如何使用Happstack创建JSON Rest API？JSON身体？

Question

我正在尝试使用Happstack创建一个JSON REST api。它应该允许带有JSON主体的帖子。我该怎么做呢？happstack的API中的所有函数似乎都是根据参数名进行查找的。它认为正文始终是url编码的。

如果不能使用Happstack，我应该使用哪个框架？

Answer 1

好吧，这是我想出来的。

{-# LANGUAGE OverloadedStrings, DeriveDataTypeable #-}
import qualified Data.ByteString.Lazy.Char8 as L
import Happstack.Server
import Happstack.Server.Types
import Control.Monad.IO.Class (liftIO)

import Data.Data (Data, Typeable)

-- easiest to serialize/deserialize objects
data Unit = Unit { x :: Int, y :: Int } deriving (Show, Eq, Data, Typeable)

-- put this function in a library somewhere
getBody :: ServerPart L.ByteString
getBody = do
    req  <- askRq 
    body <- liftIO $ takeRequestBody req 
    case body of 
        Just rqbody -> return . unBody $ rqbody 
        Nothing     -> return "" 

myRoute :: ServerPart Response
myRoute = do
    body <- getBody -- it's a ByteString
    let unit = fromJust $ A.decode body :: Unit -- how to parse json
    ok $ toResponse $ A.encode unit -- how to send json back.