highjson
Intro
Hackage: highjson
Low boilerplate, easy to use and very fast Haskell JSON serialisation and
parsing without the help of TemplateHaskell or Generics built on top of aeson. The optional package highjson-swagger will also help automatically generating a OpenAPI schema.
Usage
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PartialTypeSignatures #-}
import Data.Aeson
import Data.HighJson
import Data.HighJson.Swagger -- optional
import Data.Swagger -- optional
data SomeDummy
= SomeDummy
{ sd_int :: Int
, sd_bool :: Bool
, sd_text :: T.Text
, sd_either :: Either Bool T.Text
, sd_maybe :: Maybe Int
} deriving (Show, Eq)
someDummySpec :: RecordTypeSpec SomeDummy _
someDummySpec =
recSpec "Some Dummy" Nothing SomeDummy $
"int" .= sd_int
:& "bool" .= sd_bool
:& "text" .= sd_text
:& "either" .= sd_either
:& "maybe" .= sd_maybe
instance ToJSON SomeDummy where
toJSON = jsonSerializer someDummySpec
toEncoding = jsonEncoder someDummySpec
instance FromJSON SomeDummy where
parseJSON = jsonParser someDummySpec
instance ToSchema SomeSum where -- optional, generates swagger2 specifications
declareNamedSchema p = makeDeclareNamedSchema someDummySpec p
test =
decodeEither "{\"int\": 34, \"text\": \"Teext\", \"bool\": true}"
== Right (SomeDummy 34 True "Teext" Nothing)Template haskell
There's also a small shortcut via template haskell (highjson-th):
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PartialTypeSignatures #-}
{-# LANGUAGE TemplateHaskell #-}
import Data.HighJson
import Data.HighJson.Swagger
import Data.HighJson.TH
data SomeDummy
= SomeDummy
{ sd_int :: Int
, sd_bool :: Bool
, sd_text :: T.Text
, sd_either :: Either Bool T.Text
, sd_maybe :: Maybe Int
} deriving (Show, Eq)
someDummySpec :: RecordTypeSpec SomeDummy _
someDummySpec =
recSpec "Some Dummy" Nothing SomeDummy $
"int" .= sd_int
:& "bool" .= sd_bool
:& "text" .= sd_text
:& "either" .= sd_either
:& "maybe" .= sd_maybe
$(deriveJsonSwagger ''SomeDummy 'someDummySpec)
test =
decodeEither "{\"int\": 34, \"text\": \"Teext\", \"bool\": true}"
== Right (SomeDummy 34 True "Teext" Nothing)Tests
For more usage examples check the tests.
Install
- Using cabal:
cabal install highjson - From Source:
git clone https://github.com/agrafix/highjson.git && cd highjson && cabal install
Benchmarks
There are benchmarks in the project and it is expected to be en par or faster than aesons generic instances.
