servant-jquery

This library lets you derive automatically (JQuery based) Javascript functions that let you query each endpoint of a servant webservice.

Example

Read more about the following example here.

{-# LANGUAGE DataKinds #-} {-# LANGUAGE TypeOperators #-} {-# LANGUAGE DeriveGeneric #-} {-# LANGUAGE GeneralizedNewtypeDeriving #-} import Control.Concurrent.STM import Control.Monad.IO.Class import Data.Aeson import Data.Proxy import GHC.Generics import Network.Wai.Handler.Warp (run) import Servant import Servant.JQuery import System.FilePath -- * A simple Counter data type newtype Counter = Counter { value :: Int } deriving (Generic, Show, Num) instance ToJSON Counter -- * Shared counter operations -- Creating a counter that starts from 0 newCounter :: IO (TVar Counter) newCounter = newTVarIO 0 -- Increasing the counter by 1 counterPlusOne :: MonadIO m => TVar Counter -> m Counter counterPlusOne counter = liftIO . atomically $ do oldValue <- readTVar counter let newValue = oldValue + 1 writeTVar counter newValue return newValue currentValue :: MonadIO m => TVar Counter -> m Counter currentValue counter = liftIO $ readTVarIO counter -- * Our API type type TestApi = "counter" :> Post Counter -- endpoint for increasing the counter :<|> "counter" :> Get Counter -- endpoint to get the current value :<|> Raw -- used for serving static files testApi :: Proxy TestApi testApi = Proxy -- * Server-side handler -- where our static files reside www :: FilePath www = "examples/www" -- defining handlers server :: TVar Counter -> Server TestApi server counter = counterPlusOne counter -- (+1) on the TVar :<|> currentValue counter -- read the TVar :<|> serveDirectory www -- serve static files runServer :: TVar Counter -- ^ shared variable for the counter -> Int -- ^ port the server should listen on -> IO () runServer var port = run port (serve testApi $ server var) -- * Generating the JQuery code incCounterJS :<|> currentValueJS :<|> _ = jquery testApi writeJS :: FilePath -> [AjaxReq] -> IO () writeJS fp functions = writeFile fp $ concatMap generateJS functions main :: IO () main = do -- write the JS code to www/api.js at startup writeJS (www </> "api.js") [ incCounterJS, currentValueJS ] -- setup a shared counter cnt <- newCounter -- listen to requests on port 8080 runServer cnt 8080