servant/servant-http-streams
2021-12-09 10:09:18 +01:00
..
src/Servant Derive HasClient good response status from Verb status (#1469) 2021-12-09 10:09:18 +01:00
test unsupporting GHC < 8.6.5, removing unecessary imports 2021-10-02 13:13:24 +02:00
CHANGELOG.md Prepare 0.18.3 release (#1430) 2021-06-24 00:38:46 +03:00
LICENSE Add servant-http-streams 2019-02-06 12:15:30 +02:00
README.lhs Add servant-http-streams 2019-02-06 12:15:30 +02:00
README.md Add servant-http-streams 2019-02-06 12:15:30 +02:00
servant-http-streams.cabal Change the license value to a valid SPDX identifier 2021-10-31 22:37:56 +01:00
Setup.hs Add servant-http-streams 2019-02-06 12:15:30 +02:00

servant-client

servant

This library lets you automatically derive Haskell functions that let you query each endpoint of a servant webservice.

Example

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}

import Data.Proxy
import Data.Text
import Servant.API
import Servant.HttpStreams


type Book = Text

type MyApi = "books" :> Get '[JSON] [Book] -- GET /books
        :<|> "books" :> ReqBody '[JSON] Book :> Post '[JSON] Book -- POST /books

myApi :: Proxy MyApi
myApi = Proxy

-- 'client' allows you to produce operations to query an API from a client.
postNewBook :: Book -> ClientM Book
getAllBooks :: ClientM [Book]
(getAllBooks :<|> postNewBook) = client myApi

-- the IOException happens already in withClientEnvIO
main' :: IO ()
main' = do
    let burl = BaseUrl Http "localhost" 8081 ""
    withClientEnvIO burl $ \env -> do
        res <- runClientM getAllBooks env
        case res of
            Left err -> putStrLn $ "Error: " ++ show err
            Right books -> print books

main :: IO ()
main = return ()