Reference + Entity = Refty ♡

Formatted JSON generator for API server inspired by normalizr.

We will generate json like:

{ "entities": { "users": { "1": { "id": 1, "name": "Lelouch" }, "2": { "id": 2, "name": "Suzaku" }, "3": { "id": 3, "name": "Jeremiah" } }, "comments": { "1": { "id": 1, "body": "Hello", "userId": 1 }, "4": { "id": 4, "body": "Foo", "userId": 1 }, "2": { "id": 2, "body": "World", "userId": 1 }, "3": { "id": 3, "body": ":)", "userId": 3 } } }, "references": { "self": [ 2, 1, 3 ], "userComments": { "1": [ 1, 4, 2 ], "3": [ 3 ] } } }

First, define data types like:

User.hs:

import Data.Aeson import Data.Text as T import GHC.Generics (Generic) data User = User { id :: Int , name :: T.Text } deriving (Generic, Show) instance ToJSON User 

Comment.hs:

import Data.Aeson import Data.Text as T import GHC.Generics (Generic) data Comment = Comment { id :: Int , userId :: Int , body :: T.Text } deriving (Generic, Show) instance ToJSON Comment 

Next, create JSON.

import Data.Aeson import Refty import qualified User as U import qualified Comment as C -- Sample data users = [ U.User 2 "Suzaku" , U.User 1 "Lelouch" , U.User 3 "Jeremiah" ] comments = [ C.Comment 1 1 "Hello" , C.Comment 4 1 "Foo" , C.Comment 2 1 "World" , C.Comment 3 3 ":)" ] encode $ refty [ builder (resource "users" U.id $ listEntity users) [ selfRef "self" ] , builder (resource "comments" C.id $ listEntity comments) [ hasManyRef "userComments" C.userId ] ]