding #
ToJSON UTCTime
Methods toJSON :: UTCTime -> Value # toEncoding :: UTCTime -> Encoding # toJSONList :: [UTCTime] -> Value # toEncodingList :: [UTCTime] -> Encoding #
ToJSON Version
Methods toJSON :: Version -> Value # toEncoding :: Version -> Encoding # toJSONList :: [Version] -> Value # toEncodingList :: [Version] -> Encoding #
ToJSON CTime
Methods toJSON :: CTime -> Value # toEncoding :: CTime -> Encoding # toJSONList :: [CTime] -> Value # toEncodingList :: [CTime] -> Encoding #
ToJSON Text
Methods toJSON :: Text -> Value # toEncoding :: Text -> Encoding # toJSONList :: [Text] -> Value # toEncodingList :: [Text] -> Encoding #
ToJSON IntSet
Methods toJSON :: IntSet -> Value # toEncoding :: IntSet -> Encoding # toJSONList :: [IntSet] -> Value # toEncodingList :: [IntSet] -> Encoding #
ToJSON DiffTime
Methods toJSON :: DiffTime -> Value # toEncoding :: DiffTime -> Encoding # toJSONList :: [DiffTime] -> Value # toEncodingList :: [DiffTime] -> Encoding #
ToJSON ZonedTime
Methods toJSON :: ZonedTime -> Value # toEncoding :: ZonedTime -> Encoding # toJSONList :: [ZonedTime] -> Value # toEncodingList :: [ZonedTime] -> Encoding #
ToJSON LocalTime
Methods toJSON :: LocalTime -> Value # toEncoding :: LocalTime -> Encoding # toJSONList :: [LocalTime] -> Value # toEncodingList :: [LocalTime] -> Encoding #
ToJSON TimeOfDay
Methods toJSON :: TimeOfDay -> Value # toEncoding :: TimeOfDay -> Encoding # toJSONList :: [TimeOfDay] -> Value # toEncodingList :: [TimeOfDay] -> Encoding #
ToJSON NominalDiffTime
Methods toJSON :: NominalDiffTime -> Value # toEncoding :: NominalDiffTime -> Encoding # toJSONList :: [NominalDiffTime] -> Value # toEncodingList :: [NominalDiffTime] -> Encoding #
ToJSON Day
Methods toJSON :: Day -> Value # toEncoding :: Day -> Encoding # toJSONList :: [Day] -> Value # toEncodingList :: [Day] -> Encoding #
ToJSON Value
Methods toJSON :: Value -> Value # toEncoding :: Value -> Encoding # toJSONList :: [Value] -> Value # toEncodingList :: [Value] -> Encoding #
ToJSON Scientific
Methods toJSON :: Scientific -> Value # toEncoding :: Scientific -> Encoding # toJSONList :: [Scientific] -> Value # toEncodingList :: [Scientific] -> Encoding #
ToJSON Number
Methods toJSON :: Number -> Value # toEncoding :: Number -> Encoding # toJSONList :: [Number] -> Value # toEncodingList :: [Number] -> Encoding #
ToJSON UUID
Methods toJSON :: UUID -> Value # toEncoding :: UUID -> Encoding # toJSONList :: [UUID] -> Value # toEncodingList :: [UUID] -> Encoding #
ToJSON DotNetTime
Methods toJSON :: DotNetTime -> Value # toEncoding :: DotNetTime -> Encoding # toJSONList :: [DotNetTime] -> Value # toEncodingList :: [DotNetTime] -> Encoding #
ToJSON a => ToJSON [a]
Methods toJSON :: [a] -> Value # toEncoding :: [a] -> Encoding # toJSONList :: [[a]] -> Value # toEncodingList :: [[a]] -> Encoding #
ToJSON a => ToJSON (Maybe a)
Methods toJSON :: Maybe a -> Value # toEncoding :: Maybe a -> Encoding # toJSONList :: [Maybe a] -> Value # toEncodingList :: [Maybe a] -> Encoding #
(ToJSON a, Integral a) => ToJSON (Ratio a)
Methods toJSON :: Ratio a -> Value # toEncoding :: Ratio a -> Encoding # toJSONList :: [Ratio a] -> Value # toEncodingList :: [Ratio a] -> Encoding #
HasResolution a => ToJSON (Fixed a)
Methods toJSON :: Fixed a -> Value # toEncoding :: Fixed a -> Encoding # toJSONList :: [Fixed a] -> Value # toEncodingList :: [Fixed a] -> Encoding #
ToJSON a => ToJSON (Min a)
Methods toJSON :: Min a -> Value # toEncoding :: Min a -> Encoding # toJSONList :: [Min a] -> Value # toEncodingList :: [Min a] -> Encoding #
ToJSON a => ToJSON (Max a)
Methods toJSON :: Max a -> Value # toEncoding :: Max a -> Encoding # toJSONList :: [Max a] -> Value # toEncodingList :: [Max a] -> Encoding #
ToJSON a => ToJSON (First a)
Methods toJSON :: First a -> Value # toEncoding :: First a -> Encoding # toJSONList :: [First a] -> Value # toEncodingList :: [First a] -> Encoding #
ToJSON a => ToJSON (Last a)
Methods toJSON :: Last a -> Value # toEncoding :: Last a -> Encoding # toJSONList :: [Last a] -> Value # toEncodingList :: [Last a] -> Encoding #
ToJSON a => ToJSON (WrappedMonoid a)
Methods toJSON :: WrappedMonoid a -> Value # toEncoding :: WrappedMonoid a -> Encoding # toJSONList :: [WrappedMonoid a] -> Value # toEncodingList :: [WrappedMonoid a] -> Encoding #
ToJSON a => ToJSON (Option a)
Methods toJSON :: Option a -> Value # toEncoding :: Option a -> Encoding # toJSONList :: [Option a] -> Value # toEncodingList :: [Option a] -> Encoding #
ToJSON a => ToJSON (NonEmpty a)
Methods toJSON :: NonEmpty a -> Value # toEncoding :: NonEmpty a -> Encoding # toJSONList :: [NonEmpty a] -> Value # toEncodingList :: [NonEmpty a] -> Encoding #
ToJSON a => ToJSON (Identity a)
Methods toJSON :: Identity a -> Value # toEncoding :: Identity a -> Encoding # toJSONList :: [Identity a] -> Value # toEncodingList :: [Identity a] -> Encoding #
ToJSON a => ToJSON (Dual a)
Methods toJSON :: Dual a -> Value # toEncoding :: Dual a -> Encoding # toJSONList :: [Dual a] -> Value # toEncodingList :: [Dual a] -> Encoding #
ToJSON a => ToJSON (First a)
Methods toJSON :: First a -> Value # toEncoding :: First a -> Encoding # toJSONList :: [First a] -> Value # toEncodingList :: [First a] -> Encoding #
ToJSON a => ToJSON (Last a)
Methods toJSON :: Last a -> Value # toEncoding :: Last a -> Encoding # toJSONList :: [Last a] -> Value # toEncodingList :: [Last a] -> Encoding #
ToJSON a => ToJSON (IntMap a)
Methods toJSON :: IntMap a -> Value # toEncoding :: IntMap a -> Encoding # toJSONList :: [IntMap a] -> Value # toEncodingList :: [IntMap a] -> Encoding #
ToJSON v => ToJSON (Tree v)
Methods toJSON :: Tree v -> Value # toEncoding :: Tree v -> Encoding # toJSONList :: [Tree v] -> Value # toEncodingList :: [Tree v] -> Encoding #
ToJSON a => ToJSON (Seq a)
Methods toJSON :: Seq a -> Value # toEncoding :: Seq a -> Encoding # toJSONList :: [Seq a] -> Value # toEncodingList :: [Seq a] -> Encoding #
ToJSON a => ToJSON (Set a)
Methods toJSON :: Set a -> Value # toEncoding :: Set a -> Encoding # toJSONList :: [Set a] -> Value # toEncodingList :: [Set a] -> Encoding #
ToJSON a => ToJSON (HashSet a)
Methods toJSON :: HashSet a -> Value # toEncoding :: HashSet a -> Encoding # toJSONList :: [HashSet a] -> Value # toEncodingList :: [HashSet a] -> Encoding #
(Vector Vector a, ToJSON a) => ToJSON (Vector a)
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
ToJSON a => ToJSON (Vector a)
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
(Prim a, ToJSON a) => ToJSON (Vector a)
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
(Storable a, ToJSON a) => ToJSON (Vector a)
Methods toJSON :: Vector a -> Value # toEncoding :: Vector a -> Encoding # toJSONList :: [Vector a] -> Value # toEncodingList :: [Vector a] -> Encoding #
ToJSON a => ToJSON (DList a)
Methods toJSON :: DList a -> Value # toEncoding :: DList a -> Encoding # toJSONList :: [DList a] -> Value # toEncodingList :: [DList a] -> Encoding #
(ToJSON a, ToJSON b) => ToJSON (Either a b)
Methods toJSON :: Either a b -> Value # toEncoding :: Either a b -> Encoding # toJSONList :: [Either a b] -> Value # toEncodingList :: [Either a b] -> Encoding #
(ToJSON a, ToJSON b) => ToJSON (a, b)
Methods toJSON :: (a, b) -> Value # toEncoding :: (a, b) -> Encoding # toJSONList :: [(a, b)] -> Value # toEncodingList :: [(a, b)] -> Encoding #
(ToJSON v, ToJSONKey k) => ToJSON (HashMap k v)
Methods toJSON :: HashMap k v -> Value # toEncoding :: HashMap k v -> Encoding # toJSONList :: [HashMap k v] -> Value # toEncodingList :: [HashMap k v] -> Encoding #
(ToJSON v, ToJSONKey k) => ToJSON (Map k v)
Methods toJSON :: Map k v -> Value # toEncoding :: Map k v -> Encoding # toJSONList :: [Map k v] -> Value # toEncodingList :: [Map k v] -> Encoding #
ToJSON (Proxy k a)
Methods toJSON :: Proxy k a -> Value # toEncoding :: Proxy k a -> Encoding # toJSONList :: [Proxy k a] -> Value # toEncodingList :: [Proxy k a] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c) => ToJSON (a, b, c)
Methods toJSON :: (a, b, c) -> Value # toEncoding :: (a, b, c) -> Encoding # toJSONList :: [(a, b, c)] -> Value # toEncodingList :: [(a, b, c)] -> Encoding #
ToJSON a => ToJSON (Const k a b)
Methods toJSON :: Const k a b -> Value # toEncoding :: Const k a b -> Encoding # toJSONList :: [Const k a b] -> Value # toEncodingList :: [Const k a b] -> Encoding #
ToJSON b => ToJSON (Tagged k a b)
Methods toJSON :: Tagged k a b -> Value # toEncoding :: Tagged k a b -> Encoding # toJSONList :: [Tagged k a b] -> Value # toEncodingList :: [Tagged k a b] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d) => ToJSON (a, b, c, d)
Methods toJSON :: (a, b, c, d) -> Value # toEncoding :: (a, b, c, d) -> Encoding # toJSONList :: [(a, b, c, d)] -> Value # toEncodingList :: [(a, b, c, d)] -> Encoding #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Product * f g a)
Methods toJSON :: Product * f g a -> Value # toEncoding :: Product * f g a -> Encoding # toJSONList :: [Product * f g a] -> Value # toEncodingList :: [Product * f g a] -> Encoding #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Sum * f g a)
Methods toJSON :: Sum * f g a -> Value # toEncoding :: Sum * f g a -> Encoding # toJSONList :: [Sum * f g a] -> Value # toEncodingList :: [Sum * f g a] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e) => ToJSON (a, b, c, d, e)
Methods toJSON :: (a, b, c, d, e) -> Value # toEncoding :: (a, b, c, d, e) -> Encoding # toJSONList :: [(a, b, c, d, e)] -> Value # toEncodingList :: [(a, b, c, d, e)] -> Encoding #
(ToJSON1 f, ToJSON1 g, ToJSON a) => ToJSON (Compose * * f g a)
Methods toJSON :: Compose * * f g a -> Value # toEncoding :: Compose * * f g a -> Encoding # toJSONList :: [Compose * * f g a] -> Value # toEncodingList :: [Compose * * f g a] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f) => ToJSON (a, b, c, d, e, f)
Methods toJSON :: (a, b, c, d, e, f) -> Value # toEncoding :: (a, b, c, d, e, f) -> Encoding # toJSONList :: [(a, b, c, d, e, f)] -> Value # toEncodingList :: [(a, b, c, d, e, f)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g) => ToJSON (a, b, c, d, e, f, g)
Methods toJSON :: (a, b, c, d, e, f, g) -> Value # toEncoding :: (a, b, c, d, e, f, g) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h) => ToJSON (a, b, c, d, e, f, g, h)
Methods toJSON :: (a, b, c, d, e, f, g, h) -> Value # toEncoding :: (a, b, c, d, e, f, g, h) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i) => ToJSON (a, b, c, d, e, f, g, h, i)
Methods toJSON :: (a, b, c, d, e, f, g, h, i) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j) => ToJSON (a, b, c, d, e, f, g, h, i, j)
Methods toJSON :: (a, b, c, d, e, f, g, h, i, j) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k) => ToJSON (a, b, c, d, e, f, g, h, i, j, k)
Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l)
Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m)
Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l, m) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m, ToJSON n) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n)
Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] -> Encoding #
(ToJSON a, ToJSON b, ToJSON c, ToJSON d, ToJSON e, ToJSON f, ToJSON g, ToJSON h, ToJSON i, ToJSON j, ToJSON k, ToJSON l, ToJSON m, ToJSON n, ToJSON o) => ToJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
Methods toJSON :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Value # toEncoding :: (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) -> Encoding # toJSONList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] -> Value # toEncodingList :: [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] -> Encoding #

class FromJSON a where #

Methods

parseJSON :: Value -> Parser a #

parseJSONList :: Value -> Parser [a] #

Instances

FromJSON Bool
Methods parseJSON :: Value -> Parser Bool # parseJSONList :: Value -> Parser [Bool] #
FromJSON Char
Methods parseJSON :: Value -> Parser Char # parseJSONList :: Value -> Parser [Char] #
FromJSON Double
Methods parseJSON :: Value -> Parser Double # parseJSONList :: Value -> Parser [Double] #
FromJSON Float
Methods parseJSON :: Value -> Parser Float # parseJSONList :: Value -> Parser [Float] #
FromJSON Int
Methods parseJSON :: Value -> Parser Int # parseJSONList :: Value -> Parser [Int] #
FromJSON Int8
Methods parseJSON :: Value -> Parser Int8 # parseJSONList :: Value -> Parser [Int8] #
FromJSON Int16
Methods parseJSON :: Value -> Parser Int16 # parseJSONList :: Value -> Parser [Int16] #
FromJSON Int32
Methods parseJSON :: Value -> Parser Int32 # parseJSONList :: Value -> Parser [Int32] #
FromJSON Int64
Methods parseJSON :: Value -> Parser Int64 # parseJSONList :: Value -> Parser [Int64] #
FromJSON Integer
Methods parseJSON :: Value -> Parser Integer # parseJSONList :: Value -> Parser [Integer] #
FromJSON Natural
Methods parseJSON :: Value -> Parser Natural # parseJSONList :: Value -> Parser [Natural] #
FromJSON Ordering
Methods parseJSON :: Value -> Parser Ordering # parseJSONList :: Value -> Parser [Ordering] #
FromJSON Word
Methods parseJSON :: Value -> Parser Word # parseJSONList :: Value -> Parser [Word] #
FromJSON Word8
Methods parseJSON :: Value -> Parser Word8 # parseJSONList :: Value -> Parser [Word8] #
FromJSON Word16
Methods parseJSON :: Value -> Parser Word16 # parseJSONList :: Value -> Parser [Word16] #
FromJSON Word32
Methods parseJSON :: Value -> Parser Word32 # parseJSONList :: Value -> Parser [Word32] #
FromJSON Word64
Methods parseJSON :: Value -> Parser Word64 # parseJSONList :: Value -> Parser [Word64] #
FromJSON ()
Methods parseJSON :: Value -> Parser () # parseJSONList :: Value -> Parser [()] #
FromJSON Text
Methods parseJSON :: Value -> Parser Text # parseJSONList :: Value -> Parser [Text] #
FromJSON UTCTime
Methods parseJSON :: Value -> Parser UTCTime # parseJSONList :: Value -> Parser [UTCTime] #
FromJSON Version
Methods parseJSON :: Value -> Parser Version # parseJSONList :: Value -> Parser [Version] #
FromJSON CTime
Methods parseJSON :: Value -> Parser CTime # parseJSONList :: Value -> Parser [CTime] #
FromJSON Text
Methods parseJSON :: Value -> Parser Text # parseJSONList :: Value -> Parser [Text] #
FromJSON IntSet
Methods parseJSON :: Value -> Parser IntSet # parseJSONList :: Value -> Parser [IntSet] #
FromJSON DiffTime
Methods parseJSON :: Value -> Parser DiffTime # parseJSONList :: Value -> Parser [DiffTime] #
FromJSON ZonedTime
Methods parseJSON :: Value -> Parser ZonedTime # parseJSONList :: Value -> Parser [ZonedTime] #
FromJSON LocalTime
Methods parseJSON :: Value -> Parser LocalTime # parseJSONList :: Value -> Parser [LocalTime] #
FromJSON TimeOfDay
Methods parseJSON :: Value -> Parser TimeOfDay # parseJSONList :: Value -> Parser [TimeOfDay] #
FromJSON NominalDiffTime
Methods parseJSON :: Value -> Parser NominalDiffTime # parseJSONList :: Value -> Parser [NominalDiffTime] #
FromJSON Day
Methods parseJSON :: Value -> Parser Day # parseJSONList :: Value -> Parser [Day] #
FromJSON Value
Methods parseJSON :: Value -> Parser Value # parseJSONList :: Value -> Parser [Value] #
FromJSON Scientific
Methods parseJSON :: Value -> Parser Scientific # parseJSONList :: Value -> Parser [Scientific] #
FromJSON Number
Methods parseJSON :: Value -> Parser Number # parseJSONList :: Value -> Parser [Number] #
FromJSON UUID
Methods parseJSON :: Value -> Parser UUID # parseJSONList :: Value -> Parser [UUID] #
FromJSON DotNetTime
Methods parseJSON :: Value -> Parser DotNetTime # parseJSONList :: Value -> Parser [DotNetTime] #
FromJSON a => FromJSON [a]
Methods parseJSON :: Value -> Parser [a] # parseJSONList :: Value -> Parser [[a]] #
FromJSON a => FromJSON (Maybe a)
Methods parseJSON :: Value -> Parser (Maybe a) # parseJSONList :: Value -> Parser [Maybe a] #
(FromJSON a, Integral a) => FromJSON (Ratio a)
Methods parseJSON :: Value -> Parser (Ratio a) # parseJSONList :: Value -> Parser [Ratio a] #
HasResolution a => FromJSON (Fixed a)
Methods parseJSON :: Value -> Parser (Fixed a) # parseJSONList :: Value -> Parser [Fixed a] #
FromJSON a => FromJSON (Min a)
Methods parseJSON :: Value -> Parser (Min a) # parseJSONList :: Value -> Parser [Min a] #
FromJSON a => FromJSON (Max a)
Methods parseJSON :: Value -> Parser (Max a) # parseJSONList :: Value -> Parser [Max a] #
FromJSON a => FromJSON (First a)
Methods parseJSON :: Value -> Parser (First a) # parseJSONList :: Value -> Parser [First a] #
FromJSON a => FromJSON (Last a)
Methods parseJSON :: Value -> Parser (Last a) # parseJSONList :: Value -> Parser [Last a] #
FromJSON a => FromJSON (WrappedMonoid a)
Methods parseJSON :: Value -> Parser (WrappedMonoid a) # parseJSONList :: Value -> Parser [WrappedMonoid a] #
FromJSON a => FromJSON (Option a)
Methods parseJSON :: Value -> Parser (Option a) # parseJSONList :: Value -> Parser [Option a] #
FromJSON a => FromJSON (NonEmpty a)
Methods parseJSON :: Value -> Parser (NonEmpty a) # parseJSONList :: Value -> Parser [NonEmpty a] #
FromJSON a => FromJSON (Identity a)
Methods parseJSON :: Value -> Parser (Identity a) # parseJSONList :: Value -> Parser [Identity a] #
FromJSON a => FromJSON (Dual a)
Methods parseJSON :: Value -> Parser (Dual a) # parseJSONList :: Value -> Parser [Dual a] #
FromJSON a => FromJSON (First a)
Methods parseJSON :: Value -> Parser (First a) # parseJSONList :: Value -> Parser [First a] #
FromJSON a => FromJSON (Last a)
Methods parseJSON :: Value -> Parser (Last a) # parseJSONList :: Value -> Parser [Last a] #
FromJSON a => FromJSON (IntMap a)
Methods parseJSON :: Value -> Parser (IntMap a) # parseJSONList :: Value -> Parser [IntMap a] #
FromJSON v => FromJSON (Tree v)
Methods parseJSON :: Value -> Parser (Tree v) # parseJSONList :: Value -> Parser [Tree v] #
FromJSON a => FromJSON (Seq a)
Methods parseJSON :: Value -> Parser (Seq a) # parseJSONList :: Value -> Parser [Seq a] #
(Ord a, FromJSON a) => FromJSON (Set a)
Methods parseJSON :: Value -> Parser (Set a) # parseJSONList :: Value -> Parser [Set a] #
(Eq a, Hashable a, FromJSON a) => FromJSON (HashSet a)
Methods parseJSON :: Value -> Parser (HashSet a) # parseJSONList :: Value -> Parser [HashSet a] #
(Vector Vector a, FromJSON a) => FromJSON (Vector a)
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
FromJSON a => FromJSON (Vector a)
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
(Prim a, FromJSON a) => FromJSON (Vector a)
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
(Storable a, FromJSON a) => FromJSON (Vector a)
Methods parseJSON :: Value -> Parser (Vector a) # parseJSONList :: Value -> Parser [Vector a] #
FromJSON a => FromJSON (DList a)
Methods parseJSON :: Value -> Parser (DList a) # parseJSONList :: Value -> Parser [DList a] #
(FromJSON a, FromJSON b) => FromJSON (Either a b)
Methods parseJSON :: Value -> Parser (Either a b) # parseJSONList :: Value -> Parser [Either a b] #
(FromJSON a, FromJSON b) => FromJSON (a, b)
Methods parseJSON :: Value -> Parser (a, b) # parseJSONList :: Value -> Parser [(a, b)] #
(FromJSON v, FromJSONKey k, Eq k, Hashable k) => FromJSON (HashMap k v)
Methods parseJSON :: Value -> Parser (HashMap k v) # parseJSONList :: Value -> Parser [HashMap k v] #
(FromJSONKey k, Ord k, FromJSON v) => FromJSON (Map k v)
Methods parseJSON :: Value -> Parser (Map k v) # parseJSONList :: Value -> Parser [Map k v] #
FromJSON (Proxy k a)
Methods parseJSON :: Value -> Parser (Proxy k a) # parseJSONList :: Value -> Parser [Proxy k a] #
(FromJSON a, FromJSON b, FromJSON c) => FromJSON (a, b, c)
Methods parseJSON :: Value -> Parser (a, b, c) # parseJSONList :: Value -> Parser [(a, b, c)] #
FromJSON a => FromJSON (Const k a b)
Methods parseJSON :: Value -> Parser (Const k a b) # parseJSONList :: Value -> Parser [Const k a b] #
FromJSON b => FromJSON (Tagged k a b)
Methods parseJSON :: Value -> Parser (Tagged k a b) # parseJSONList :: Value -> Parser [Tagged k a b] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d) => FromJSON (a, b, c, d)
Methods parseJSON :: Value -> Parser (a, b, c, d) # parseJSONList :: Value -> Parser [(a, b, c, d)] #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Product * f g a)
Methods parseJSON :: Value -> Parser (Product * f g a) # parseJSONList :: Value -> Parser [Product * f g a] #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Sum * f g a)
Methods parseJSON :: Value -> Parser (Sum * f g a) # parseJSONList :: Value -> Parser [Sum * f g a] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e) => FromJSON (a, b, c, d, e)
Methods parseJSON :: Value -> Parser (a, b, c, d, e) # parseJSONList :: Value -> Parser [(a, b, c, d, e)] #
(FromJSON1 f, FromJSON1 g, FromJSON a) => FromJSON (Compose * * f g a)
Methods parseJSON :: Value -> Parser (Compose * * f g a) # parseJSONList :: Value -> Parser [Compose * * f g a] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f) => FromJSON (a, b, c, d, e, f)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g) => FromJSON (a, b, c, d, e, f, g)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h) => FromJSON (a, b, c, d, e, f, g, h)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i) => FromJSON (a, b, c, d, e, f, g, h, i)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j) => FromJSON (a, b, c, d, e, f, g, h, i, j)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k) => FromJSON (a, b, c, d, e, f, g, h, i, j, k)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m, FromJSON n) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, n) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m, n)] #
(FromJSON a, FromJSON b, FromJSON c, FromJSON d, FromJSON e, FromJSON f, FromJSON g, FromJSON h, FromJSON i, FromJSON j, FromJSON k, FromJSON l, FromJSON m, FromJSON n, FromJSON o) => FromJSON (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)
Methods parseJSON :: Value -> Parser (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o) # parseJSONList :: Value -> Parser [(a, b, c, d, e, f, g, h, i, j, k, l, m, n, o)] #

array :: ToJSON a => [a] -> Value Source #

Convert a list of values to an Array.

object :: [Pair] -> Value #

(.=) :: KeyValue kv => forall v. ToJSON v => Text -> v -> kv #

(.:) :: FromJSON a => Object -> Text -> Parser a #

Convenience functions

jsonOrRedirect Source #

Arguments

:: (MonadHandler m, ToJSON a)
=> Route (HandlerSite m)	Redirect target
-> a	Data to send via JSON
-> m Value

jsonOrRedirect simplifies the scenario where a POST handler sends a different response based on Accept headers:

200 with JSON data if the client prefers application/json (e.g. AJAX, see acceptsJSON).
3xx otherwise, following the PRG pattern.

jsonEncodingOrRedirect Source #

Arguments

:: (MonadHandler m, ToJSON a)
=> Route (HandlerSite m)	Redirect target
-> a	Data to send via JSON
-> m Encoding

jsonEncodingOrRedirect simplifies the scenario where a POST handler sends a different response based on Accept headers:

200 with JSON data if the client prefers application/json (e.g. AJAX, see acceptsJSON).
3xx otherwise, following the PRG pattern. @since 1.4.21

acceptsJson :: MonadHandler m => m Bool Source #

Returns True if the client prefers application/json as indicated by the Accept HTTP header.