gRPC-haskell/examples/echo/echo-hs/EchoServer.hs

{-# LANGUAGE DataKinds         #-}
{-# LANGUAGE DeriveGeneric     #-}
{-# LANGUAGE GADTs             #-}
{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE OverloadedLists   #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards   #-}
{-# LANGUAGE TypeOperators     #-}

import           Data.ByteString                  (ByteString)
import           Data.Maybe                       (fromMaybe)
import           Network.GRPC.HighLevel.Generated (GRPCMethodType (..),
                                                   Host (..), Port (..),
                                                   ServerRequest (..),
                                                   ServerResponse (..),
                                                   StatusCode (..),
                                                   defaultServiceOptions,
                                                   serverHost, serverPort)
import           Options.Generic

import           Echo

data Args = Args
  { bind :: Maybe ByteString <?> "grpc endpoint hostname (default \"localhost\")"
  , port :: Maybe Int        <?> "grpc endpoint port (default 50051)"
  } deriving (Generic, Show)
instance ParseRecord Args

doEcho :: ServerRequest 'Normal EchoRequest EchoResponse
       -> IO (ServerResponse 'Normal EchoResponse)
doEcho (ServerNormalRequest _meta (EchoRequest pay)) = do
  return (ServerNormalResponse (EchoResponse pay) mempty StatusOk "")

main :: IO ()
main = do
  Args{..} <- getRecord "Runs the echo service"
  let opts = defaultServiceOptions
             { serverHost = Host . fromMaybe "localhost" . unHelpful $ bind
             , serverPort = Port . fromMaybe 50051       . unHelpful $ port
             }
  echoServer Echo{ echoDoEcho = doEcho } opts